I'm using iReport to generate QRcode on my PDF and it generate nicely when I preview on my designer however when I try to use it on my web app I'm getting error as below:  java.lang.NoSuchMethodError: net.sf.jasperreports.engine.util.JRImageLoader.getInstance(Lnet/sf/jasperreports/engine/JasperReportsContext;)Lnet/sf/jasperreports/engine/util/JRImageLoader; at net.sf.jasperreports.engine.RenderableUtil.getRenderable(RenderableUtil.java:172) at net.sf.jasperreports.engine.RenderableUtil.getRenderable(RenderableUtil.java:154) at net.sf.jasperreports.engine.fill.JRFillImage.evaluateImage(JRFillImage.java:516) at net.sf.jasperreports.engine.fill.JRFillImage.evaluate(JRFillImage.java:472) at net.sf.jasperreports.engine.fill.JRFillElementContainer.evaluate(JRFillElementContainer.java:259) at net.sf.jasperreports.engine.fill.JRFillBand.evaluate(JRFillBand.java:456) at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillBandNoOverflow(JRVerticalFiller.java:457) at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillPageHeader(JRVerticalFiller.java:421) at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReportStart(JRVerticalFiller.java:282) at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReport(JRVerticalFiller.java:151) at net.sf.jasperreports.engine.fill.JRBaseFiller.fill(JRBaseFiller.java:939) at net.sf.jasperreports.engine.fill.JRBaseFiller.fill(JRBaseFiller.java:871) at net.sf.jasperreports.engine.fill.JRFiller.fill(JRFiller.java:114) at net.sf.jasperreports.engine.JasperFillManager.fill(JasperFillManager.java:653) at net.sf.jasperreports.engine.JasperFillManager.fill(JasperFillManager.java:569) at net.sf.jasperreports.engine.JasperFillManager.fillReport(JasperFillManager.java:915) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498)  Also I could generate other report on my web app that didn't have QRcode but one report with QRcode will trigger above error. Did I miss some library? Thanks in advance.


Is it thread-safe to read an instance variable while calling a setter from another thread?

I have an object with a property:  @interface Car @property(strong) NSLicensePlate *licensePlate; @end   I use the property in a method:  - (void) doSomething {     [_licensePlate frobnicate]; }   And the property value can be changed in another method:  - (void) doSomethingElse {     [self setLicensePlate:[_licensePlateDealer cleanLicensePlate]]; }   Now, if the -doSomethingElse method is called from another thread while I access the license plate property using the instance variable (as seen in the -doSomething method), is it possible to get a segfault?  Is it possible that the -setLicensePlate setter releases the value stored in _licensePlate right before I call -frobnicate on it and before a new valid value is assigned? And would it help to call [self licensePlate] instead of using _licensePlate directly?


How can I check if a program exists from a Bash script?

How would I validate that a program exists, in a way that will either return an error and exit, or continue with the script?  It seems like it should be easy, but it's been stumping me.


Suggested-Edits-Tool displays more approved users than in edit overview

The  displays more users that approve an edit, than are listed in the overview of an edit.  For example the edit  list the 4 users      Approved 6 mins ago:         martineau reviewed this 5 mins ago: Approve   WATTO Studios reviewed this 5 mins ago: Approve   pXL reviewed this 9 mins ago: Reject   This edit is incorrect or an attempt to reply to or comment on the existing post.   Royston Pinto reviewed this 11 mins ago: Approve      but in the Tools the following users are listed     approved by Volatility, toro2k, danodonovan, Kaz Dragon, Royston   Pinto, WATTO Studios, martineau, pXL 7 mins ago   Also has user pXL rejected the edit and not approved.  I think the Tools list all users that reviewed the edit, but the edit overview lists only first users that reviewed the edit to complete the review state.   If its the case the Tools should say reviewed by.


Using Courier font for mathematical equations (by ignoring math mode)

Recently, I learned about the command \texttt{...} from Werner's (very nice) answer .  Here is a basic example Werner gives:   \documentclass{article} \usepackage{courier} \begin{document} This is not Courier font. \texttt{This is Courier font.} \end{document}    which produces     How can I use the same idea to describe a math equation? For example, I want to see exactly a^2+b^2 = c^2 in Courier font. Trying \texttt{a^2+b^2=c^2} doesn't work because texttt  doesn't seem to interact well with the math mode. But I precisely don't want to use double dollar signs because it displays the expression a^2+b^2=c^2 in math mode, but I explicitly want to see the symbols ^.   For those curious, this is supposed to represent a mathematical input to a software, so I precisely want to write a^2+b^2=c^2 (in Courier font).


Why are my PHP sessions dying? And why can't I restore them?

I have an app using PHP and the PayPal API. The basic way it works to get a payment is that you do a web service call to PayPal to get a token and then do a browser redirect to PayPal with that token for the user to pay. After the payment details have been confirmed, PayPal redirects back to the URL you originally set in the service call.  This all works, millions of people use it every day, et cetera.  Strange thing is, when PayPal redirects back, the PHP session is gone. It's a .  First question: why is this happening? Both pages are on the same domain, both use HTTPS. The session works for all requests up until the PayPal redirect back.  The linked forum thread suggests a workaround, to persist the session ID in the PayPal request and then to retrieve it later and restore the session. Great, except it doesn't seem to work.  I can add some log statements:  log(session_id());   before and after the various redirects. When coming back from PayPal, I log some more.  log("session id is " . session_id()); $session_id = get_session_id_from_paypal(); log("setting it back to " . $session_id); session_id($session_id); session_start(); log("session id is now " . session_id());   The result is not at all what I'd expect:     session_id is fc8f459a186a3f4695ff9ac71b563825   setting it back to 82460dcf8c8ddd538466e7cb89712e72   session_id is now 360ba3fd99d233e0735397278d2b2e55     Second question: why is the session id not at all what I set it to? What am I doing wrong? Or, at least, why do none of the session variables come back?


Advantages of Lagrangian Mechanics over Newtonian Mechanics

Here, I'm going to pose a very serious list of doubts I have on Lagrangian Mechanics.   Can we learn Lagrangian Mechanics without studying Newtonian Mechanics? Does Lagrangian help in solving problems easily, which generally seem to be complicated with Newtonian laws? Does Lagrangian make problem solving faster?


How do I get the directory from where I call the script when the script itself is in a different directory?

I am making a few custom commands to use on my debian server and I am putting them in the /usr/bin folder.  One custom command I wish to make involves getting the directory from where I call the script, NOT the directory in which the script resides.  Nearly all of the questions I find on here involve getting the working directory using  a=$PWD   or  a=$(pwd)   This only returns the directory in which the script resides.  Edit: I am aware of  $OLDPWD   The above will only work some of the time.  Is it possible to do what I want?  Current form of my script:  #!/bin/bash if [ -z "$1" ] then     a=$(pwd)     echo "Unlocking current directory."     sudo chmod 777 -R $a else     echo "Unlocking directory at \"$1\""     sudo chmod 777 -R $1 fi


How open Windows Explorer as different user in Windows 10?

In Windows 10, the Windows Explorer shortcut on the taskbar has a different context menu than previous versions of Windows, and is missing the "Run as..." option (while holding the shift key).   How can I open Explorer as a different user?


What are the differences between sentience, consciousness and awareness?

Dictionary definitions  often seem to use the terms sentience, awareness, and consciousness as if they are synonymous with each other. Is this really the case? If not, how do they differ? Some books suggest that sentience and awareness are simply facets of the larger concept of consciousness.


A commutative ring whose all proper ideals are prime is a field.

Let $R$ be a commutative ring with $1$. Suppose that all ideals $I \neq R$ are prime. Prove that $R$ is a field.   Help me some hints.  Thanks a lot.


How to filter the array of objects using Javascript

I am trying to filter an array of objects and i am using filter method to filter the array of objects but i am unable to filter   [    {       "uid":"ITIzoS7gi1XODY1iQKhltCNFCib2",       "emailVerified":false,        "disabled":false,       "metadata":{          "lastSignInTime":"Fri, 01 May 2020 07:03:52 GMT",          "creationTime":"Fri, 01 May 2020 07:01:50 GMT"       },       "customClaims":{          "admin":[             "Sk nagar"          ]       },       "tokensValidAfterTime":"Fri, 01 May 2020 07:06:12 GMT",     },    {       "uid":"JOdx4er51ibvaN4IChSJyhdLkot1",       "emailVerified":false,        "disabled":false,       "metadata":{          "lastSignInTime":"Thu, 30 Apr 2020 05:40:21 GMT",          "creationTime":"Thu, 30 Apr 2020 05:40:21 GMT"       },       "customClaims":{},     },    {       "uid":"PR837CY9aibZMcQ1Ux9ELOBNhus1",       "emailVerified":false,       "disabled":false,       "metadata":{          "lastSignInTime":"Fri, 01 May 2020 10:55:51 GMT",          "creationTime":"Fri, 01 May 2020 10:26:12 GMT"       },       "customClaims":{          "admin":[             "xyz"          ]       },      },    {       "uid":"T9FucO2XqHXKh8SvfQMd8uPuQ8i1",       "emailVerified":false,       "disabled":false,       "metadata":{          "lastSignInTime":"Thu, 30 Apr 2020 05:47:30 GMT",          "creationTime":"Thu, 30 Apr 2020 05:47:30 GMT"       },       "customClaims":{},       "providerData":[          {             "uid":"+917827831148",             "providerId":"phone",             "phoneNumber":"+917827831148"          }       ]    } ]   I am trying to get the objects which contains the customeClaims ==={}  here is my tried solution but when i am using this i am getting an empty array[]  const result = data.filter(doc =>{     return (doc.customClaims==={}) }) console.log(result)


Check and fix all files from Debian packages.

I've been having some memory corruption issues, causing random crashes, but I've fixed them now. However, I'm concerned that some packages may be corrupted (as naturally any package update has to go through memory before it's written to disk).  Is there any way to automatically checksum all of the package files on a Debian system, and compare them to the archives, and if they're incorrect, update them?


Error JavaFX, I think its onlye a configuration or Java version problem

Error JavaFX, I think its only a configuration or Java version problem. What do you think? This is the error: What is happening? Exception in Application start method java.lang.reflect.InvocationTargetException     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)     at java.lang.reflect.Method.invoke(Method.java:498)     at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:389)     at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:328)     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)     at java.lang.reflect.Method.invoke(Method.java:498)     at sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:767) Caused by: java.lang.RuntimeException: Exception in Application start method     at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)     at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$159(LauncherImpl.java:182)     at java.lang.Thread.run(Thread.java:748) Caused by: java.lang.NullPointerException     at it.wunder.app.wmed.main.Utilities.getSelectedScaleName(Utilities.java:97)     at it.wunder.app.wmed.main.WMed.prepare(WMed.java:65)     at it.wunder.app.wmed.main.WMed.start(WMed.java:29)     at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$166(LauncherImpl.java:863)     at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$179(PlatformImpl.java:326)     at com.sun.javafx.application.PlatformImpl.lambda$null$177(PlatformImpl.java:295)     at java.security.AccessController.doPrivileged(Native Method)     at com.sun.javafx.application.PlatformImpl.lambda$runLater$178(PlatformImpl.java:294)     at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)     at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)     at com.sun.glass.ui.win.WinApplication.lambda$null$152(WinApplication.java:177)     ... 1 more Exception running application it.wunder.app.wmed.main.WMed  Process finished with exit code 1  What should I do?


I've recently been introduced to the error function: $$\operatorname{erf}(z) =\frac{2}{\sqrt{\pi}}\int_0^z e^{-t^2}dt$$ Naturally, I wondered about the origin of its name: The error of... what? I'm so used to uncertainty analysis in scientific experimentation that my mind went there first. It seems like the name sprung up in the context of statistical analysis. Here's what I found on :  In the course of the 19th century the function from the theory of errors appeared in several contexts unrelated to probability, e.g. refraction and heat conduction. In 1871 J. W. Glaisher wrote that "Erf(x) may fairly claim at present to rank in importance next to the trigonometrical and logarithmic functions." Glaisher introduced the symbol Erf and the name error function for a particular form of the law as follows: As it is necessary that the function should have a name, and as I do not know that any has been suggested, I propose to call it the Error-function  ... ("On a Class of Definite Integrals, Philosophical Magazine, 42, 1871, p. 296)  But this quote sounds like Glaisher arbitrarily picked the name. He must have had some motivation in dubbing it error. Anyway, what does error represent? Does this measure some deviation from the related Gaussian integral from $\int_0^\infty$? EDIT The link provided by Dilip is useful, yet still did not explain the depth of this name to me. I am wholly unfamiliar with probability and error theory - where $erf(z)$ seems to have arisen - so excuse me if the answer should have been more obvious. (In fact, error theory sounds vaguely alien to me.) Is the function just commonplace in error theory, and for that reason named $erf$? This reasoning just seems a little, well, lackluster to me, but maybe it's true. Does $erf$ have a specific role that reflects its name?


Use grep to find content in files and move them if they match

I'm using grep to generate a list of files I need to move:  grep -L -r 'Subject: \[SPAM\]' .   How can I pass this list to the mv command and move the files somewhere else?


How are new people created from the DNA of an aged person. i.e. Why are we young?

The question "why do we age" has been asked numerous times. But why are we young? The cells of the adult human being are an age (time>0), but how can old cells create new cells that are younger than themselves?  I.e, how are young people made from the cells of old people?  I realize that senescence, the act of a cell aging, has to do with the shortening of telomerase over time which puts a limit (the Hayflick limit) on the life of an autosomal cell. So in theory, because cells only make direct copies of themselves but the telomerase shortens with every division, each new daughter pair would be as old as the parent and would continue aging. But how come new people start senescence at time t=0?


Let G be a non abelian group then its order can be...

Let $G$ be a non abelian group.Then , its order can be:(which will be correct options)    $(1).~25$ $(2).~55$ $(3).~125$ $(4).~35$   I know ,what is abelian group,also I know order of a group.but I can't ans this question. Please help me.


Increasing Emission without Increasing Brightness

How would I go about increasing the strength/distance of an Emission texture without the texture getting brighter in Blender Cycles?  Lets say I take the following texture and make a light mask out of it. I then mix them equally with the Texture as a Diffuse BSDF and the Mask as an Emission.    With the Strength set as 1.000 the texture looks ok but I feel it just isn't bright enough. But if I set it to something higher (like 100.000) the texture gets oversaturated.    Is there some way I can have the light emit to infinity if I so pleased, yet have the texture remain the same brightness in Cycles?


Has Mjolnir ever been used "as a tool to build"?

In the MCU movie Thor, Odin says that Thor's hammer "has no equal as a weapon to destroy, or as a tool to build."  We see it used as a weapon plenty of times throughout the MCU's run, but I don't think I've ever seen it used as "a tool to build."  Has it ever been employed as a tool, in the movies or the comics?


I have an app to deploy in production that uses 'honor system' security. That is, all users connect to the DB using a SQL user/passwd credential and the app manages permissions itself. The latter part doesn't bother me as much as the fact that the connection object contains embedded credentials and can be copied around freely. I'm try to find some way to limit connections to a more limited set of clients. I can create firewall rules to limit by IP, of course. Is there any way to 'prequalify' SQL logins either by Machine account or domain membership?


I'm using a full 2GB USB. Now it is automatically write-protected. I can't delete, add file or format the USB. I always safely remove before removing it. I have tried both editing regedit and diskpart as instructions on the internet. I have also scan it with a trusted antivirus. Please help me. I'm thinking of a person blocking my USB for money :(. Thanks for your help. P/s: the drive's type is currently FAT.


I have a trigger named  DueDiligenceListHandler on our Stage instance which according to Developer Console has lines within a catch block which I can't seem to cover using my test class named TestDueDiligenceListHandler  I specifically tried to test the exception  Is this one of those situations? If not, how can I move forward and get the lines within my catch block for this trigger covered by my test class method?


javascript clicking a html button does nothing

I have a simple bootstrap html layout setup, which contains 2 buttons #add and #take. When calling their functions before from the $(document).ready function, everything works, but since I will need to reuse the functions anyway I decided to put them outside.  Now when I click the button nothing happens. Can somebody please tell me what I'm doing wrong?    html:

       Session length:       25 min       <button id="add" class="btn btn-info">+</button>       <button id="take" class="btn btn-info">-</button>

25:00

       <button id="start" class="btn btn-success">Start</button>       <button id="reset" class="btn btn-danger">Reset</button>

   js:  function addMinute() {   time + 60; }  function removeMinute() {   time - 60; }  function updateSession(a) {   $(".session").empty();   $(".session").append(a + " min"); }  $(document).ready(function() {    var time = 1500;    $("#add").click(function(time) {     addMinute();     updateSession(time);   }) //end add.click }); //end document.ready


Conserving Labels during Export to CAD in ArcGIS for Desktop?

I can export files to cad (i use ArcGIS 10.2), but the converted file does not involve labels,.  Then i tried to use another option, right click to layer name in Table of Contents then click Convert Labels to Annotation then export to cad but still same problem.  The result is a useless vector data without labels, so how can i export a layer to cad with labels?


How to downgrade from ubuntu 19.10 to 18.04

I recently upgraded to ubuntu 19.10 from 18.04 using  do-release-upgrade. But now I realize that the new version consumes a lot of system resources and doesn't work properly on my machine. I want to go back to my previus version. How can I do that.


Does it matter which way named functions are declared?

I see named functions exampled this way:  var clearClick = function() {     // do something }   ...and then used for binding like so:  $("#clear").bind(click, clearClick);   ...or with the "shorthand" methodology thus:  $("#clear").click(clearClick);   But why not use a more "normal" (similar to other programming languages) construct like this:  function clearClick() {     // do something }   It works the same, doesn't it? Is there any disadvantage to defining functions in this traditional way? Is the previous way just jQuerians flaunting their newfangledness?


We want to predict Y based on some function of X, i.e., Y_hat = f(X). How can we show that the conditional expectation f*(X) = E(Y|X) is the mean-square optimal predictor, i.e., the function f* solves the minimization problem below? min E{[Y - f(X)]^2} Here the unrestricted mean-square optimal predictor is the conditional mean.


(Excessive) login prompt expects my old email even though it's long changed

I opened a superuser.com link today, and found myself not-logged-in. Already a bit suspicious. Anyway, I enter my email and password at the login prompt - and it fails. I enter my old email, which changed months ago, and I can login. I navigate to my profile's email settings - and of course I see the new email, only. Questions:  Why doesn't the email change effect all relevant accounts and login prompts? Where do I go and change my email for those login prompts?


What different between [[0] * n for i in range(n)] and [[0] * n] * n]  I have this code:  def matrix_decomposition(a):     n = len(a)     b = [[0] * n for i in range(n)]     c = [[0] * n for i in range(n)]     for j in range(0, n):         b[j][0] = a[j][0]         c[0][j] = a[0][j]/b[0][0]     for i in range(1, n):         for j in range(1, i+1):             b[i][j] = a[i][j] - sum(b[i][k]*c[k][j] for k in range(0, i))         for j in range(i, n):             c[i][j] = (a[i][j] - sum(b[i][k]*c[k][j] for k in range(0, i))) / b[i][i]     return b, c   and if I replace [[0] * n for i in range(n)] on [[0] * n] * n I get this error:     Traceback (most recent call last): File   "C:/Users/Noctus/PycharmProjects/lab3/matrix.py", line 46, in    [7, 22, 70, 149] File   "C:/Users/Noctus/PycharmProjects/lab3/matrix.py", line 27, in   matrix_decomposition c[i][j] = (a[i][j] - sum(b[i][k]*c[k][j] for k in   range(0, i))) / b[i][i] ZeroDivisionError: float division by zero   in 46 line I have:  b, c = matrix_decomposition([         [1, 2, 3, 4],         [2, 7, 21, 26],         [4, 13, 43, 88],         [7, 22, 70, 149] ])


I am a senior in high school and I am studying cystic fibrosis.   I don't quite get the function of the CFTR gene as this is my first time dealing with this type of heavy scientific  info.  I had searched up its function on a website like this:    By reading the gene functions section, I learned that CFTR regulate the formation of a chloride channel, changes the regulation of other transport pathways (i.e increase sodium ion absorption in sodium ion absortion). At the same time it also regulate the chloride-coupled bicarbonate receptor. And that is about all I got from that section.    I would greatly appreciate if someone can summarize all the functions of the CFTR gene listed in layman terms (i.e grandma language)  and also explain to me why decreased  chloride channel leads to thicken mucus or increase sodium ion absorption leads to CF Symptoms. In addition I would also appreciate it if someone can tell me does decreased CFTR gene function also lead to other diseases on top of Cystic fibrosis.  Thanks


Which of the two books is suited for a student looking to learn how to write proofs? I have a working knowledge of calculus and linear algebra but I'm not good at writing proofs. My intention is to learn proofs in general, not necessarily for the two.       The reason I ask is that the latter is suggested on a highly voted question here but the former has a more apt name. The reviews aren't helping. Please don't suggest books other than these.


Oven Temperature: How to be sure the selected temperature is correct.

I suspect that my - fairly new - oven gets too hot, so I bought an oven thermometer, which confirmed this.  So I called the supplier.  They say that in order to obtain the correct actual  oven temperature, for any setting, you take the highest reading on the thermometer, and the lowest, and then divide both readings.   Is this correct?


What is the command to get block that you can place it in gamemode 2?

How do I get a block like a pressure plate, that allows me to place it in Adventure Mode (gamemode 2), because you can't normally place blocks?


Two book series about humans grown from DNA sent from earth who are seeking their origins

There were two books in the set. Humans are living in another galaxy within an alien culture. They discover that they were grown by this other species based on DNA code beamed from Earth ages before. A group of humans are eventually given permission to make their way back to earth. During their travels they piece together the history of humanity and what befell them.  I have searched every author I can think of but can't find them. It feels so much like a Baxter novel but I don't see anything by him.


Need a good handbook of ubuntu as because i am a beginer in this subject

Can anyone give me good hand book links of ubuntu?


Calculating resistance for zener diodes?

I am an electronics student, and I was set some homework online. I am not having trouble with the question itself but the theory. It says that the current through the resistor is the same as the maximun current that the diodes can safely handle, but as you can see, there are (\$V_{out}\$) volts being dissipating to the right, and a minimum required current going through the diode to maintain consistent voltage.  The thing is, how could the current through the resistor be the same as the current through the diode, as \$Voltage=J/C\$, or, joules per coulomb, so that means there must be some energy carried by the coulombs, and ultimately, some electrons. But then this is contradictory, wouldn't the current going through the resistor be the total current, the current dissipated to the right and current through the zenor? Or... is it that there isn't, then, any current passing at \$V_{out}\$? and it doesn't represent voltage being dissipated? I cant wrap my ahead around it...


Prove that if ${s_n}$ is bounded and monotonic, then $t_n =(s_1 + \cdots+ s_n)/n$ converges to the same limit as ${s_n}$

I have already shown that $t_n$ is convergent using the monotonic convergence theorem. Let's say ${s_n}$ converges to $L_1$ and ${t_n}$ converges to $L_2$. How can I show that $L_1$=$L_2$?


From SEO perspective: Are there any reasons NOT to switch to HTTPS-only for a homepage?

I have a decision to make:  Option 1: Require HTTPS only on sensitive pages, and support both HTTP and HTTPS on other pages  Option 2: Require HTTPS on all pages without exclusions.  From security perspective option 2 would be the best choice of course. What I want to know is what this does to search engine ranking. Will HTTPS-only connection have any negative effects on SEO?


Positive harmonic function with harmonic reciprocal must be constant

Let $f(z)$ be a positive harmonic function on the unit disk such that $\frac{1}{f(z)}$ is also harmonic. Show $f(z)$ must be constant.


Square root argument of a complex number.

How could I compute the argument of the following complex number: $$\lambda=\sqrt{x^2-y^2+m^2-2isxy}$$ where, $s=\pm1,\,\,m\in\mathbb{R}$. I know for number in algebraic form $z=a+bi$ it's easy, just do, $arg(z)=\arctan\left(\dfrac{b}{a}\right)$ but unfortunately this is not the case. Thank you in advanced.


UK transit visa (Sri Lankan holding Schengen student visa )

I'm a Sri Lankan national. I'm currently doing my M.Sc. in Norway. So I have a Schengen Student visa (temporary resident permit) which I renew every year.  My question is that if I want to transit via London Heathrow without entering the UK do I need a transit visa? Because the www.gov.uk site does mention that there are exemptions for people with long stay visa (Category D Visa) in EEA countries. I couldn't find any information about my specific situation. Is my Schengen Student visa (temporary resident permit) a category D visa which qualifies for transit in the UK without a visa?  Thank you!


Is the change in orbital of an electron the only way a photon is created

I would like to know if there are any other ways in which photon's are being emitted other than in the case an electron's orbital around a nucleus changes.


I'm running Apache2 in a docker container, and want to write nothing to the disk, writing logs to stdout and stderr. I've seen a few different ways to do this (,  ) but these seem like hacks. Is there no way to do this by default?   To be clear, I do not want to tail the log, since that will result in things being written to the disk in the container.


Kinetic energy of disk rotating around axis parallel to the one through its center

Given the situation shown in the figure below. A thin disk with mass m and radius r is rigidly connected to one end of a massless rod with length l at its centre, with the other end of the rod connected to a fixed point O and able to pivot freely around the fixed point, without friction. The disk is lifted to a certain $\theta_0$, and then released from rest.  I'm wondering how, given this setup, one might calculate the kinetic energy of the disk when the centre of the disk is at its lowest point (or perhaps how to retrieve velocities using laws of energy). Namely, I was taught the kinetic energy of a simple system or body may be described as  $$E_k=E_{k,translational}+E_{k,rotational}=\frac{1}{2}m||\vec v||^2+\frac{1}{2}I_O||\vec\omega||^2$$  where:  $m$ is the mass of the body,  $\vec v$ is the linear velocity vector of the centre of mass,  $I_O$ is the moment of inertia around the axis of rotation,  $\vec \omega$ is the angular velocity vector.  One could perhaps use some simple trigonometry to express the initial potential gravitational energy (with the lowest height of the centre of mass set to a height of 0, for example), and use conservation of mechanical energy to then equate said amount of potential energy to the amount of kinetic energy when at lowest height.  All that seems to make sense when the disk is rotating around its centre, and translating at the same time. However, I'm having a hard time deciding whether or not this system would be describing "linear motion" with a linear velocity, when the centre of mass is at its lowest point. By the parallel axis theorem, we can say that for this disk, $I_O=I_C+m\:d^2=\frac{1}{2}m\:r^2+m\:d^2$, where d is the perpendicular distance between the axis of rotation through the centre of mass parallel to the axis of rotation, and the actual axis of rotation through O.   Thus, from what I understand, the disk is just rotating around an axis through O, but ... wouldn't that mean this is pure rotation, without translation? This seems counter-intuitive to me, but at the same time, if this isn't pure rotation, then I would say it is pure translation, as if the centre of mass were moving along a circular and frictionless rail. Both interpretations give different results, which cannot be correct. For all I know, the disk's kinetic energy could be a combination of both!   As a follow-up: say the disk were able to spin freely around its centre as well, and it were given a certain angular velocity $\omega_0$ before being released. How would the rotational kinetic energy differ, in that case? Both the disk's rotation and revolution would have to be taken into account, but here also, it doesn't seem obvious how exactly.


If $X \perp Y$ and $X+Y \in L^1$ then $X,Y \in L^1$

Suppose $X,Y$ are independent random variables and that $X+Y \in L^1$. How can I show that $X,Y \in L^1$.  The theorem obviously fails if independence is left off, but I don't see how to use it. Intuitively, if $X$ failed to be in $L^1$, then it is big somewhere, and the independence of $Y$ should says that $Y$ can't selectively cancel out $X$ where $X$ is big.


Teaching Google to Show a Menu for an Angular App?

If we Google "Panera" google shows Panera Bread as the top ranked result and below the description there's things like "Menu", "Locations", etc. How do we get these rendered for an Angular App that only performs client side rendering?


How to apply thickness XYZ to this spiral not a

I have used the screw modifier to create a spiral, but after finishing and applying the modifier, I realize that I did something, and now my spiral is only a line. There was a question recently closed that sounds like this, but I am asking if there is a way to apply something like a lattice to it to make a 3D mesh from it. This is what I am trying to fix: File here:


! LaTeX Error: File `adjustbox.sty' not found on Ubuntu 10.04.2

I have install $ sudo apt-get install texlive-full on Ubuntu 10.04.2 but when I run I got this error about adjustbox.   ! LaTeX Error: File `adjustbox.sty' not found   Is there anyone know how to install/fix this error.


Is there an easy way to limit user bandwidth usage?

Is there an easy way to limit user bandwidth usage to say 10kpbs? Other users should not be affected. The best I've found is tc, but it seems way too complicated to do such a simple thing.


What version of Ubuntu would be good for a HP 1110nr mini netbook 1g memory 160g processor.


Annihilator of a maximal ideal in a polynomial ring[updated]

Let $R = k[x, y]$ be the polynomial ring in two variables and $I$ an ideal of $R$ such that $R/I$ is finite dimensional. I wonder if the following statement is correct?   If $\mathfrak{m}$ is a maximal ideal in $R/I$, then its annihilator in $R/I$ is nonzero.   Here, I assume $k$ is algebraically closed. Thanks!


Install Windows10 after Ubunutu 16.04 on SSD

Config : MSI laptop with FreeDos  I'd like to know if i can install Ubuntu first, then Windows 10 later on a SSD ? With previous versions of Bios and Windows, it was impossible, and now ?  Thanks


public class llearning1 {      public static void main(String[] args) {          String text = "is";         String x = "what is good";         String y[] = x.split(" ");          for (String temp: y) {              if (temp == text) {                 System.out.println("found");             } else {                 System.out.println("nothing");             }         }     } }   output:   expected : code should display "found"  but it is displaying "nothing"


I have an iPad 2, it is not charging at all. What can I do? I have tried a different charger,

Everything I need to say is mentioned in the question.


How to insert subitem into list without breaking layout?

What I want to see in final (i.e. Outer begin x-pos is same as outer end x-pos, top & bottom margins for inner approx. equal):        What I really see (too large v-space before inner) as picture:        Live example:     Outer begin   inner   outer end     Code for this:  * Outer begin  * inner   outer end   Is it possible to reach desired view using an existing markdown syntax on Stack Exchange sites?  Is it a bug in markdown when I see too large v-space?  As it turned out the android-app displays the list as necessary:


What is the physical meaning to vanishing Ricci scalar $R=0$ of a metric in general relativity? Note that this is not the same questions as the geometric meaning of $R_{\mu\nu}=0$ which has been asked before.


Why can I only receive a special loot table from a chest using /give and not /summon?

I tried the custom loot tables here:                                (with his website:  ).  I successfully obtained my chest with the custom loot using:   /give @p minecraft:chest 1 0 {BlockEntityTag:{LootTable:"mctools:chests/loot_table"}}   The problem is that I want to summon the chest instead of giving it to the player. I tried the command:   /setblock ~1 ~ ~ chest 0 replace {BlockEntityTag:{LootTable:"mctools:chests/loot_table"}}   The chest did place, but when I opened it, the chest was always empty. Why can't I retrieve my loot this way? And if possible, how can this be done?


Why do Google search results include pages disallowed in robots.txt?

I have some pages on my site that I want to keep search engines away from, so I disallowed them in my robots.txt file like this: User-Agent: * Disallow: /email  Yet I recently noticed that Google still sometimes returns links to those pages in their search results.  Why does this happen, and how can I stop it? Background: Several years ago, I made a simple web site for a club a relative of mine was involved in.  They wanted to have e-mail links on their pages, so, to try and keep those e-mail addresses from ending up on too many spam lists, instead of using direct mailto: links I made those links point to a simple redirector /  script running on my own site.  This script would return either a 301 redirect to the actual mailto: URL, or, if it detected a suspicious access pattern, a page containing lots of random fake e-mail addresses and links to more such pages.  To keep legitimate search bots away from the trap, I set up the robots.txt rule shown above, disallowing the entire space of both legit redirector links and trap pages. Just recently, however, one of the people in the club searched Google for their own name and was quite surprised when one of the results on the first page was a link to the redirector script, with a title consisting of their e-mail address followed by my name.  Of course, they immediately e-mailed me and wanted to know how to get their address out of Google's index.  I was quite surprised too, since I had no idea that Google would index such URLs at all, seemingly in violation of my robots.txt rule. I did manage to submit a removal request to Google, and it seems to have worked, but I'd like to know why and how Google is circumventing my robots.txt like that and how to make sure that none of the disallowed pages will show up in their search results. Ps. I actually found out a possible explanation and solution, which I'll post below, while preparing this question, but  in case someone else might have the same problem.  Please do feel free to post your own answers.  I'd also be interested in knowing if other search engines do this too, and whether the same solutions work for them also.


I am trying to delete my linux-swap partition /dev/sda5 and allocate the free space to /dev/sda6.  But when i try to delete sda5 GParted gives an error "You have to umount sda6". But i can not umount sda6. I gives me the error "umount: /: target is busy" If i reduce the size of sda5 i can not allocate the unallocated space to sda6.  Can anyone give me some advice on how to do this the right way?  I have a multi-boot system with windows and Linux. (Grub2)


Is blocking query commands enough to prevent SQL injection?

I'm a beginner in the field of databases, and I'm about to understand, how free text inputs for queries might be used to compromise a database via SQL injection.  Actually,  sums it up perfectly:    This certain comic implies that if I don't allow users to form ANY kind of input that contains SQL commands (like DROP, UPDATE, INSERT INTO, etc.) then "illegal" SQL queries can't be done.  Is there anything I miss? Or am I right?


There are a lot of questions which have (often enough) complex and good answers in comments, which should really be posted as answers.  A good example is here: . Virtually all of the questions in "assembly" listed when using "unanswered" have answers provided via comments.  Now I was reading  and notice this comment:     More than that... in case you ask them to post as answer and they don't do that within a day or so, just post your own answer and mark accepted. Case solved. :) –  Sha Wiz Dow Ard   And I'm unsure if this was just a joke or meant seriously.  On the one hand, SO should provide answers, and it would be helpful, if the answer is provided in comments, if it were summarized in a real answer. On the other hand, I would feel a bit like a rip off (is this the proper term?) if I would do this from somebody else's comments and possibly even get the rep for it.


Suppose a given series ($\sum_{n=0}^{∞}a_n)$ converges absolutely. Must ($\sum_{n=0}^{∞}(a_n^2) )$converge?

How would one go about answering this question? Is there an example sequence we can use? Our TA suggested something about some value k for n that would make |a_n| >= a^2_n


How to prove that $\sum_{i=0}^n\binom{n}{i}^2 =\binom{2n}{n}$

How can I prove that $\sum_{i=0}^n\binom{n}{i}^2 =\binom{2n}{n}$  Thanks in advance!


Variables in bash seq replacement ({1..10})

Is it possible to do something like this:  start=1 end=10 echo {$start..$end} # Ouput: {1..10} # Expected: 1 2 3 ... 10 (echo {1..10})


Does there exists a "maximal" convergent series?

My question is as follows: Does there exist a sequence $(a_n)$ of non-negative real numbers such that $\sum_{n=1}^\infty a_n < \infty$, but for any sequence $(b_n)$ of non-negative numbers with $b_n \to \infty$, we have $\sum_{n=1}^\infty a_nb_n = \infty$? To me this seems to be asking if there is in some sense a "maximal" convergent series, as any "bigger" series diverges, where "bigger" means pointwise multiplied by some unbounded non-negative sequence. Thus my first thought to solve this was Zorn's lemma. I tried to define an order $\preceq$ on the space of all convergent non-negative sequences by saying $(x_n) \preceq (y_n)$ if there exists an unbounded sequence $(b_n)$ of non-negative numbers such that $y_n = b_nx_n$ for all $n$. But this order is not reflexive so we cannot use Zorn's lemma. I did manage to prove a weaker version, namely that if $(b_n)$ is any unbounded non-negative sequence then we can find a non-negative sequence $(a_n)$ with $\sum_{n=1}^\infty a_n < \infty$ and $\sum_{n=1}^\infty a_nb_n = \infty$, and I can easily extend it to finitely many $(b_n)$, but have not been able to extend it to infinitely many (i.e. for all unbounded sequences). Any suggestions are appreciated!


I still don't get why Misfits-Simon wanted to travel back in time in the first place

So future-Simon goes back in time and becomes the superhoodie in order to save the gang and to make Alicia fall in love with present-Simon.   But I don't get it. Why on earth would the very first future-Simon travel back in time? Because that Simon didn't have a future-Simon to make Alicia fall in love with him? So Simon would still be kinda shy and not superhoodie, so it does not make sense that he should start the loop.  I know it's a loop with no beginning and end, but still - it's quite unsatisfying to think that "poof" - suddenly you have a future-Simon who already has experienced love with Alicia to start the loop. Please help :)


I have been looking for ways to full screen my Git terminal screen on windows.  I tried tweaking the property settings but no luck.  I found few crazy hacks online , but could not get it to work! :(  I am at a loss to understand why I can't find an easy way to accomplish such basic thing.


A recipe calls for buttermilk but I don’t want to go to the store just for that. Can I make my own


What is the word for reserving something for yourself before others do?

In English-speaking TV shows, characters sometimes say something similar to dips to say to other people they are taking something for themselves before others do.  Neither Google, Wiktionary or Urban Dictionary give positive results for this so the word may be misspelled.  What is the word and what is its origin?


How do I enable a particle system for text?

I am using blender for the first time, and i am watching a tutorial to create an animated name, but when it was time to use the particles system, i didnt have the option enabled in my blender page, how can i install it or enable it on my screen?


Finding $\mathrm{Var}(N)$ if $N=\inf\{n\ge1:\sum_{i=1}^nX_i>1\}$ where $X_i$'s are i.i.d Exponential variables

Suppose $X_1, X_2, X_3, \ldots, X_n$ be independent and identically distributed random variables having an exponential distribution with mean $\frac{1}{\lambda}$.  If $S_n = X_1 + X_2 + \ldots + X_n$ and $N = \inf\{n \geq 1: S_n > 1\}$, then what would be the value of $\mathrm{Var}(N)$ ?


when i use command sudo apt-get install git it's return below erorrs and it's return for any application to install below :   Setting up util-linux (2.25.2-4ubuntu3) ... update-alternatives: error: cannot stat file '/usr/bin/nodejs': Too many levels of symbolic links dpkg: error processing package util-linux (--configure):  subprocess installed post-installation script returned error exit status 2 Errors were encountered while processing:  util-linux E: Sub-process /usr/bin/dpkg returned an error code (1)   update with sudo apt-get update not working and report below erorr  Fetched 7,032 kB in 5min 32s (21.2 kB/s)                                        W: Failed to fetch http://ppa.launchpad.net/paullo612/unityshell-rotated/ubuntu/dists/vivid/main/binary-amd64/Packages  404  Not Found  W: Failed to fetch http://ppa.launchpad.net/paullo612/unityshell-rotated/ubuntu/dists/vivid/main/binary-i386/Packages  404  Not Found  E: Some index files failed to download. They have been ignored, or old ones used instead.   how can fix it ?


Sometimes, a question is perfectly solved by suggestion or actual resolution given in "comments" under it. In such case, how to mark that answer (comment) as "Accepted Answer"? Due to this, the question remains unanswered even if solution is provided in comment.


If $R$ is a ring and $M$ be any maximal ideal with $a\notin M$, then there exists $q\in M$ and $s\in R$ such that forall $r\in R$ $r=sar+qr$

If $R$ is a ring and $M$ be any maximal ideal with $a\notin M$, then there exists $q\in M$ and $s\in R$ such that forall $r\in R$ we have $r=sar+qr$. Also show that this is true only when $M$ is maximal ideal. I am assuming $R$ is commutative and $1\in R$. Please help me. I am unable to proceed.


Here is an interesting piece of code that my fellow team members were just having a slightly heated discussion about...    Dim fred As Integer    If True Then fred = 5 : fred = 3 : fred = 6 Else fred = 4 : fred = 2 : fred = 1   After executing the above code snippet, what is the value of fred?  Try not to cheat and debug the code.  This is a highly contrived code example that started out as an example of using the colon with an If statement, but then someone decided to take it upon themselves to proffer a result for fred.  UPDATE: I would not normally write code like this and this snippet only serves as an example. As it so happens, this question originated from a discussion involving the creation of a coding standards document for our team.


Object in edit mode moves with giant step, can't make precise adjustments

I'm trying to edit a mesh in blender, but when I try to move a vertex it moves by a set amount that is ridiculously far from the original position, and there's no ability to place it at any point in between. This happens regardless of whether or not proportional editing is being used.


Complement of any finite set in metric space.

I am asked to show that in a metric space the complement of any finite set is open. That means I have to show that finite set is closed. I just tried to cope up with this problem using closure definition but dont know whether my approach is correct or not.  I know that the union of $A$ and $A'$ (the set of all interior points of $A$) comes to be $A$ if I take $A'$ to be empty or $A'$ to be $A$, so that I get  (closure of $A$) $ = A$ and by using the statement (closure of $A$)$=A$ iff $A$ is closed, I get the proof done. My question is can I apply this definition here. Sorry if I am asking something weird. I am just asking whether or not should it is absolutely proper to use that specific definition, thats all. aso, I think my question has some additional questions about using the definition.


Why doesn't "need" take a "to" infinitive in some cases?

In a book of Alexander McCall Smith I found this phrase:     No historical novelists need apply.   Why isn't it this with a  to for the infinitive?     No historical novelist need to apply?


Is $2^\sqrt{2}$ is rational or irrational?

There are many popular problems on irrational power rational. A very interesting read is . And there are many specific examples where rational power irrational is rational (e.g. $2^{\log_2(3)}$). But what about $2^{\sqrt{2}}$? Is it rational or irrational?


When does $\sum\frac{1}{(n\ln n)^a}$ converge?

I've to investigate when does $\displaystyle \sum\frac{1}{(n\ln n)^a}$ converge?   For $a>1$, I used the limit comparison test as $\displaystyle \frac{\frac{1}{(n\ln n)^a}}{\frac{1}{n^a}} \to 0$ as $n\to \infty$ so that $\displaystyle \sum\frac{1}{(n\ln n)^a}$ converges together with $\displaystyle\sum \frac{1}{n^a}$ and for $a\le\frac{1}{2}$ notice that $\displaystyle \sum\frac{1}{(n\ln n)^a}>\sum \frac{1}{n^{2a}}$ and since RHS diverges we can see $\displaystyle \sum\frac{1}{(n\ln n)^a}$ diverges . But what happens if $a\in(\frac{1}{2},1)$? Or is there any other method to cover these cases on one step?


Convergence and limit of $a_{n+1} < \frac{a_n+a_{n-1}}{2}$

Suppose $(a_n)$ is a sequence such that $\forall n: a_n \in (0,1)$ and $a_{n+1} < \frac{a_n+a_{n-1}}{2} (*)$.  (1) Is it true that $a_n$ converges?  (2) Find all possible limits of such sequences  Attempt  Let $k_{n+1}=\frac{a_{n+1}}{a_n}$. Then $(*)$ becomes $k_{n+1} < 0.5 + 0.5\frac{1}{k_n}$. So if $a_n$ was much bigger than $a_{n-1}$, then $a_{n+1}$ is smaller than $a_n$. Need to show that $\lim_{n\to\infty}k_n=1$ or $\lim_{n\to\infty} a_n = 0$. Got stuck  Edit  This question is a 100% duplicate of   Another similar (but not exactly same) question is


I have below code which does find and replace. I have tried to debug the code but nothing that i found helped.  import pandas as pd import re  ##### Build test set of sentences to be cleaned #dataframe to be cleaned dat = pd.read_csv("H:\\Find Replace Tool\\Find_Replace_in_this_v1.csv") #clean dat.currentTitle=dat.currentTitle.str.replace(r"[^a-zA-Z0-9`~!|@#%&_}={:\"\];<>,./. -]",r'') dat.currentTitle=dat.currentTitle.str.replace('\s+', ' ') dat.currentTitle=dat.currentTitle.str.lower() #create list of column test_sentences = dat.currentTitle.tolist()  ##### Create search and replace patterns #list element of of each row like this [('word0','repl0'),('word1','repl1'),('word2','repl2')] #dataframe with lookup dat2 = pd.read_csv("H:\\Find Replace Tool\\Find_Replace_v1.csv")  patterns = list(zip(dat2.keyword, dat2.lookupId)) #convert list into dictionary patterns_dict = dict(patterns) #for value of first and second column in the list: return (first_column with regex) and second_column patterns_comp = [ (re.compile("\\b"+search+"\\b"), repl) for search, repl in patterns ] del dat2  def replace4( sentences ):     #pass dictionary index to get value. not sure what is done here     pd = patterns_dict.get     #m could be group of all regex matches     def repl(m):         #group() is used for assigning out of many regex, which one you want to use         w = m.group()         return pd(w,w)     for n, sentence in enumerate( sentences ):         sentence = re.sub(r"\w+", repl, sentence)     dat['cleanedTitle'] = sentence  replace4(test_sentences)   When i execute this i am getting below error. What could be cause and how do i fix it? I haven't found any solution yet  error                                     Traceback (most recent call last) <ipython-input-104-43c08b4ceffa> in <module>()       2 #for value of first and second column in the list: return (first_column with regex) and second_column       3 for search, repl in patterns: ----> 4     a = (re.compile(r'\b'+ search + r'\b'), repl)       5     #if j <5:       6         #print search,repl  c:\python27\lib\re.pyc in compile(pattern, flags)     192 def compile(pattern, flags=0):     193     "Compile a regular expression pattern, returning a pattern object." --> 194     return _compile(pattern, flags)     195      196 def purge():  c:\python27\lib\re.pyc in _compile(*key)     249         p = sre_compile.compile(pattern, flags)     250     except error, v: --> 251         raise error, v # invalid expression     252     if not bypass_cache:     253         if len(_cache) >= _MAXCACHE:  error: unbalanced parenthesis


Does entropy increase or decrease as our Universe is expanding?

Scientists say that entropy of our universe is increasing as it is expanding and our universe is cooling down gradually from the time of its birth. If something is getting cooler and cooler, then how can it become more random (entropy increase) with the passage of time? According to laws of thermodynamics, at absolute zero temperature, the entropy is zero. That means as we go down and down to the temperature scale entropy must decrease, but why is it not happening in the case of our universe?


Is there anything to do during an 8 hour after-midnight layover in Dubai?

We are planning a trip with an 8 hour layover in Dubai spanning from 1am-9am. I am thinking about going to see the city, but is it worth it to do it given the very late night hours? Will at least the outside attractions accessible?   Will Burj Khalifa be visible in the middle of the night?  Will at least some of the malls be open?  Will there be anything to do at night?  I have seen other questions about layovers in Dubai (), but none of them is asking about a night-only stay.


I am working on binary classification problem, I try to evaluate the performance of some classification algorithms (LR,Decission Tree , Random forest ...). I am using a 10 fold cross-validation technique (to avoid over-fitting) with AUC ROC as scoring function to compare the performance of the algorithms, but I am getting a weird results with Random forest and AdbBoost, I have a perfect AUC_ROC score (i.e. =1) despite the fact that the Recall(TPR) and FPR of this algorithms are different from 1 and 0 respectively .


$f$ is continuous at $x_0$ if and only if $\forall n\in \mathbb{N}$, $a_n<x_0<b_n$, $\lim_{n\to \infty}[f(b_n)-f(a_n)]=0$

This is a question I picked up from Royden's.     Let $f$ be an increasing function on an open interval $I$. For $x_0\in I$ show that $f$ is continuous at $x_0$ if and only if there there exists two sequences {$a_n$}, {$b_n$} in $I$ such that $\forall n$, $a_n<x_0<b_n$, $\lim_{n\to \infty}[f(b_n)-f(a_n)]=0$   This is my attempt for the forward implication. Suppose $f$ continuous at $x_0$ and that for each pairs of  sequences {$a_n$}, {$b_n$} in $I$, $\lim_{n\to \infty}[f(b_n)-f(a_n)]\neq 0$. Then there exists some $\epsilon>0$ such that for each $N\in \mathbb{N}$ , there exists a $n>N$ such that $|f(b_n)-f(a_n)|\geq \epsilon$.  Also, there exists a $\delta_1>0$ such that $|f(b_n)-f(x_0)|<{\epsilon\over 2}$ and there exists a $\delta_2>0$ such that $|f(a_n)-f(x_0)|<{\epsilon\over 2}$ whenever $|b_n-x_0|<\delta_1$ and $|a_n-x_0|<\delta_2$. Notice that $$|f(b_n)-f(a_n)|=|f(b_n)-f(x_0)+f(x_0)-f(a_n)|\leq |f(b_n)-f(x_0)|+|f(x_0)-f(a_n)|<\epsilon$$ whenever  $|b_n-x_0|<\delta$ and $|a_n-x_0|<\delta$ where $\delta=$max{$\delta_1,\delta_2$}. We have arrived at a contradiction. Is this idea correct?


Are suffixes like Jr. and Sr. ever used to distinguish e.g. grandson and grandfather?

The most common Junior and Senior combinations are father and son, but what about in other contexts, such as grandson and grandfather (assuming that they have the same name)?


Extract Keys from list of dictionnary through function in Python

Let's say I have a list of dictionnaries call x. If I want to extract the keys and push them into a new list called y :  y = {k for d in x for k in d.keys()} y = {k for k in chain(*x)}   Now I want to do the same operation with a function. As I don't know the name of the list of dict in advance, I was thinking of using *args  def formatting(*args):         return {k for d in args for k in d.keys()}  x_list = formatting(x)   But doing this return AttributeError: 'list' object has no attribute 'keys'  When I passing the real variable name in the function, it's working...  What is the correct way of passing list of dict into a function ?


In basketball, can you score by bouncing the ball off the ground?

If a player slams the ball on the ground so hard that it bounces into the hoop, is that a valid goal?  (Bonus trivia question: has this occurred in a professional or collegiate game?)


why isn't positive terminal of a battery used for grounding?

i'm really confused by the concept of both conventional current and electron flow. Since electrons flow from negative terminal to positive terminal, shouldn't positive terminal be used for grounding?


Problem involving many squares and several variables.

Let $a, b, c, d, e, f$ be nonnegative real numbers such that   $a^2 + b^2 + c^2 + d^2 + e^2 + f^2 = 6$. $ab + cd + ef = 3$. What is the maximum value of $a+b+c+d+e+f$ ?.   I was thinking about somehow manipulating the numbers to get $\left(a + b + c + d + e + f\right)^{2}$, but I don't really know what to do.


Lost supplementary user groups for GUI login session

Ubuntu 16.04.5  Very weird situation - after Xorg crash, now every time when I login into Unity, my user account doesn't have it's system groups like adm, sudo, plugdev, fuse etc. But when I login on virtual console (Alt+F1) or over SSH - all my additional groups are there, as reported by id command.  Neither of /etc/group* or /etc/gshadow* files have changed, my user is still listed there in many system groups.  It looks like some systemd session parameters for GUI logins or lightdm cache files got screwed. But I have no idea where to start looking..  A lightdm log:  $ journalctl -au lightdm  -- Reboot -- systemd[1]: Starting Light Display Manager... systemd[1]: Started Light Display Manager. lightdm[3223]: pam_kwallet5(lightdm-greeter:setcred): (null): pam_sm_setcred lightdm[3223]: pam_unix(lightdm-greeter:session): session opened for user lightdm by (uid=0) lightdm[3345]: pam_succeed_if(lightdm:auth): requirement "user ingroup nopasswdlogin" not met by user "chm" lightdm[4867]: pam_ecryptfs: Passphrase file wrapped lightdm[3345]: pam_kwallet5(lightdm:auth): (null): pam_sm_authenticate lightdm[3345]: pam_kwallet5(lightdm:setcred): pam_kwallet5: pam_sm_setcred lightdm[3345]: pam_unix(lightdm:session): session opened for user chm by (uid=0) lightdm[3046]: Error writing to daemon: Bad file descriptor lightdm[3046]: Error writing to daemon: Bad file descriptor lightdm[3046]: Error writing to daemon: Bad file descriptor lightdm[3046]: Failed to write utmpx: Permission denied


Can we have a button that makes the answer box full screen?

I am typing this question in a box that has formatting options above and a little drag down thing on the bottom, that lets me expand the box if my question (or answer!) is long.   However, on some sites like Codegolf, questions can get very lengthy as they have to be specific about things like rules and giving example test cases. I myself have written a Codegolf challenge in the past and I noted that it was really annoying to have to drag the bar down a bunch of times so that I could easily see my whole response without having to scroll.   Can we have a 'fullscreen' button?   If you browse reddit and have RES installed you will see that when typing a comment or a post there will be a button for 'Big editor'; this is exactly what I am talking about. It also has a 'live preview' on the side, while here its below. It would be nice I guess if the preview was on the side.   This is not related to questions such as  and  where they are discussing horizontal scrolling in already posted answers; I'm talking about the process of answering a question.


Application for UK Visa rejected. How do I make my second application stronger?

I am a recent college graduate planning on a graduation trip to London and Scotland.   My tourist visa application was refused because of lack of evidence of my employment and evidence that I will be coming back to my country. Also because of a sudden uplift in my funds, they don’t believe my bank statement is a true reflection of my financial circumstance and that the funds in my bank statement might not be available for my exclusive use.  I believe I have sent an employment letter but no pay slip for the past 6 months. I’ve been working part time at my workplace for the past year and a half. Because I work part time, I do not have a fixed schedule. I work whenever I am free and sometimes it’s only once a month or even not at all because of school commitments so my income might not have been reflected in my 6-month bank statement. I had my finals mid this year as well as my graduation in September so I was only able to cover about 2 shifts at work over the last 6 months and wasn’t able to provide a pay slip.  However I was working more frequently from May to November 2016 and saved my income as well as pocket money from my parents, which amounted to about $4000. I transferred most of my income and deposited my cash allowances to someone else’s account for safekeeping as it was my plan to go on a graduation trip at the end of 2017 and didn’t want to risk spending the money. I only asked to transfer the money back to me before submitting my documents for my visa application. This explains the sudden uplift in my funds. I do see how it looks dodgy and would like to know how I can explain this to them? Would it help if I could provide payslips from 2016 that shows I was indeed getting an income that could amount to $4000?   My father has also offered to do a partial sponsorship of $3000 for my UK trip. He initially intended for the $3000 to be a surprise graduation gift, to be given before I leave for London. However since my visa rejection, he offered to write a letter declaring his role in sponsoring my funds. What should the letter contain and should there be any other documents to support this? Would this help in convincing them that I can in fact, support myself for the 17 days in UK?  As for evidence of return to my country, I am also on a Tuition Grant Scheme with the Government of Singapore which requires me to work in Singapore for 3 years upon graduation, which happened on the 3rd of September 2017. Failure to do so would make me liable for liquidated damages. I did not add this info/document as I wasn’t sure it was necessary. Would this additional info help my case? I also have a return ticket, fully paid!  Please advice on how I can make my application stronger. I am supposed to leave for London on November 30 2017 and have less than 2 weeks to get a visa. I will be travelling with a Friend who has also recently graduated.


Is it really forbidden to cross the Indian border with Indian rupee?

Last week I tried to exchange some Swiss Francs into Indian rupees. For that I visited a big bank and they told me that they have rupees but I'm not allowed to import any into India. Is this really true?  And if so, what's the reason behind such a law?  P.S. The bank also told me that in practice it isn't a problem if you take money below 200 Swiss Francs into the country.


I've been running Kubuntu for about a month now, still learning.  All of a sudden as of about two days ago, if I try to install or update software using Muon, it asks for the root password.  I'm assuming this is my administrative password, but that password won't work.  I know I'm typing it in correctly (case sensitive) and I haven't forgotten my admin password because I can log in to my laptop when I first turn it on using the same password.  If the administrative password is not the root password, then what is the root password?  I followed some directions online regarding booting in safe mode, but i can't get the passwd command to work.  I tried that twice and I keep getting an error message telling the password was not changed.  Then I don't know how to exit out of safe mode.  I kept hitting the escape key and that didn't work.  I ended up just powering off my laptop to get out of safe mode.


Ubuntu 18.04 WiFi not working after Upgrade/update on HP

Yesterday I updated my Ubuntu with the software update tool, after updating and restarting, my WiFi is no longer working. I'm running Ubuntu on a HP laptop. WiFi was working before the update, but now it isn't. I hade the same issue before and I fixed it, but now I forgot how I fixed it.


Extra colon in all silver and gold badges tooltip

Just noticed this in the  : (two examples)         It's in all sites, not just here on Meta. Bronze tooltip is OK.  After checking it appears that the tooltip for all silver or gold badges, anywhere, got extra colon:: can you please fix this? ::)


Understanding linear algebra in Ordinary Least Squares derivation

In ordinary least squared there is this equation (Kevin Murphy book page 221, latest edition)  $$NLL(w)=\frac{1}{2}({y-Xw})^T(y-Xw)=\frac{1}{2}w^T(X^TX)w-w^T(X^T)y$$  I am not sure how the RHS equals the LHS. Maybe my linear algebra is weak but I can't figure out how this happens. Can somebody point out how this happens. This is related to deriving the Ordinary Least squares equation where $\hat{w}_{OLS}=(X^TX)^{-1}X^Ty$


Which badges do not cause a notification for experienced users?

Yesterday, I have received two : Revival, and Self-Learner. However I was only notified of the Revival badge, because apparently the Self-Learner badge is not considered "".  What badges have their notification suppressed if the user has a 200-rep account somewhere on the Stack Exchange network, i.e. they won't trigger a new item in our achievements dialog?


I created a file long back named test.sh. Now I want to know when the file was created, not the modification time.  Which command I can use?  If I try stat test.sh:    File: 'test.sh'   Size: 7               Blocks: 8          IO Block: 4096   regular file Device: xxxx/12345r    Inode: 1769677     Links: 1 Access: (0761/-rwxrw---x)  Uid: (52898/  xxxx)   Gid: ( 1202/ xxxxx) Access: 2017-11-17 01:11:20.000000000 -0500 Modify: 2017-11-01 00:45:18.000000000 -0400 Change: 2017-11-26 09:16:15.000000000 -0500  Birth: -   I am unable to see the created time in the output.


Why didn't Voldemort make harder-to-find or indestructible horcruxes?

In the Harry Potter series, Voldemort splits up his soul into 7 pieces and puts the "pieces" in objects that he hides, called horcruxes, so that one would have to "kill" all 7 horcruxes in order to kill Voldemort.  What I don't understand is Voldemort's horcrux choices. Why would he use such obvious things as large pieces of jewellery (Rowena Ravenclaw's diadem), his old diary, or even living, mortal beings like Nagini?   It seems that a safer route would have been to make a horcrux out of a single pebble and throw said pebble on a massive beach or in the ocean; this would have made it impossible for Harry to find it and thus impossible for Voldemort to die.


I was able to successfully create and share the FB Lookback movie, but had to delete it when I saw a picture had been included that should not be shared (someone with their ex).    After deleting the picture I tried to go back to  but it now only gives me a still collage of 6 pictures.  Does anyone know how to get a second chance at the movie?


What's the difference between a microcontroller and a microprocessor?


How to prove that $\lim_{n\to \infty}\sin(n!)$ does not exists?

The continued fraction of $\pi$ has not yet be known.  I could not see the distribution of the $\{\frac{n!}{2\pi}\}$ where $\{x\}=x-\lfloor x \rfloor$.  Is there any idea how to find two convergent subsequences with different limits?


Visa query for flight changes in CDG airport

I hope someone can help me out with some info as I'm getting a lot of conflicting info.  I am landing in Terminal 1 on 3 January with United Airlines from New York and need to take a flight on Air France in Terminal 2E to South Africa. This is not a connecting flight as I have two separate tickets. I will need to collect my baggage from the carousel and then check in for an Air France flight.  I have a South African Passport, my Schengen Visa will have expired on 24 December, but I will have a valid US visa for that trip.  Will I need a visa to be in the airport to collect luggage from one airline and check in at another different airline to fly back home to South Africa?  The embassy says I don't need a Visa if I have a South AFrican Passport and am not leaving the International Zone of the airport. What is considered the "International Zone"?  TIA


How can I deploy a connected app from my sandbox environment to my production environment?

I built a changeset and I was able to include all my classes, but it was a surprise that salesforce has not provided any option to deploy a connected app.  So how do I go about deploying a connected app? Do I need to create it in every other environment?


\documentclass[demo]{article} \usepackage{graphicx} \usepackage{tikz} \begin{document} \begin{tikzpicture} \node[circle,draw,inner sep=2cm]{\includegraphics{myimage.jpg}}; \end{tikzpicture} \end{document}   How do I modify the above code so that the included image is adapted to the circle shape and cropped of the exceeding parts?  I want to specify a shape (a circle) and then include an image respecting the given dimension and cropped.


Entire function with positive real part is constant (no Picard)

A problem asks to show that an entire function on $\mathbb{C}$ with positive real part must be a constant. I spoke to a professor, and asked why not just use the Picard theorem. He said that we should try to aim the solution at the level of the problem, and that Picard was a little too high-powered for this problem.  How would I solve it in the absence of Picard's theorem? A related question: suppose we have an isolated singularity, near which $\Re (f)$ (alternately, $\Im (f)$) is bounded. How can we show the singularity is removable?  Yet another related problem: why is a positive harmonic function on Rn a constant? Mean value property seems not to be the way...


Extra yticks interfering with label distances

I have a series of graphs with similar formatting, but I'm finding some of the labels are positioned too far from the axis numbers, as shown in the screenshots below.     The below code reproduces the problem. If you comment out the extra y ticks line, the issue is corrected, which suggests these are somehow interfering in the calculation used to determine the correct position for the labels.   How can I get the labels to all be placed at the same distance from the axis? It should all look like the image on the right, regardless of whether the extra ticks are present or not.  \documentclass{article} \usepackage{tikz} \usepackage{pgfplots} \begin{document}  \begin{figure}[tp]     \centering     \begin{tikzpicture}     \begin{axis}[     xlabel={Absorption Energy ($cm^{-1}$)},     ylabel={Fluorescence Energy ($cm^{-1}$)},     xtick distance=5,ytick distance=10,minor y tick num=9,     extra y ticks={37425,37435,37445,37455,37465,37475,37485,37495,37505,37515,37525},     extra tick style={major tick length=0.15cm, xticklabels={}, yticklabels={}},     width=12.5cm,height=9.45817cm,     scale only axis=true,font=\footnotesize,enlargelimits=false,axis on top,xtick pos=left,ytick pos=left,tick align=outside,major tick length=0.2cm,tick style={black},scaled ticks=false,/pgf/number format/.cd,  1000 sep={\thinspace},     every axis y label/.style={at={(ticklabel cs:0.5)},rotate=90,anchor=near ticklabel},     every axis x label/.style={at={(ticklabel cs:0.5)},anchor=near ticklabel},     ]      \addplot graphics[xmin=37537.2353, xmax=37566.88252, ymin=37424.51271, ymax=37526.87033, includegraphics={keepaspectratio}] {example-image};      \end{axis}     \end{tikzpicture}     \caption{text} \end{figure}  \end{document}


No Line Break in Author Command? It goes off the page!

by @AndrewSwann demonstrates use of the \author{} command. I am writing an article with a bunch of authors, and when I use this command, it goes off the page:    How can I fix this? Using the same code with more authors:  \documentclass[conference]{IEEEtran}  \begin{document} \title{An Important Conference Contribution}  \author{\IEEEauthorblockN{Author One\IEEEauthorrefmark{1}, Author Two\IEEEauthorrefmark{2}, Author Three\IEEEauthorrefmark{1}, Author Four\IEEEauthorrefmark{2}, Author Five\IEEEauthorrefmark{1}, Author Six\IEEEauthorrefmark{2}, Author Seven\IEEEauthorrefmark{1}, Author Eight\IEEEauthorrefmark{2}, Author Nine\IEEEauthorrefmark{3} and Author Ten\IEEEauthorrefmark{4}} \IEEEauthorblockA{Department of Whatever, Whichever University\\ Wherever\\ Email: \IEEEauthorrefmark{1}author.one@add.on.net, \IEEEauthorrefmark{2}author.two@add.on.net, \IEEEauthorrefmark{3}author.three@add.on.net, \IEEEauthorrefmark{4}author.four@add.on.net}} \maketitle  \end{document}


How to prove that r is a double root if and only if it is a root of a polynomial and of its derivative.

I don't know how to start the question. The title is self explanatory. How to approach and make a formal proof?


Why was she inside a glass room all the time?

In Blade Runner 2049 why Dr. Ana Stelline was inside a glass room all the time?  Why was she not allowed outside, how does she contact with outside world?


Why I have two reference at the same Map object?

In doSomething method I've created a new Map of User objects. Than I've added a new book in the list of books and set the new name for the user. When I call this method the original Map of users users is changed. Why?  Book.java  public class Book {      private String name;      public Book() {     }     //getters and setters }   User.java  public class User {      private String firstName;     private String lastName;     private List<Book> listOfBooks;      public User() {     }      public User(String firstName, String lastName, List<Book> listOfBooks) {         this.firstName = firstName;         this.lastName = lastName;         this.listOfBooks = listOfBooks;     }     //getters and setters }   ListOfBook.java  public class ListOfBook {  private final List<Book> books;  public ListOfBook() {     books = new ArrayList<>();     books.add(new Book("The Lord of the Rings"));     books.add(new Book("The Little Prince")); }  public List<Book> getBooks() {     return books;     } }   ListOfUser.java  public class ListOfUsers {      private static ListOfUsers instance;     private final Map<String, User> users;      ListOfBook books = new ListOfBook();      private ListOfUsers() {         users = new LinkedHashMap<>();         users.put("1", new User("X", "Y", books.getBooks()));         users.put("2", new User("Z", "N", books.getBooks()));     }      public static ListOfUsers getInstance() {         if (instance == null) {             instance = new ListOfUsers();         }         return instance;     }      public Map<String, User> getUsers() {         return users;     } }   Controller.java  public class Controller {      private final Map<String, User> users;      public Controller() {         users = ListOfUsers.getInstance().getUsers();     }      public void doSomething() {         Map<String, User> newUsers = new LinkedHashMap<>();         newUsers.putAll(users);         printUsers(users);         User user = newUsers.get("1");         List<Book> listOfBooks = user.getListOfBooks();         listOfBooks.add(new Book("The Da Vinci Code"));         user.setFirstName("N.N.");     }      public static void printUsers(Map<String, User> users) {         for (Map.Entry<String, User> user : users.entrySet()) {             System.out.print(user.getValue().getFirstName() + " ");         }         System.out.println();     } }   main.java  public class Example {      public static void main(String[] args) {         Controller controller = new Controller();         controller.doSomething();         controller.doSomething();         ListOfUsers listOfUsers = ListOfUsers.getInstance();         Map<String, User> users = listOfUsers.getUsers();         List<Book> listOfBooks = users.get("1").getListOfBooks();         for (int i = 0; i < listOfBooks.size(); i++) {             System.out.println(listOfBooks.get(i).getName());         }         Controller.printUsers(users);     } }


How many particles are there in the entire universe?

How many particles are in the entire (rather than just the observable) universe?  I would guess that if the universe is open, or infinite, then there is a countable infinity of particles. But if the universe is closed, or finite, then there is only a finite number of particles.  Is this correct? Or could a finite universe have a countable infinity of particles or an infinite universe an uncountable infinity of particles.


In there any way to calculate Integral          $$\int_{\frac{1}{2014}}^{2014} \frac{\tan^{-1}x}{x} dx$$      by using simple properties of definite integration. I used substitution $\tan^{-1}x=t $ and applied by parts but then I am stuck at $\int\int \csc(2t)dt$ How should I proceed? What is the most appropriate method to solve this question?


Using Leibniz integral rule when minimizing Expected Absolute Loss

Consider choosing $\theta^*$ that minimizes the expected absolute loss:  \begin{align} \tag{1} \int_{\Theta}|\theta-\theta^*|\pi(\theta|\mathbf{x})d\theta= \int_{-\infty}^{\theta^*}(\theta^*-\theta)\pi( \theta|\mathbf{x})d\theta+\int_{\theta^*}^{\infty}(\theta-\theta^*)\pi(\theta|\mathbf{x})d\theta \end{align}  Differentiating with respect to $\theta^*$ and equating to zero yields: \begin{align} \tag{2} \int_{-\infty}^{\widehat{\theta^*}}\pi(\theta|\mathbf{x})d\theta = \int_{\widehat{\theta^*}}^{\infty}\pi(\theta|\mathbf{x})d\theta \end{align}  EDITED:  I'm confused about the step taken from (1) to (2), which can be found on p. 12 (94) in  (Note: I replaced $\delta(\mathbf{x})$ by $\theta^*$) . A more detailed insight will be highly appreciated. My understanding is that it makes use of Leibniz rule. Here $\widehat{\theta^*}$ is the Bayes estimate (which turns out to be the median of $\pi(\theta|\mathbf{x})$), an argument that minimizes (1).


If sequence $x_n$ converges to $x$, prove that $\sqrt x_n$ converges to $\sqrt x$

If sequence $x_n$ converges to $x$, prove that $\sqrt x_n$ converges to c. I know I have to estimate   $| \sqrt x_n - \sqrt x |$. But I cannot start. Thanks


How to Bind to Static IP address in MySQL

I have an Ubuntu server and I've installed MySQL.  How would I use my two physical static IP addresses in my.cnf bind-address -- can I add two IP addresses?


Good evening, I confess, I'm a begineer. I've just heard about Linux and wanted to try it on my just turned Windows 10 PC.     wubi and Windows 10   Yet, I met a first issue with wubi which told me that the Ubuntu 14.04.3 installer cannot download the metalink and therefore the issue. It also gave me a reference to a log file I don't know how to reach! c:\users\antoine\appdata\local\temp\wubi-14.04-rev286.log I am aware that having windows 10 may prevent me to use wubi. The second issue I met was when I tried to install it manually.   Live CD   After having downloaded ubuntu on a CD, I accessed to the boot interface in order to change the booting. After removing the safe-I-don't-know-what I only had three choices of booting IVP4 IVP6 Windows No Cd booting.   Live key   I also have a liveLinux key a friend of mine gave me to help me instal Linux  My questions are: Is there any chance to boot to my CD in order to really install Linux on my device? Is there any way I can install Ubuntu thanks to the wubi? How can install Linux thanks to this key that doesn't have any .iso file?  Thanks for considering my worries!


how to write a copyable "~" (tilde) in a link of bibliography

I want to have a link on the pdf output of tex file such that when someone copies that and pastes it on a browser (and not by clicking on it), it works. My link has "~", so when I copy it, either nothing is instead of "~" or a wrong character is there. Hence, it doesn't work.  Any idea?


How long will this apple compote keep in the fridge?


In Ubuntu 12.04 -all DVDs were working. After clean upgrade to 14.04 LTS - encrypted DVDs are not working (with VLC and Videos) but non-encrypted DVDs are working. All suggested "Restricted extras", region code were installed - still not working. Any video from Video shop - not playing. Please Help as I'm not an expert (all I can do is highlight and paste to Terminal) ??


How do I clear the purgeable area on my disk?

I cleared space on my disk by deleting files and emptying trash. But, I am unable to make use of the space that I freed up. That is, as you can see the disk reports 142 GB as Available with 83 GB of that as purgeable.    So I should have plenty of space to to copy over a 70 GB file onto the disk. Yet when I try I get an error stating "Not enough disk space to copy", like the following image shows:    How do I clear out the purgeable space to make it truly available for use?  I've tried rebooting in the hopes that a restart clears out the purgeable area, but had no change trying that.


Help center pages for bounties still refer to "Featured" tab

The "Featured" tab on the homepage .  However, the  still refers to it as the "Featured" tab:     The bountied question will appear with a special indicator in all question lists, and it will also be visible on the homepage Featured tab for 7 days.   Also, as Arulkumar commented, the  also refers to it by its old name:     The question gets placed in the home page's featured tab for seven days.   Can these both please be changed to "Bountied" to match the new name of the tab?


how to leave a process running in backgroun on a terminal

I am running some simulation through a server.   I usually login in the server using ssh command from the shell of my laptop.  then I run emacs in terminal mode and with it I start some python simulations.   Now I would like to close the connection between my laptop and the server but leave the simulations and emacs running in the server.   I would like then be able to connect again to the server and restart to work with emacs.   How can I do that?


If a message I starred gets edited, the star state is forgotten

Steps to reproduce   Star any recent message Have the OP to edit it Star count remains, but now it appears as though you haven't starred it (star is black) Star it again for it to receive star state again, but the star count goes down (your original star was removed).


the 'grub-efi-amd64-signed' package failed to install into /target/

I am trying to install Ubuntu 18.04 but I get this error at the end of installation process!  I tried to create a partition with ext4 for \boot. also ext1 but non of them worked. Also I tried to choose the ntfs partition that my Windows 10 grub file is in that but didn't work too.  I also had Ubuntu 16.04 beside my Windows 10 on this Laptop, But when I tried to format the old Linux and install the new one, I get this error message!  (My Windows is installed on sda (Samsung ssd hard))  Edit: Screen shot didn't work and couldn't large the window to show off all the partitions, so I took 2 images:


This is the objective function for Xgboost.  I have no idea where $g_{i}$ and $h_{i}$ came from  is some one explain how this two terms came form?  or direct me to the related tutorial page then I will search for it


If $F$ is a function and $U$ is a set, then what does $F|U$ mean?   In , the Inverse Function Theorem, the notation is used  Also, the file in stating the Lemma 2.14 states that $A \in U$, what does this mean? A set is an element of another set? What is $A$?  EDIT: Could someone kindly explain to me what is going on in Lemma 2.16. How does $\delta$ come into play? I dont see the role in the lemma. I also don't see why this proves one-to-one


way in .NET/C# to easily know if laptop is plugged in?

I'd like to call an API to know if the laptop is plugged into the wall.  If it is I want to defer some CPU intense processing in order to save battery  I'd also like to be informed when this status changes (meaning when the user plugs the charger back in I'd like to be alerted)  in Win32 I'd probally go this route -    is there something like this in .NET/C#?


Why does python2 output differs from python3 when comparing variables(objects?)

Im curious, why does it not equals True in one python version and False in another and vise versa.    big_num_1   = 1000 big_num_2   = 1000 small_num_1 = 1 small_num_2 = 1  print(big_num_1 is big_num_2) # python2 output True; python3 output False print(small_num_1 is small_num_2) # python2 output False; python3 output True   funny thing is my sublime text editor in Python3 does output both as True, where in Terminal it outputs as stated above


Do I need a transit visa or anything to visit the city while on a layover in Amsterdam? if am holding a Schengen visa

I am travelling to Oslo (Norway) from Bahrain with a valid Schengen Visa and I have a stopover of 10 h 30 mins at Amsterdam Airport Schiphol, so will i be able to enter Amsterdam city from the airport?  I had mentioned first port of entry as Oslo (Norway) when I had applied for Schengen visa, so any additional formalities.


Defining starred versions of commands (* macro)

I would like to define a *'d version of a command, something like \newcommand{\foo}{blah} \newcommand{\foo*}{blahblah}  If I try to do this, LaTeX complains that I'm trying to redefine \foo, so I guess I need to do something special to handle *s. But what?


Is C++ addition more error prone compared to multiplication? Can't explain discrepancy

I have noticed a strange problem in C++ where when I add something together by "n" times it does not give the same output as multiplying by "n". Multiplying by "n" gives a better output. Adding by "n" times introduces more error.   For example, with the code below, recalculating length with a for loop of additions (lengthAdditionOutput) introduces greater error than by multiplication (recalculatedLength).      //==================================     DBG("original length: " << length);     //==================================  float distancePerIncrement = length / samplePeriod;  int periodInteger = floor(samplePeriod); float periodRemainder = samplePeriod - periodInteger;  float recalculatedLength = periodInteger * distancePerIncrement + (periodRemainder * distancePerIncrement);      //==================================     DBG("multiplied length: " <<  recalculatedLength << " difference: " << recalculatedLength - length);     //==================================  lengthAdditionOutput = 0.f;  for (int i = 0; i < periodInteger; i++) {     lengthAdditionOutput = lengthAdditionOutput + distancePerIncrement; } lengthAdditionOutput = lengthAdditionOutput + (periodRemainder * distancePerIncrement);      //==================================     DBG("added length: " << lengthAdditionOutput << " difference: " << lengthAdditionOutput - length);     //==================================   The debug output will be for example:  original length: 0.931824  multiplied length: 0.931824 difference: -5.96046e-08 added length: 0.93183 difference: 5.60284e-06   In other words, there is 100 times more error from addition than multiplication, and they are in opposite directions.  I note if I switch the floats to doubles the addition corrects and both methods output the same error (which is unchanged for the multiplication).  Is this normal behavior?   Thanks.


I tried to remove wine from the terminal using :  apt-get remove wine  but wine still exists. How can I remove it completely?  harsh@harsh-BOOK:~$ sudo get-apt purge Q4Wine [sudo] password for harsh:  sudo: get-apt: command not found harsh@harsh-BOOK:~$ sudo get-apt purge wine sudo: get-apt: command not found harsh@harsh-BOOK:~$ sudo rm wine rm: cannot remove ‘wine’: No such file or directory harsh@harsh-BOOK:~$ sudo rm q4wine rm: cannot remove ‘q4wine’: No such file or directory harsh@harsh-BOOK:~$ sudo rm winetricks rm: cannot remove ‘winetricks’: No such file or directory


Method of filling several cells in a grid quickly in Photoshop

I am using Photoshop 7.0 and want to fill a grid with diffent colors   After creating a grid with the pattern-tool (works fine), each cell has to be individually clicked and filled with the filling-tool.   Is there a way to quickly fill several cells with color? instead of clicking each cell? - similar to the "brush" tool? - example below        thanks in advance


Do I need to adjust slow cooker recipes for high altitude?

I live at a high altitude and love to use my slow cooker, but I don't think the meals are coming out as expected when I follow the recipes. Do I need to adjust the recipes for high altitudes?


Should we disallow downvotes for first question if vote total is 0?

In order to be nicer to new participants I think it could be nice if they should not experience a negative vote total for the first question. I think it is one of the most discouraging things to experience if you are just entering the site. When we are new (and not so new) we tend to focus on the number and a negative vote total can make you feel like you have failed. And it is hard to write a Stack Exchange question. So I think the we should be a little less strict to new users on the platform. And I think the quality/integrity of the site is not compromised by having some first question having a zero vote total instead of a negative vote total. So to be clear I want to remove the downvote button for first questions only and only if the voting total is 0 (or less). If others have upvoted you should be able to downvote. What do you think?


How to install a package written by myself?

I have a question. How can I install a package written by myself with MikTeX?  I first made a .txt file than I wrote my package (code) in there. Then I renamed the .txt file to .sty . What should I do now?  Thank you for your answeres.


Both numbers are above $8,$ their HCF is $8$ and their LCM is $80.$ Find the two possible numbers. I'm very stuck on this question and was wondering if there was an easy way to answer it


Given a set and an element, can we say that the element is subset of the given set?

Let us consider a set $A = \{1, 2, 3, 4, 5\}$ and an element say $1$.  Can we say that  $1$ is subset of set $A$.  If not, please explain.


Function $f\in M[G]$, $f:\kappa\to M$ is in the ground model implies $\kappa^+$-Baire

Let $M$ be countable transitive model of ZFC, $P\in M$ be poset and $\kappa$ be a cardinal in $M$. In addition, for every $P$-generic filter $G$ over $M$, if a function from $\kappa$ to $M$ is in $M[G]$ then the function is in $M$. My problem is: $P$ satisfies $\kappa^+$-Baire property in $M$? A poset $P$ satisfies $\alpha$-Baire property if for each $\alpha<\kappa$, the intersection of $\alpha$ many collection of open dense subsets $\{D_\xi:\xi<\alpha\}$ is dense. Also, a subset $D\subset P$  is open dense if $D$ is dense and $D$ is lower set (i.e. $x\in P$ and $y\le x$ then $y\in P$.) I saw a hint of the problem from Jech, exercises 15.5. However the hint is about Boolean-valued model and I am not familiar with Boolean-valued model. I want to get a proof of above problem not mentioning about Boolean-valued model but I don't know how to start it from Jech's hint. Thanks for any help.   (Jech 15.5) . If every $f : κ → V$ in $V^B$ is in the ground model, then $B$ is $κ$-distributive. [Let $W_α$, $α<κ$, be partitions of $B$. Consider $\dot f ∈ V^B$ such that  $\|\dot f(α) = u \|= u$ for $u ∈ W_α$, and find a common refinement of the $W_α$.]


Are there any differences between PIR, oblivious transfer and differential privacy?

I am trying to make a taxonomy of the different purposes of some cryptographic protocols. Generally speaking, the purpose of PIR, oblivious transfer and differential privacy--it sounds as if they were invented for the same purpose: "Give me the information I want without learning anything about this information".   Can we make the aforementioned generalization?


ubuntu 20.04 cannot switch between two windows of the same app neither using mouse nor super+tab

Gnome 3.36.3 Seems like windows are grouped and moving active one of them second one also moves, I cannot switch to not active one till active is closed ... strange behaviour which I cannot google ... could someone point me to solution?


Entire $f$ and $g$ constant if $e^{f(z)}+e^{g(z)}=1$

Suppose we have entire functions $f$ and $g$ that satisfy $e^{f(z)} + e^{g(z)} = 1 $ for all complex values $z$.  Show that $f$ and $g$ are constant.


What is the duality relationship between eigensystems of X X' vs X' X?

I want to know the relationship between the eigensystems of two non-negative-definite (covariance-like) matrices.  Both are derived from X which is a T-by-K real matrix (wlog say K > T).  I avoid subtracting the mean to avoid complicating the main issue which is about the eigensystem structure.  Ct = (1/T) * X' X = Et Lt Et' Ck = (1/K) * X X' = Ek Lk Ek'  .... where Et, Lt are the (column) eigenvectors and diagonal matrix of eigenvalues respectively for Ct, and Ek Lk are the same for Ck.  I remember vaguely from school that there is some kind of duality relationship here (between the two eigensystems) which is particularly interesting because both matrices have rank T < K, and hence only T of the diagonal elements of Lt are nonzero.  Does anyone know this relationship explicitly? Thanks in advance for any light you can shed!


Why does running a game engine script from the text editor cause an error?

Why does running you Python script using "run script" option in text editor generate an error called "bge module not found", while executing it using P command doesn't cause any problems?


If all entries of an invertible matrix $A$ are rational, then all the entries of $A^{-1}$ are also rational. Now suppose that all entries of an invertible matrix $A$ are integers. Then it's not necessary that all the entries of $A^{-1}$ are integers. My question is:  What are all the invertible integer matrices such that their inverses are also integer matrices?


I am having a tough time understanding the difference between both terms. Could someone please clear up what both terms mean and in the process of doing so, explain the difference between them?


how to remove ubuntu 12.04 from dual booting with windows xp with xp installation cd

I have dual booting system with Ubuntu 12.04 and Windows XP. Now I want to remove Ubuntu 12.04 and retained Windows XP.  How do I remove the Ubuntu 12.04 with Windows XP installation CD command prompt?


Trying to find the $\delta$ in epsilon-delta continuity proof.

I am trying to prove the following function is continuous for all irrationals: $f(x) = \begin{cases} 0,  & \text{if $x$ is irrational} \\ 1/n, & \text{if $x = m/n$} \end{cases}$ The question assumes $m/n$ is in lowest terms. I have shown that it is discontinuous for all rationals, and now I believe I have to either use the $\epsilon-\delta$ definition of continuity or sequential continuity to show the function is continuous for when $x$ is irrational. I split my attempt into two cases: Our value of $x$ is irrational, then I want: $$\forall \epsilon > 0, \exists \delta > 0, |x-a|<\delta \implies |f(x) - f(a)| < \epsilon$$ $a$ is irrational here. Using that $x$ is irrational I get that $f(x) = 0$ as does $f(a)$ so no matter the $\delta$ we have our condition for continuity  satisfied as $0 < \epsilon$ for all $\delta$ Our value of $x$ is rational i.e. $x = \frac{m}{n}$ subbing in we want: $$\forall \epsilon > 0, \exists \delta > 0, |\frac{m}{n}-a|<\delta \implies |\frac{1}{n}| < \epsilon$$ I am struggling to find the $\delta$ necessary. I am able to bound $|\frac{m}{n}-a|$ by $1+2|a|$ if I say that $\delta \le 1$. However I do not know how to find a $\delta$ to yield the second inequality. Should I change my approach to sequential continuity?


Proof that for infinite sets, bijections and injections are equivalent

Online I found the following statement that for $X$ an infinite set, if there is a bijection from $X$ to $\mathbb{N}$ this is equivalent to there is an injection from $X$ to $\mathbb{N}$. How would I prove this?  Attempt: The fact that if there is a bijection it is also an injection is true by definition of bijection. Beyond that, I don't know how to demonstrate that an injection is equivalent to a bijection for an infinite set $X$ to $\mathbb{N}$.


Prove that $F_{n}^{2}+F_{n+1}^{2}=F_{2n+1}$   This identity holds for $n>=1$  Instead of using induction, how do I prove it in a geometry approach?


How does Windows page when there are multiple pagefiles on multiple disks?

Let's say I have two internal HDDs and configure Windows to place pagefiles on both of them. How do pagefile writes occur?  Are pagefile writes spread evenly across the disks?  Does Windows prefer accessing the higher-performing disk (perhaps measured through pagefile I/Os)?  Does Windows access them sequentially, starting on disk #1, and only proceeding to the pagefile on the second disk when the first is full?  Why I ask: If there are two disks with greatly different performance characteristics (a 5.4K HDD and 15K HDD, for example), it could potentially be a detriment to place a pagefile on both disks if the one on the higher-performing disk will never be accessed.


Get type that implements generic interface by searching for a specific generic interface parameter

I'd like to create a method that returns a type (or IEnumerable of types) that implement a specific interface that takes a type parameter -- however I want to search by that generic type parameter itself.  This is easier demonstrated as an example:  Method signature that I want:   public IEnumerable<Type> GetByInterfaceAndGeneric(Type interfaceWithParam, Type specificTypeParameter)   And then if I have the below objects    public interface IRepository<T> { };   public class FooRepo : IRepository<Foo> { };   public class DifferentFooRepo : IRepository<Foo> {};   I then want to be able to do:    var repos = GetByInterfaceAndGeneric(typeof(IRepository<>), typeof(Foo));   and get an IEnumerable containing the types FooRepo and DifferentFooRepo.  This is very similar to , however using that example I would like to search by both IRepository<> and by User.