C: Undefined reference to 'xxx' function

I am facing undefined reference issue while creating executable.  Error:  ../build/kl/Release/test/maker/guibase.o: In function `decodeAddrList': tree234.c:(.text+0xc): undefined reference to `ptritclStubsPtr' tree234.c:(.text+0x20): undefined reference to `ptritclStubsPtr' tree234.c:(.text+0x12c): undefined reference to `ptritclStubsPtr' tree234.c:(.text+0x140): undefined reference to `ptritclStubsPtr'   Build Command:-  pkgs/gcc/v4.8.3/bin/gcc -L/usr/X11R6/lib -O2 -DUSE_FLEX -Wall -Wno-char-subscripts -fPIC -DLINUX -DG_DISABLE_CONST_RETURNS -fno-strict-aliasing -o ../build/kl/Release/test/bin/pure.exe -L../build/kl/Release/test/modules ../build/kl/Release/test/maker/constrfunc.TCL.o ../../build/kl/Release/test/maker/pvdbprocs.TCL.o .. ../build/kl/Release/test/maker/maker/memmaker.TCL.o .. ../build/kl/Release/test/maker/modules/libdenbase.a .. ../build/kl/Release/test/maker/guibase.o  -lcdnviptcl8.4 -ldenbase -lglib-2.0 -ldenbase -lX11 -ldl -lm -lviputil -lvippli -lcdsCommonMT_sh -lpthread  -L/home/dlb/extlibs/arm/lib    I have that symbol defined in the library 'libcdnviptcl8.4' at path '/home/dlb/extlibs/arm/lib' . But still facing the same issue.  Symbol :-  readelf -s libcdnviptcl8.4.so | grep ptritclStubsPtr   636: 00000000000d8068     8 OBJECT  GLOBAL DEFAULT   24 itclStubsPtr 1240: 00000000000d8068     8 OBJECT  GLOBAL DEFAULT   24 ptritclStubsPtr   Am I missing some thing here? Please help  Quote from comment by OP: "Due to some privacy issues...I am renaming the symbols.. It was edited by me... It was typo...I just corrected it...:)" I.e. the identifiers in the error message and the grep line and the output of the grep line have been manually altered.


I want to center verticaly a paragraph in a div. For that, I tried to add an image front my text and I add the css "vertical-align:middle" on it.  The first line of my text is verticaly aligned : it's good, but the second line is under my div.  How can I solve my problem ?  Thks    div {     height:200px;     width:200px;     text-align:center;     background:cyan;     position:absolute; }  span {     height:inherit;     width:inherit;     position:absolute;     left:0;     background: yellow;     text-align:center  }  img {     height:100%;     vertical-align:middle;     width:3px;} }


Remove duplicate $PATH entries with awk command

I am trying to write a bash shell function that will allow me to remove duplicate copies of directories from my PATH environment variable.   I was told that it is possible to achieve this with a one line command using the awk command, but I cannot figure out how to do it. Anybody know how?


Image segmentation network to extract questions from an image of a test paper?

This is the sample document ->  I want to extract questions along with the options. There are other question papers as which have questions with diagrams in them. I want to be able to extract them as well. End goal is to store them in a question bank. I am planning to run an image segmentation algorithm to extract the questions along with their options. Will that be feasible? Suggestions are more than welcome.


Infinite collection of infinite sets whose union converges to a defined set?

I was driving around and thinking about the sets that we commonly use in mathematical proofs such as $\mathbb{Z}$ or $\mathbb{Q}$. In many introductory proofs courses, these sets seem to be the building blocks of many definitions (such as what makes a number even or odd) or lemmas. In addition to having their own symbols, this sometimes gives off a perception to many introductory proofs students that these sets, while having infinite elements, are somehow singular and entities$^*$.  $^*$(I'm aware that some of these common sets are subsets of the others and aren't "singular" per se. I was trying to convey a description of their perception among students, including myself, due to their prevalent use which spurred this question to begin with).   It got me thinking, can you take a "reductionist" approach and fragment these common sets into an infinite mutually exclusive infinite sets of which the totality of their elements converges to these "special sets"? For example, to start simple, I was wondering if it was possible to have an infinite collection of infinite sets $n_1, n_2, n_3....n_j, n_{j+1}....$ such that:   $n_a\cap n_b=\emptyset$ for $a\neq b$, $\forall$ $a$ and $b$ that are indices to describe the infinite set. $\bigcup^\infty_{i=1} n_i = \mathbb{N}$


If the line $y=x-8$ intersects the parabola ${ y }^{ 2 }=4x$ at A and B, what's the chord's length?

How to find the coordinates of the points A and B? If one gets that, then distance formula can be used to find the length.


Who was the first DC/Marvel costumed crime fighter credited as being a former Olympic athlete?

Some of the DC/Marvel costumed crime fighters biographies show them to be former Olympic athletes. Who was first of them with that credential?


How to formally prove the negation of a statement "A if and only if B"?

Motivated by ,  I'm trying to establish a logical proof to the fact that the following statement is false:     $2x+1$ is prime if and only if $x$ is prime.    There are several ways to prove it of course, but I'm trying to understand where have I gone wrong with the following logical proof, so any help pointing out the error would be highly appreciated.    Let $\mathbb{P}$ denote the set of prime numbers.  We need to prove the logical statement:  $\neg({2x+1}\in\mathbb{P}\iff{x}\in\mathbb{P})$  Or the equivalent logical statement:  $\neg[({2x+1}\in\mathbb{P}\implies{x}\in\mathbb{P})\wedge({x}\in\mathbb{P}\implies{2x+1}\in\mathbb{P})]$  Or the equivalent logical statement:  $\neg({2x+1}\in\mathbb{P}\implies{x}\in\mathbb{P})\vee\neg({x}\in\mathbb{P}\implies{2x+1}\in\mathbb{P})$  Or the equivalent logical statement:  $\neg[({2x+1}\not\in\mathbb{P})\vee({x}\in\mathbb{P})]\vee\neg[({x}\not\in\mathbb{P})\vee({2x+1}\in\mathbb{P})]$  Or the equivalent logical statement:  $[({2x+1}\in\mathbb{P})\wedge({x}\not\in\mathbb{P})]\vee[({x}\in\mathbb{P})\wedge({2x+1}\not\in\mathbb{P})]$    That last statement is obviously false, for example, with $x=2$.  But this very example yields false statements "all the way up that proof".  So I'm thinking that my initial interpretation of $\neg({A}\iff{B})$ is incorrect somehow.


How should I go about doing regression with a series of exponents involved?

I have a table of data with input values and target values, and I was tasked to do something quite peculiar. I was tasked to run a sort of exponential regression and report back with the coefficients and the series of exponents. Let me explain:  Vanilla Linear Regression will minimize sum of squared error to create a linear combination in the format of $[a_1x_1 + a_2x_2...]$ where $a_i$ represents the series of coefficients and $x_i$ represents the different input features. This means that solving for the coefficients on linear regression is fairly easy given enough linearly independent data points.  I was given a dataset, and I was tasked to create an equation in the form of $[a_1x_1^{n_1} + a_2x_2^{n_2}...]$ where $a_i$ is the coefficients, $x_i$ is the input features, and $n_i$ signifies an exponential value.   I believe that since $a_i$ and $n_i$ need to be solved for, there are too many variables involved to go about this problem in a simple manner.   Is something like this even something like this even solvable? If so, how would you go about it statistically, and how would you go about it in python?  p.s. The task also says that all exponents, $n_i$, need to be between 0 and 1, so that might make it a bit easier.  p.s.s. I know that $[a_1x_1^{n_1} + a_2x_2^{n_2}...]$  is not linear unless all $n_i$ variables are either 0 or 1 but I wrote "linear regression" in the title because the two general formulas are similar.


I run Ubuntu 14.04. Using the terminal, I did netstat -taupen to see what processes are running and I got this result:  Local Address        Foreign Address     State        User   Inode    PID/Program Name 192.168.1.3:54179    23.62.236.99:80     TIME_WAIT    0      0        -   Why is this ip connected to one of my ports? Also, ShieldsUp says port 54179 is stealthed, so what is going on?


Copying rows error message "Operand should contain 1 column(s)"

I am trying to transfer data from one row to another within phpmyadmin, but when I attempt i I get the following error message.  Operand should contain 1 column(s)   Code I attempt :  INSERT INTO users_links      (`username`,`facebook`)     SELECT      (`username`,`facebook`)     FROM users2   However when I try this it works but Its not what I want.  INSERT INTO users_links          `username`         SELECT          `username`         FROM users2   Any ideas?


Let $A$ be an $n\times n$ real matrix which is nilpotent. Prove that if for the entries of the matrix: $a_{ij}=-a_{ji}$ then $A$ has to be $0$.  I know that this is equivalent to saying that $A^T=-A$ but I don't see how to prove $A=0$ yet. Does anyone have an idea? Thanks a lot!


I have a span tag as follows:  <span>&times;</span>  In JavaScript, if I check   $("span").html()  Response is: "-"  Is there any way I can compare   $("span").html() == "&times;"   instead of $("span").html() == "-"?


How to handle swear words in quote / transcription?

In my research, I interview practitioners/real users. One of them, a native english speaker, used a lot a swear words (basically the f-word).  Question: how to deal with curse words in content you need to quote?  Since I use transcripts for a content (and not formal) analysis, I sometime 'smooth' interviewee wordings (like removing "hum", "well", "you know", and other recurring verbal tics). In some case, I could remove the f-word:     it's just super f*cking slow, and really f *cking annoying   However, in some cases it is less harmless, because it more deeply changes the perceived meaning:     if you don't want to do things, just don't f*cking do it      oh f *ck, we'll just go back to do, as we were doing   and in some other, I simply cannot change interviewee's words:     [...] he really tried and wanted to build up, but he completely f*cked up every single part of every single thing.     Since I am not a native speaker, I don't know how "bad" would using the f-word be perceived (which is why I tried to be careful here.)  In some cases, I could do a cut quote, e.g. "it's just super [...] slow, and really [...] annoying", but it looks like I'm not accurately depicting the wordings.  I've also seen on the internet people using 'f*ck' standing for the f-word. Could this be a solution? (I personally find this solution a bit prudish.)  Otherwise, could I simply quote them? Should I put a warning somewhere?


How did Dumbledore's drinking of the poison help to get a horcrux?

Why did Dumbledore drink the potion? How did that help to find the horcrux?


I have a simple example
add more text
   When you click on this text      jQuery('#test').on('click', function (event) {         $('body').append("
new test
");     });   you get some more text appear. After I have clicked on 'add more text' my page looks like this
add more text

new test
   I am wondering what I need to do to interact with the newtest div?  If I put the below in.  jQuery('#newtest').on('click', function (event) {     alert('not working?'); });   Nothing happens. How do I interact with content that gets added after load? I thought .on helped me do this?


Statistically, is there a safest seat on the plane if it crashes?

So to clarify, there are lots of different planes, so for the sake of argument, there are areas:   front left front right front middle forward front, right, middle over the left wing over the right wing middle, between the wings mid-way back, left, right, or middle at the back left, right, or middle pilot seat co-pilot seat jump-seat, if it exists   So that's 18ish possible safe zones in the plane.  Is there a particular area that statistically people have survived more (or less) in?


I am reading a the proof of a theorem that says that $3$-perfect codes can only have length $7$ or $23$. I do not understand the following:  It follows from the definition that if $n$ is the length of a $3$-perfect then we must have that $(n+1)((n+1)^3-3(n+1)+8) = 3 \cdot 2^k$ for some $k \in \mathbb{Z}^+$. Now the proof claims that $16$ can not divide $(n+1)$.  I do not why. Any help or hints appreciated.


When I was a kid, I was always taught to refer to years using BC (Before Christ) and AD (Anno Domini / year of our Lord).  However, I somewhat regularly hear people referring to years as in the CE (Common Era) or BCE (Before the Common Era).  Why do people use the latter terminology?  For one thing, I find it confusing.  It doesn't help that BCE is similar to BC.  But moreover, there is only one letter of difference between the two terms, whereas with BC and AD, the terms are clearly different and I find it easier to distinguish!  Were BCE/CE established earlier than BC/AD?


How can one prove that $\pi^4 + \pi^5 < e^6$?

A proof of the inequality using properties of $\pi$ and $e$, for example, is what I'm looking for. Not calculator approximations showing the inequality holds.


Should I self-fund my PhD at one of the top 10 universities at UK?

I will start my PhD in the field of Biomedical Computer Vision soon at one of the top 10 universities at UK. I am an international student from Asia.  But unfortunately I haven't received any source of funding yet (no university scholarship, no supervisor grant) to cover my PhD. The tuition fees alone per year is only slightly less than 20,000 British Pounds, which is something I cannot afford on my own for all my years of PhD.   I am thinking of going there initially for one year with self-funding, by taking money from my savings and some from my parents, and will risk it initially and try to secure a source of funding there after starting my PhD, and if everything goes well will have figured a way to fund myself from some grant or scholarship.   I have been thinking about this since many many days now and am not able to make a decision about whether I should go there or not. And if things go really bad financially, what would be ways out ?  Any comments or help is much needed and highly appreciated.


If $x=2\pi/2009$, then evaluate $\cos x \cos 2x \cos 3x \cdots \cos 1004x$

I have been recently trying to solve a continued product of cosines:     If $x=2\pi/2009$, then evaluate   $$\cos x \cos 2x \cos 3x \cdots \cos 1004x$$   I have found formula for this which says product of this series is $\pm(1/2^n)$.   I'm recently in 11th, so please try to give this proof according to my knowledge


I'm using CM 10.2 nightlies on my S 3 (i9305, intl. w/ LTE).  However, even though I seem to be connected to a network - the status icon is greyed out.  What's even weirder: I can access the web, but not the Play Store, which just displays 'No connection' and 'try again'.  See:    but:    Notice the grey WiFi icon in the top right corner - it used to be blue!  How can I diagnose/fix this issue?


what can I say instead of "out of school" here?

I want to say that "now, I'm studying things other than what I learn in school" with this present perfect sentence: Due to quarentine, I have begun to study things out of school, especially languages. Is out of school idiomatic in this context? What could sound better? Thank you


Let $F : X → X$ be continuous. Prove that the set $\{x ∈ X : F(x) = x\}$ of fixed points of F is closed in X

Here X is a Hausdorff Space.  I know that singleton sets, {x}, are closed in a Hausdorff space. Although Im not sure if thats how to use the Hausdorff property.   Should I investigate $h=F(x)-x$?  Can anyone give a hint


Cannot read property 'setParams' of undefined when trying to implement lightning custom Action

I am trying to implement custom action in lightning . The below controller code is to add two numbers and display using toast. It is however throwing the error :     Action failed: c:CustomAction$controller$clickAdd [Cannot read   property 'setParams' of undefined]   The js controller code is:  ({ clickAdd: function(component, event, helper) {     // Get the values from the form     var n1 = component.find("num1").get("v.value");     var n2 = component.find("num2").get("v.value");     // Display the total in a "toast" status message     var resultsToast = $A.get("e.force:showToast");     resultsToast.setParams({         "title": "Quick Add: " + n1 + " + " + n2,         "message": "The total is: " + (n1 + n2) + "."     });       resultsToast.fire();         // Close the action panel var dismissActionPanel = $A.get("e.force:closeQuickAction");         dismissActionPanel.fire();     } })   The component code is :      <!--quickAdd.cmp--> <aura:component implements="force:lightningQuickAction">     <!-- Very simple addition --> <lightning:input type="number" name="myNumber" aura:id="num1" label="Number 1"/> +     <lightning:input type="number" name="myNumber" aura:id="num2" label="Number 2"/>     <br/>     <lightning:button label="Add" onclick="{!c.clickAdd}"/> </aura:component>   I have copied this piece of code directly from the standard lightning guide.


How to find the eigenvalues of the following tridiagonal matrix

The $n$-order tridiagonal matrix is defined by $A(i,i)=0, A(i,i+1)=n-i, A(i+1,i)=i$, i.e., $$A=\begin{pmatrix}0&n-1\\1&0&n-2\\&2&0&n-3\\&&\ddots&\ddots&\ddots\\&&&n-2&0&1\\&&&&n-1&0\end{pmatrix}$$ All eigenvalues of $A$ are $-(n-1),-(n-3),\ldots,(n-3),(n-1)$, however, I could not figure out a simple way to show that.


How to get the IMEI number of a lost phone?

I lost my Android phone Vivo 1713 (v5s) recently. I don't know its IMEI number. How do I get it?


What are major differences between C# and Java?

I just want to clarify one thing. This is not a question on which one is better, that part I leave to someone else to discuss. I don't care about it. I've been asked this question on my job interview and I thought it might be useful to learn a bit more.  These are the ones I could come up with:   Java is "platform independent". Well nowadays you could say there is the  project so C# could be considered too but I believe it is a bit exaggerating. Why? Well, when a new release of Java is done it is simultaneously available on all platforms it supports, on the other hand how many features of C# 3.0 are still missing in the Mono implementation? Or is it really  vs.  that we should compare here? Java doesn't support events and delegates. As far as I know. In Java all methods are virtual Development tools: I believe there isn't such a tool yet as Visual Studio. Especially if you've worked with team editions you'll know what I mean.   Please add others you think are relevant.  Update: Just popped up my mind, Java doesn't have something like custom attributes on classes, methods etc. Or does it?


Is it good to start a sentence with 'And'?

In my impression, this is very very common in the bible.   But how about scientific writing?


I am reading an example off a grammar book.   Snow white smiled at the dwarves and me/I.   "Me" or "I" should I choose and in which situation should I use me or I?


I have recently come across a land vehicle called Blackbird, the inventor of which claims that it can run directly downwind faster than wind. It is sponsored by Google and there were some tests which showed that the vehicle can run up to 2.8 times the windspeed.  I find it really interesting so I did some search about the topic on the internet. After reading several articles and forum threads related to the topic, I am still confused about how it exactly works.  To begin with, the explanation of the team that built the vehicle can be summed up as follows: wind pushes the frame of the car, which makes the wheels roll, the wheels then rotate the propeller, the propeller extract wind power to produce thrust that drives the car forward. How can a propeller do such thing? How can it use power out of the wind to create thrust in a direction opposite to the wind?  Secondly, I have also looked at some formulas that are claimed to be the description of how the vehicle works. One formula (from a professor named Mark Drela) shows zero propeller power when the vehicle speed equals wind speed, so apparently the vehicle could not exceed wind speed, but it could still accelerates given it is already at a speed greater than wind speed. How could it reach 2.8 times the wind speed in the test?  This confusion also led me to doubt the actual test itself, so I searched further and found a thread on international skeptics forum, in which there are some who critized the way the data was measured and processed. In particular, the measurement data was processed by the inventors, not by a third party, which raises doubts about transparency, the placement of measurement instrument and data processing after the test could also hide gust and change in wind direction (making it not directly downwind). Why couldn't they just test in a wind tunnel?  Could someone explain whether this works. If so, what is wrong in my understanding of the way it works?


failed (111: Connection refused) while connecting to upstream python

I am experiencing 502 Bad Gateway errors after deploying a python flask application using dokku on digital ocean. I followed  to deploy my app on digital ocean using dokku.  2018/10/23 07:40:59 [error] 28652#28652: *1 connect() failed (111: Connection refused) while connecting to upstream, client: xxx.xxx.xxx.xx, server: api.domain.com, request: "GET / HTTP/1.1", upstream: "http://172.17.0.3:5000/", host: "api.domain.com"   Here is proof that the app is up and listening for requests:  2018-10-23T07:37:30.165794640Z app[web.1]: [2018-10-23 07:37:30 +0000] [9] [INFO] Listening at: http://127.0.0.1:8000 (9)   My question is how configure proxy_pass in a python flask dokku application.


Why do users often ask blatantly off-topic questions here on Meta?

For quite some time, newer users seem to ask a lot of blatantly off-topic questions here on Meta. They are mostly programming questions that should have been closed asked on Stack Overflow, along with some other questions that would fit into Super User or Server Fault, as well as a few others that have totally nothing to do with the Stack Exchange network. I'm curious as this issue seems to be specific to Meta Stack Exchange (and MSO to some extent), and the frequency varies every day. What could be the cause?


event listener does not work after append

Recently I started to learn HTML/CSS and jQuery so I was trying to make a little web game. here is the code of HTML:    function playGame() {         var theLine = "
";          for (var i = 0; i < 9; i++) {             theLine = theLine + "<button class=\"ticButton\"> chose </button>";         }          theLine = theLine + "
";         var instr = "
 choose wisely
";          $("body").append(instr);         $("body").append(theLine);     }      $(document).ready(function () {         $("#game").click(function () {             alert("be aware");             $("#game").hide();             playGame();         });          $(".ticButton").click(function () {             alert("you won");         });     });  <!DOCTYPE html>             <title> Play </title>      <link href="style.css" rel = "stylesheet" type="text/CSS" />
 Welcome
  <button id="game"> play </button>                 so my purpose is, after clicking the play (id = game) button, there should appear 9 new buttons and after clicking any of them the alert should be raised saying: you won. But what happens is: after 9 new buttons appear, nothing happens when you click them. Any suggestions? I want to mention that there is a question about event listeners, which doesn't work after dynamic creating but that question and its answers was not helpful for me.


Is looking at an eclipse worse than looking at the sun?

I understand why looking at the sun is bad.  I also understand that looking at the eclipse is bad.  Is it more dangerous to glance at an eclipse than the sun, assuming you avert your eyes right very quickly?  I assume that the dangers of looking at an eclipse is that there is less light coming off the eclipse, but that the energy is similar meaning physically my eyes wont shut/pupils won't react the same?  Can someone help me with the science that makes eclipses so much more dangerous to look at then the sun, if this is the case?


Can there be an injective function whose derivative is equivalent to its inverse function?

Let's say $f:D\to R$ is an injective function on some domain where it is also differentiable. For a real function, i.e. $D\subset\mathbb R, R\subset\mathbb R$, is it possible that $f'(x)\equiv f^{-1}(x)$?  Intuitively speaking, I suspect that this is not possible, but I can't provide a reasonable proof since I know very little nothing about functional analysis. Can anyone provide a (counter)example or prove that such function does not exist?


I recently installed Lubuntu 16.04 on my laptop & I can't seem to get it to connect to WiFi. I tried using the Network Manager but it won't even start. At first I thought it wasn't installed so I tried:  sudo apt-get install network-manager-gnome   The output tells me it's already installed & up to date with the most recent version. I also tried adding "nm-applet" to the Default applications for LXSession on the Autostart tab & rebooting the laptop, but even after that it just doesn't appear on the panel or start with a command from the terminal. I tried:  sudo nm-applet   To start it, but the output was:  ** (nm-applet:20844): WARNING **: Error retrieving accessibility bus address: org.freedesktop.DBus.Error.ServiceUnknown: The name org.a11y.Bus was not provided by any .service files  (nm-applet:20844): Gdk-CRITICAL **: gdk_window_thaw_toplevel_updates: assertion 'window->update_and_descendants_freeze_count > 0' failed   The output of:  lspci -knn | grep Net -A2   was:  03:00.0 Network controller [0280]: Broadcom Corporation BCM4312 802.11b/g LP-PHY [14e4:4315] (rev 01)     Subsystem: Dell Wireless 1397 WLAN Mini-Card [1028:000c]     Kernel driver in use: b43-pci-bridge


Whenever I try and draw in Adobe Illustrator the lines always do this weird thing where they sort of fill in a bit...  How do I stop this? As it is really annoying while trying to draw... Thank you


Can someone explain the Navier Stokes equations?

I am doing a research work on the Navier stokes equations but I don't really understand them, as I am a high school student. Could someone explain them to me in an easy way but kind of specific? Thank you


Ubuntu 18.04 on x86 wants to load arm64 repositories

As a developer I might have broken something as my 18.04 tries to load packages also(?) for arm64:  $ sudo apt update Ign:1 http://dl.google.com/linux/chrome/deb stable InRelease Hit:2 http://packages.microsoft.com/repos/vscode stable InRelease               Hit:3 http://ppa.launchpad.net/maarten-baert/simplescreenrecorder/ubuntu bionic InRelease Hit:5 http://dl.google.com/linux/chrome/deb stable Release                  Get:4 http://archive.ubuntu.com/ubuntu bionic InRelease [242 kB] Get:6 http://archive.ubuntu.com/ubuntu bionic-updates InRelease [88,7 kB] Get:7 http://archive.ubuntu.com/ubuntu bionic-backports InRelease [74,6 kB] Get:8 http://archive.ubuntu.com/ubuntu bionic-security InRelease [88,7 kB]  ...  Fetched 494 kB in 2s (249 kB/s)                   Reading package lists... Done  E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/bionic/main/binary-arm64/Packages  404  Not Found [IP: 91.189.88.162 80]  E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/bionic-updates/main/binary-arm64/Packages  404  Not Found [IP: 91.189.88.162 80]  E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/bionic-backports/main/binary-arm64/Packages  404  Not Found [IP: 91.189.88.162 80]  E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/bionic-security/main/binary-arm64/Packages  404  Not Found [IP: 91.189.88.162 80]  E: Some index files failed to download. They have been ignored, or old ones used instead.   Why is this happening? Where does it get that binary-arm64?  There are no *.list under my /etc/apt/ that would include anything related to arm.


Is the set $\{\big(x,\sin(1/x)\big):x\ne 0 \}$ connected in usual metric of $\mathbb R^2$?

Is the set $\{\big(x,\sin(1/x)\big):x\ne 0 \}$ connected in usual metric of $\mathbb R^2$ ?   I tried writing it as a union of two connected sets , or otherwise as a union of two disjoint non-empty open sets without any success , Please help . Thanks in advance


Understanding d-separation theory in causal Bayesian networks

I am trying to understand the d-Separation logic in Causal Bayesian Networks. I know how the algorithm works, but I don't exactly understand why the "flow of information" works as stated in the algorithm.    For example in the graph above, lets think that we are only given X and no other variable has been observed. Then according to the rules of d-separation, the information flow from X to D:   X influences A, which is $P(A)\neq P(A|X)$. This is OK, since A causes X and if we know about the effect X, this affects our belief about the cause A. Information flows. X influences B,which is $P(B)\neq P(B|X)$. This is OK, since A has been changed by our knowledge about X, the change at A can influence our beliefs about its cause, B, as well. X influences C,which is $P(C)\neq P(C|X)$. This is OK because we know that B is biased by our knowledge about its indirect effect, X, and since B is biased by X, this will influence B's all direct and indirect effects. C is a direct effect of B and it is influenced by our knowledge about X.   Well, up to this point, everything is OK for me since the flow of the information occurs according to intuitive cause-effect relationships. But I don't get the special behavior of so called "V-structures" or "Colliders" in this scheme. According to the d-Separation theory, B and D are the common causes of C in the graph above and it says that if we did not observe C or any of its descendants, the flow information from X is blocked at C. Well, OK, but my question is why?  From the three steps above, started from X, we saw that C is influenced by our knowledge about X and the information flow occurred according to the cause-effect relationship. The d-Separation theory says that we cannot go from C to D since C is not observed. But I think that since we know that C is biased and D is a cause of C, D should be affected as well while the theory says the opposite. I am clearly missing something in my thinking pattern but can't see what it is.  So I need an explanation of why the flow of information blocked at C, if C is not observed.


Sufficient conditions for $\lim_{m \to \infty}\lim_{n \to \infty} a_{mn} = \lim_{m \to \infty}\lim_{n \to \infty} a_{mn}$

Recently I came across with some problems concerning the following fundamental problem in the advanced calculus: $$\lim_{m \to \infty}\lim_{n \to \infty} a_{mn} = \lim_{m \to \infty}\lim_{n \to \infty} a_{mn}$$  Is there any sufficient(or necessary and sufficient, if there is) conditions for this limit equality? I know from the Fubini's theorem that $\sum^{\infty}_{m=1}\sum^{\infty}_{n=1}a_{mn}=\sum^{\infty}_{n=1}\sum^{\infty}_{m=1}a_{mn}$ under some conditions for $a_{mn}$


I created a partiton on my hard drive (160GB) and then made used Universal USB Installer to make it bootable for Ubuntu 16.04. So I restarted my PC and displayed ubuntu install options. Then I clicked on install ubuntu and gives the error End Kernel panic -not syncing: VFS: Unable to mount root fs on unknown-block(2,0). I also tried to boot from first hard drive but it also failed. So I'm stuck at the ubuntu install options.  How can I resolve this?


i forgot password  to use sudo and password for logging as root from login prompt  I forgot My root Password Please help me To recover my root password.i am not able update my system not able install new software.


I need to get name and supervisor name  Table name:user  id | name | -----------  1 | David   2 | Frank  3 | Shane  4 | Franchich   Another table name: details  user_id | supervisor_id| ----------------------------   1 | 4   2 | 3   3 | 4   I have tried like :  select      name as user name  from user, details  WHERE details.user_id=user.id    but failed   Now I want to get result like  User Name | Supervisor Name ------------------------------ David | Franchich Frank | Shane Shane | Franchich   So how is it possible ?


How to see a record of amendments to flight schedules?

My flight from Delhi to London with Virgin Atlantic was delayed by more than 5 hours on Thursday 18th April. I am trying to get the official takeoff and landing time for this flight but can't find it any more. Virgin have told me that they were delayed because they only knew that Pakistan Airspace was closed 4 days prior to the flight, but in reality they had been avoiding it since it was 1st closed in Feb 2019. There was an additional delay for technical reasons hence the 5 hours delay.


Removing an object from vector while iterating through it

I'm new to C++ so I'm having trouble figuring out how to best remove an object from a vector while still iterating through it.  Basically, I need to iterate through two vectors. For every item, if the ID's match, I can remove them.  //For every person, check to see if the available bags match:         for(std::vector<Person>::iterator pit = waitingPeopleVector.begin(); pit != waitingPeopleVector.end(); ++pit) {             for(std::vector<Bag>::iterator bit = waitingBagsVector.begin(); bit != waitingBagsVector.end(); ++bit) {                 int pId = pit->getId();                 int bId = bit->getId();                 if(pId == bId){                     //a match occurs, remove the bag and person                 }             }         }   Working with iterators is a bit confusing, I know I can use the .erase() function on my vectors, but I can't really pass pit or bit. Any help appreciated. Thanks


How can we prove the following relation for differentiating the wedge product of a p-form $\alpha_p$ and a q-form $\beta_q$$$d(\alpha_p\wedge\beta _q)=d\alpha_p\wedge\beta_q+(-1)^{p}\alpha_p\wedge d\beta_q$$


does the area under the curve (AUC) has some interpretation?

I know that the ROC curve plots true positives vs false positives, but does it have any other interpretation, or is it just an arbitrary performance measure? Also, in the case of very unbalanced response variable's classes (say 10 to 1) is an AUC of 0.5 still a bad thing?


Extract text between two characters (multiline input)

If I have the text:  aaaaaaaaa #some info other rows end row# another info   How could I extract only the text between the characters # obtaining only:  some info other rows end row   I was trying with sed in this way:  echo -e "aaaaaaaaa\n#some info\nother rows\nend row#\nanother info" | sed -n -e '/\#/,/\#/p'   but it gives me also the character #. Is there a way to remove # using sed?


Where can I find a list of ports for update to give to our ISP so that we can update Ubuntu Server 18.04?

Original title: Не могу обновить или установить пакеты Ubuntu server 18.04 Can't update or install packages on Ubuntu server 18.04. Internet provider Rostelecom, we sit behind their proxy server and content filtering. And so that we could work normally with Ubuntu server 18.04, they ask us to provide update ports. sources.list is not enough for them. Where can I see the list of ports??? Thank you in advance! Regards, Oleg.


Finding all $\mathbb Z$-module homomorphisms $\mathrm{Hom}(\mathbb Z/n\mathbb Z, \mathbb Z/m\mathbb Z)$

I am pretty sure that it has been already discussed many times, but I couldn't find.     Well, the problem is to show that $\mathrm{Hom}(\mathbb Z/n\mathbb Z, \mathbb Z/m\mathbb Z)\simeq\mathbb Z/(n,m)\mathbb Z$.   I have proven that $Hom(Z/nZ, Z/mZ)$ is precisely $Ann(nZ) = \{x \in Z/mZ: nx = 0\}. $ Thus my problem reduces to proving $Ann(nZ) = Z/(n,m)Z$, but I haven't gotten success so far.


Why didn't Han Solo stop Kylo Ren? (Spoilers)

So in Star Wars: The Force Awakens,      Han Solo dies, killed by his own son, Kylo Ren.   But there's something that's been bugging me about that.      Why didn't Han stop Kylo Ren (aka Ben) from killing him?     Here is the scene right after Kylo Ren says that he knows what he needs to do, but he needs his (Han's) help, and he hands Han his lightsaber, and drops his mask on the bridge. The thing is, as you can see in the picture, he holds the lightsaber horizontally, with the live end pointing to his right (Han's left). And Han has a hand on the weapon as well. So, practically, he would feel is Ren tried to turn the saber to the side, or to point it towards Han.  Ok, I'd understand if Han had died because Ren drove the 'sidebar' of his lightsaber through him. Eventhough Han had spent a lot of time around Luke, and was familiar with the lightsaber, Luke's lightsaber didn't have the sidebars. Han has probably seen Ren's unique lightsaber before, but I could accept that he forgot about the sidebars. This is if Ren had stabbed Han with the sidebar.    But in this scene, it's pretty obvious that Ren did not stab Han with the sidebar, but with the full length of the lightsaber. Which means that he must have turned it from facing his right to facing his front. And Han had his hand still on the lightsaber! So he must have felt Ren turning it around to face him.  Why didn't Han stop Ren killing him? If he was that much older and weaker than Ren and couldn't physically stop him, why didn't he just jump out of the way?   EDIT: In , it was asked if Han knew Ren was going to kill him. But that question addresses what was going through his mind as he confronted Ren solo (pun intended). My question is asking why he did let Ren kill him. It's as if he not only knew Ren was going to kill him, but he wanted it. Why?


Trying to identify book ("Companions"?) about bioengineered telepathic wolves and evil shape shifting alien (Zaar?)

Trying to identify book about woman who bioengineers giant telepathic wolves that have some kind of alien DNA spliced into them. The woman/scientist also has some wolf DNA spliced into her giving her a wolf's sense of smell. Her colleagues have more advanced adaptations enabling them to full body morph into wolves, the three scientists and three wolves make up a pack and they are on another world performing some kind of test.  The story flashes back to memories of how the lead scientist got to where she is today, remembering her time working for another alien race that called other races "vermin" in their own language and a friend she had of that alien race called her by a nickname that meant "acceptable vermin".  There is also a section of the story following a high ranking male in the political structure of a race of lizard-men. This race starts out very stupid bit individuals gain intelligence and comprehension with age as they loose their blood-lust. A warring race with no real culture, the oldest males rule the geopolitics of the planet with some interference by a bug like race. The females are as witless as cows. But this high-ranking male, while performing a ceremony to claim several new sons to raise from a clutch, decides to dispatch the unworthy offspring himself as an afterthought, and walks in on a technician of some sort lobotomizing the female hatchlings.  Turns out the females are the smart ones and the bug race put this custom in effect to control the lizard men. It hints at a greater story there but never quite circles back, going back to the woman and the wolves and some threat of an ancient alien shapeshifter, i believe called Zaag or Zaar or something like that. Turns out the D.N.A. spliced into the wolves came from that race of aliens and are evil, the charismatic wolf alpha who has scent glands in the roof of his mouth used for "speech" via smell, is this zaarg alien character, perhaps somehow reincarnated or reconstituted from the bioengineered cells?  I cant remember much else. And all of this is through the scientist woman's memories as she waits outside a door to speak to someone, and stops to wash her face at a basin to wash away tears and calm herself. I thought the book was called "Companions" but haven't been able to find it in years. I read it probably 10 years ago from my local library. They no longer have it or know what book it was. I want to reread it as an adult and see if its a good as i remember. It seemed like it would've been the first book in a series. Please help.


Comments that are just a link are non-deletable on mobile

On the Stack Exchange iPhone app, to bring up the small menu beneath a comment with delete, reply, etc., we touch an area of text within the comment (touching a name or link will navigate to the commenter’s profile or URL respectively) But when a comment is just a URL, there appears to be nowhere to touch the comment in order to bring up the menu (since it will navigate to the URL). Hence the comment cannot be deleted, flagged, etc. Example below


VS-Code, using regex in Find All (Ctrl + Shift + F)

I am unable to use regex in the Find All. I have turned regex on but it is not finding any results I am looking for code that is: returnValue = !$(someClass.someVariable).isDisplayed();  with the part someClass.someVariable being the wild card in my case and I am trying to use the regex: returnValue = !$(.*)isDisplayed();


how can i get a blob from mysql and show in a jtextpane?

I am trying to show a image from mysql in a jtextpane but doesn't work,the problem appears when I try to turn the inputstream into BufferedImage, could you help me?  private void initialize() {     frame = new JFrame();     frame.setBounds(100, 100, 508, 300);     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);     frame.getContentPane().setLayout(null);      JTextPane textPane = new JTextPane();     textPane.setEditable(false);     textPane.setBounds(55, 40, 370, 192);     frame.getContentPane().add(textPane);      try{         Statement a = (Statement) con.createStatement();         ResultSet b = a.executeQuery("Select imagen from chat");         InputStream i = null;         ImageIcon ii = null;         if (b.next()) {             i = b.getBinaryStream("imagen");             BufferedImage bi = ImageIO.read(i);             ii = new ImageIcon(bi);             textPane.insertIcon(ii);         }     } catch ( SQLException | IOException e) {          // TODO Auto-generated catch block          e.printStackTrace();      }   }   the console said...  java.lang.NullPointerException at javax.swing.ImageIcon.<init>(Unknown Source) at imagen.initialize(imagen.java:75)   I can't find the solution


I download a project source code using git clone.  The project I downloaded contains many subfolder.  I want to know the git path of a given sub folder in order to download only this subfolder using git clone  How to do it?


"grey" vs "gray" are both common equally in use?

Yesterday I wrote "gray" in the meaning of the color, but my friend corrected me and told me to write "grey". Today I checked in the  and I found that they are both correct for the same meaning. So, now I just have doubt which one of them is more common in use.


Converse of "localization at a prime is local"

Suppose $S^{-1}R$ is the localization of a ring R at a multiplicative subset S, and is local. Must S be the complement of a prime ideal?


Prove: if $d=\text{gcd}(m,n)$ so $\text{gcd}\left(\frac{m}{d},\frac{n}{d}\right)=1$

$$\newcommand{\gcd}{\text{gcd}}$$     Prove: if $d=\gcd(m,n)$ so $\gcd\left(\frac{m}{d},\frac{n}{d}\right)=1$   Intuitively it is obvious, but I am having a hard time to formalize the proof, what I have came to this:  $d=\gcd(m,n)$ so $d|m$ and $d|n$ therefore $m=dx$ and $n=dy$ now if $\gcd\left(\frac{m}{d},\frac{n}{d}\right)\neq 1$ that mean that $m$ and $n$ have a common factor, after the division in $d$ which is the greatest common divisor is contradiction.


How to reverse the assignment of values to keys in a dictionary? solve the algorithm

The groups_per_user function receives a dictionary, which contains group names with the list of users. Like the groups in Linux system. Users can belong to multiple groups. Fill in the blanks to return a dictionary with the users as keys and a list of their groups as values. basically I'm trying to reverse the assignment of groups to users instead of users to groups That's what I have tried so far: def groups_per_user(group_dictionary):     user_groups = {}     groups = []     # Go through group_dictionary     for group,users in group_dictionary.items():         # Now go through the users in the group         for user in users:         # Now add the group to the list of           # groups for this user, creating the entry           # in the dictionary if necessary           groups.append(group)           user_groups[user] = group      return(user_groups)  print(groups_per_user({"local": ["admin", "userA"],         "public":  ["admin", "userB"],         "administrator": ["admin"] }))  How can I traverse throw the list and at the same time add the user to the group name as efficient as possible? Please excuse my grammars, that's my fist question here. Thank you


Modifying some features on the graphs of a function and its inverse

The following code is compiled by pgfplots to graph an exponential function and its inverse. I have some questions about the code, and I would like to modify some of the features of the graphs.  How is pgfplots instructed to draw grid lines 5 units apart? Why is the graph of the exponential function between the vertical lines x=-5 and x=3.8, I guess?  Why is the graph of the line y=x between the vertical lines x=-5 and x=5?  Why does the label for the logarithmic function interfere with the graph of the logarithmic function?  I would like the numbers on the axes to be in white nodes - so that the grid lines are not drawn over them.  The grid lines are drawn too high and too far to the right. I would like either the grid lines to be drawn a bit shorter or the axes to be drawn a bit longer.  The domain of the exponential function (that is graphed) should be from -6 to 4, and the domain of the linear function should be from -6 to 16.  \documentclass[10pt]{amsart} \usepackage{tikz} \usetikzlibrary{calc,angles,positioning,intersections,quotes,decorations.markings} \usepackage{tkz-euclide} \usetkzobj{all} \usepackage{pgfplots} \pgfplotsset{compat=1.11}    \begin{document} \begin{tikzpicture} \begin{axis}[grid=both,           xmax=18,ymax=17,           axis lines=middle,           restrict y to domain=-7:17,           enlargelimits] \addplot[dashed]{x} node[fill=white, above, right]{$y=x$}; \addplot[green]  {pow(2,x)} node[fill=white, above, right]{$y=2^x$}; \addplot[blue,domain=1/2^6:16,samples=100]  {log2(x)} node[fill=white, below] {$y=\log_2(x)$}; \end{axis} \end{tikzpicture}  \end{document}


Consequences of a master thesis with errors

I finished my master thesis 6 years ago, since then I gained a lot of experience on my field and also in academia. I can say that in that time I was a "child" , very inexperienced. I think that also my advisor did not help a lot, and I tried to do  a lot of things by my own, without someone to really review my things. Despite that, I still received a good mention by the master committee on final results.   Some days ago, I just decided to read part of master thesis, and I just realized a big nightmare coming. I identified a lot of typos, some references errors, and some improvements that I should do, but I did not. The worst thing is that I wrote a paper to a conference with my master thesis results (and some errors are there). The conference is not a high impact conference, but still the paper has my name and is available for everyone...   As I am finishing my PhD studies for now, I am concerning a lot that situation. My dream and goal is to pursue a Professor career. So, my questions are: What are (or could be) the consequences of a master thesis and paper with errors (some minor and some major) in academia? Revoke degree after years by errors in master is possible ( I am concerning a lot this situation that I thought on it)? How can I minimize it (I thought that I can put a fixed version of my thesis and paper in the future, for instance on my personal website)? How those errors can impact me in a Professor recruitment process?  Sorry for the long text, I am blaming myself all the time, and really afraid about the possibilities since I know that Academia career is really competitive.


If $f(xy)=f(x)f(y)$ then show that $f(x) = x^t$ for some t

Let  $f(xy) =f(x)f(y)$ for all $x,y\geq 0$. Show that $f(x) = x^p$ for some $p$.    I am not very experienced with proof. If we let $g(x)=\log (f(x))$ then this is the same as  $g(xy) = g(x) + g(y)$   I looked up the hint and it says let $g(x) = \log f(a^x) $   The wikipedia page for functional equations only states the form of the solutions without proof.  Attempt  Using the hint (which was like pulling a rabbit out of the hat)  Restricting the codomain $f:(0,+\infty)\rightarrow (0,+\infty)$ so that we can define the real function $g(x) =  \log f(a^x)$ and we have $$g(x+y) = g(x)+ g(y)$$   i.e $g(x) = xg(1)$ as $g(x)$ is continuous (assuming $f$ is).  Letting $\log_a f(a) = p$ we get $f(a^x) =a^p $. I do not have a rigorous argument but I think I can conclude that $f(x) = x^p$ (please fill any holes or unspecified assumptions) Different solutions are invited


What is a good mnemonic rule that an English learner can use to remember the difference between its (possessive adjective: a team has started its lunch) and it's (verb: it's raining)?


Why are the Rebels still called rebels in the The Force Awakens and The Last Jedi?

In the original trilogy (A New Hope, Empire Strikes Back, Return Of The Jedi) calling Luke, Leia, Hans, etc made sense.  They're rebelling against an evil empire.  In the latest set of Star Wars movies, they are still called The Resistance (and generally see themselves as such), and the First Order routinely calls them "Rebel scum".  Except if my understanding of the plot is correct The First Order is actually the rebel scum! They destroyed the capital, then used their fleet of ships to began taking control of the galaxy in between The Force Awakens and The Last Jedi.  It seems like it would make more sense for the First Order to use "democratic scum", "government scum".  Even during a civil or revolutionary war, the insurgents don't call the other side rebels - they call them Brits, Northerners, etc, not rebels.  Has this ever been addressed either in Star Wars media or in cast and crew interview?  EDIT: Out of universe calling people rebel scum is part of Star Wars.  There is a reason  - I wondered if this is the same.


Cannot catch access violation exception by use of C++ catch(...)

In the following code I want to catch either asynchronous and synchronous exceptions by use of c++ catch (...) according  descriptions about Exception Handling Model. Also I set the "Exception Handling Model" up to Yes with SEH Exceptions (/EHa) value. I tested the code with the following states respectively :  When I copy a string in an unallocated char* (char *c;), then i can catch its exception in catch (...) section. (However I know this is an undefined behavior!)  But when I copy a string in an array of characters (the string is larger than the array size), then I can't catch any exception !!  In the 2nd state, while debugging I got Access Violation error. but why cannot catch its exception like the 1st state ??  I tried another solutions as mentioned in :    But also The problem persists.  This is my code (I tested strcpy() either on an unallocated char* and  on an array of characters): int main() {     char c[3] = { 0 };        // Cannot catch any exception     //char *c;                // Can catch exception      try     {         strcpy(c, "abcdefghijklmnopqrstuvwxyz1234567890");     }     catch (...)     {         cout << "Undefined behavior!" << endl;     }      return 0; }


How can I get more doc in lucene4.Here is my code.  int limit = 1000; TopFieldColletor collector = TopFieldColletor.create(sort,limit,true,false,false,false); searcher.search(query,collector); ScoreDoc[] sds = collector.topDocs().scoreDocs; System.out.println("sd:" + sds.length);    System.out.println("total:" + collector.getTotalHits());   This is my result: sd:1000 total:9060 My question is I got the 1000 doc, how to get the next 1000, until the end to take.


Domain, Codomain, Range, Image and Preimage

Can someone please explain to me in layman what each means? Perhaps with some examples with functions (inputs to outputs/numeric values in them)? Especially range, image, and preimage. So far this is my understanding:   Domain is basically the input $x$ in $f(x)$. Codomain is what $f(x)$ produces as an output such as $y$ when $f(x) = y$. Range sounds like codomain but with some restriction?  Image I have little understanding of but I think it is basically a relation between domain to codomain given that we take a subset of our function (Eg; it is the input to output process of our function given we put a restriction on the domain as $x$ can only go from $0$ to $1$).  Preimage is just walking backward on the "image" process? (Inverse image?) Going from our "subsetted" output back to our "subsetted" input?    I am very frustrated that I can't seem to grasp these basic concepts so I would greatly appreciate any help from anyone who can break this down for me and help me understand it without too much mathematical notation. Thank you!


Homology of $S^2/x\sim -x$ for $x$ on the equator

Let $X$ be the quotient space of $S^2$ under the identifications $x\sim -x$ for $x$ in the equator $S^1$. Compute the homology groups $H_i(X)$.   I wrote my solution/attempt below and I would like to know if it it correct and, more importantly, if there is a simpler solution. I tried using cellular homology but I'm not very experienced with it and kept getting nonsense.   Here is my attempt:  $X$ can be written as the following pushout: $$\begin{align*}  \require{AMScd}  \begin{CD}   P^1 @>{i}>> P^2\\   @V{i}VV @VVV \\   P^2 @>>> X  \end{CD} \end{align*}$$ where $i:P^1\hookrightarrow P^2$ is the inclusion. So by a Mayer Vietoris argument, we have $H_i(X,P^2) \approx H_i(P^2, P^1)$. This can be simplified to $\tilde{H}_i(P^2/P^1) \approx \tilde{H}_i(S^2)$. Now we consider the LES of the pair $(X, P^2)$. $$0\to H_2(P^2)\to H_2(X)\to H_2(X, P^2)\to H_1(P^2)\to H_1(X) \to 0$$ We know all homology groups involved except those of $X$, so the LES reads: $$0\to \Bbb{Z}\to H_2(X) \to \Bbb{Z}\to \Bbb{Z}_2\to H_1(X)\to 0$$  The problem lies in identifying the map $\Bbb{Z}\to \Bbb{Z}_2$, call it $f$. The LES tells us that $H_1(X)\approx \Bbb{Z}_2/\text{im }f$. On the other hand, by the Van Kampen theorem for attaching 2-cells, $X$ can be viewed as $P^2$ with a 2-disk attached along the path $aa$, hence $\pi_1(X)\approx \Bbb{Z}_2$. This is abelian, so it coincides with $H_1(X)$. Then $f$ must be the $0$ map. Using that, from the LES we can also compute $H_2(X) \approx \ker f \oplus \Bbb{Z}\approx \Bbb{Z}^2$.


If $f(x)$ is a quadratic expression such that $f(x) > 0,\ x\in\mathbb{R}$ and if $g(x)= f(x) + f'(x) + f''(x)$, then prove that $g(x) > 0, \ x\in\mathbb{R}$.


I want to avoid text being italicized when it's inside dollar signs. For example I want the Gal part of $Gal(f)$ to show as plain text, without having to write Gal$(f)$. How do I do this?  Thanks.


Why I still can execute bash file without x permission?

I made a bash file "my_sh.sh". by default it has no x permission:  -rw-rw-r-- 1 amin amin 37 Mar 12 00:45 my_sh.sh   But I could run it without any problem or warning! Why?  amin@ubuntu:~/newDIR$ bash my_sh.sh


If $p$ is a prime of the form $4k+3$ and $n$ is any integer, then $p$ doesn't divide $n^2+1$.  The "$p$ doesn't divide $n^2+1$" part is giving me real trouble when trying to prove this.  Any help or hints with the problem is appreciated.


I need to calculate the following indefinite integral:  $$I=\int \frac{1}{\cos^3(x)}dx$$  I know what the result is (from Mathematica):  $$I=\tanh^{-1}(\tan(x/2))+(1/2)\sec(x)\tan(x)$$  but I don't know how to integrate it myself. I have been trying some substitutions to no avail.   Equivalently, I need to know how to compute:  $$I=\int \sqrt{1+z^2}dz$$  which follows after making the change of variables $z=\tan x$.


$AB-BA$ is a nilpotent matrix if it commutes with $A$

I saw this in a  and am putting it here for posterity.  Problem: Let $A$ and $B$ by square matrices and set $C=AB-BA$. If $AC=CA$, prove $C$ is nilpotent.


I'm wanting to know what the thinnest tires i can put on my gravel bike are

I'm looking to buy thinner tires for my gravel bike my bike has Weinmann U28 TL rims and right now has 700*40mm tires do I need to buy new rims to put 30mm tires in. On Weinmann's website, they say the  U28 TL doesn't come in a 700c variant so I can't find it there. The bike is a 2020 Khs grit 220 if that helps at all


I have a problem with python3.6 idle. I think I installed some package in the past and since then I have a problem installing other problems because whatever I try to install it shows me the same error, even if I try to unistall python it shows me this:  idle : Depends: idle-python3.6 but it is not going to be installed   I've tried to unistall python but I got this error. What should I do???


What type of displacement is virtual displacement? Is it really a displacement? How to calculate it?

Searched this question a lot in different places but could not find any answer that could satisfy me. So I am here to clear my concepts regarding virtual displacement. Now I am clarifying my doubt. As my textbook "A Student’s Guide to Lagrangians and Hamiltonians" by Hamill says on p.11:  A virtual displacement, $δx_i$, is defined as an infinitesimal, instantaneous displacement of the coordinate $x_i$, consistent with any constraints acting on the system.  And it gives the relationship, $$\delta x_i=\sum_{\alpha=1}^n\frac {\delta x_i}{\delta q_\alpha}$$ The time co-ordinate is frozen in virtual displacement. Now my question is if time is frozen then no displacement should occur. So how the "Virtual displacement" come? What does it mean? Again $\frac {\delta x_i}{\delta q_\alpha}$ how is it getting the dimension of a displacement? I think the $x$'s and $q$'s dimension is same [L]. So it should be dimensionless. Please illustrate it so that I do not face any difficulties with virtula-displacement term. I will be too much helpful if you also give an example to show how to calculate virtual displacement.


a large amount of the population speaks/speak?

Can you say "a large amount of the population" or should it be "a large number of the population? And if you CAN say "a large amount of the population" is this amount considered singular or plural?


Setting file contents with newlines and other special characters as environment variable with interpretation of included variables

Given I would like create environment variables from files containing newlines and special characters. The clue is that this content can have references to other environment variables which have to be intepreted. Maybe I need more complex tools than just plain bash?  A testfile "testfile.txt" could look like:  * foo \/-!~  FOO=${FOOBAR}   What I have managed myself so far is the following:  #!/bin/bash FOOBAR="SUCCESS" file="testfile.txt" var_name="TEST" name="$file" content="$(<$file)" echo "$content"   Which gives me a context variable as output (so, exactly the contents of the file):  * foo \/-!~ FOO=${FOOBAR}   But, how can I:   Let ${FOOBAR} be set to "SUCCESS" as defined above but do not touch the rest? Set an environment variable TEST  which would have content as (1)?


If $z_1+z_2+z_3=0$ and $|z_1|=|z_2|=|z_3|=1$, then $z_1,z_2,z_3$ are the vertices of an equilateral triangle.

Suppose that $z_1+z_2+z_3=0$ and $|z_1|=|z_2|=|z_3|=1$. I want to prove that $z_1,z_2,z_3$ are the vertices of an equilateral triangle.  We can assume that $z_1\neq0$. Thus $1+\frac{z_2}{z_1}+\frac{z_3}{z_1}=0$ and  $|\frac{z_2}{z_1}|=|\frac{z_3}{z_1}|=1$.  I can prove that if $1+z_2+z_3=0$ and $|z_2|=|z_3|=1$, then $1,z_2,z_3$ are vertices of an equilateral triangle.  So back to original problem we can conclude that $1,\frac{z_2}{z_1},\frac{z_3}{z_1}$ are vertices of an equilateral triangle. Could you give me some hint to continue from here? Thanks!


I have read in an introduction to quaternions that it had been proven before that one can not structure the Euclidian $\mathbb{R}^3$ as a field.   Where can one find a proof thereof?  For which n, could we bestow $\mathbb{R}^n$ with a field structure?


Mention a specific potential adviser and project in the PhD statement of purpose

I am writing my statement of purpose for my Ph.D. and I want to work in a specific field with a specific professor in the department that I am going to apply for and I have a very good experience in this field. I sent an email for that professor asking if he/she is accepting Ph.D. students and he/she did not respond. I built my whole statement of purpose based on my previous achievements and future plan for that specific area. I also mentioned that I am willing to work with that professor. My statement of purpose tells that I am very passionate about this field and I am only willing to work with that professor (if there were more than one professor working on the same area, I would mention all of them). if that professor doesn't accept new Ph.D. students, will I risk my admission to that school?   Will the committee response be something like this:  "the applicant really knows what he/she is going to do and there is a specific future plan and he/she also got a good experience in this field, but he/she sounds very strict to his plan and doesn't show any flexibility...REJECTED"?


Mirror menu items from the Shift + Right Click in the Right Click context menu

When you hold Shift and press Right Click in Windows Explorer you get some additional menu items, most prominently the options to open the directory in cmd or the PowerShell. I once made these menu items available in the normal right click context menu by manipulating the registry. Unfortunately, I cannot find the tutorial on how to add additional items to this menu anymore. The only thing I do find is "How to reenable the 'open cmd here' context menu item". I think the last windows update wiped these entries I added for the WSL bash and cmd from the context menu. Now, these entries are only available when I hold Shift while right clicking. How do I get the normal entries back, i. e. how do I get context menu items for "Open cmd here in Windows 10 Windows Explorer" in the normal right click context menu?


Random unique alpha numeric string in java

I want to generate a string mix of numbers-capital and small characters but they should be unique with a specific length Is there any algorithm or library in java to generate unique strings?


I think I read it during a battle of the books event in Alaska in the 1999-2002 range. The story is about a kid who finds a house where everything is wonderful and perfect, and morning is always spring, noon is summer, afternoon is autumn and nighttime is winter. Every night they all open presents like its Christmas and its just perfect. All the kids speak of Mr./Ms ____ who runs the house but none of the kids have ever seen them. I remember a pair of quotes where the protagonist realizes that "Mr. __ WAS the house!" and then later, when there ends up a war as some of the kids try to escape, the house itself starts to attack them with the phrase, "The house became Mr. ___". Eventually some of the kids escape and find out they have been missing for years. As many years as they had days in the house. And one girl turned into a fish... I think, my memory on that bit is super vague.


I want to know more about this specific perpetuum mobile

Sorry for beeing another noob asking stupid questions, but I just wanna know more about this specific perpetuum mobile.  I don t say I full understand the math, but I cant disagree with something that history proved that is alwasy right. I just want that someone explain and draw for me the balanced state of the system which I can t find jow hard i would try. Srry for my English, I am not a native speaker.


I have found a diagram similar to the following one in my biology textbook. The diagram describes allosteric regulation.    However, I do not quite understand why the maximum reaction rate $V_{max}$ is still reached, even though I thought this is only possible for a competitive inhibition.   I think that the diagram should look something like this where the maximum reaction rate is not reached.    Is there simply an error in the diagram or have I misunderstood something here?


Can chmod on a directory without --recursive change who can read a file within that directory?

Based on the suggested duplicate, let me reformulate my question:  If chmod 0660 path/to/folder is run, and user A isn't in the relevant group, could user A still read /path/to/folder/file.txt if that file has the appropriate octal?


Will the Helios 44-2 lens work on Nikon D3300?

I would like to buy a Helios 44-2 lens, but I need to know if my Nikon D3300 will allow me to take pictures with it since the lens has no pins. Will there be any other problems?


Name Server does not change my web site IP address

I'm new about the config of the web server.  I asked my hosting company to set the DNS to point to my VALID IP address, in the university. My server is ubuntu 12.04 (desktop). I installed apache2 and bind9. Now the ns ping points to my IP (217.218.245.169), but when I ping my web site (ijnrs.com), it points to its previous IP address (5.61.27.195). I have included the db.ijnrs.com file. Would you please help me. I want www.ijnrs.com (and ijnrs.com) points to my IP address.  EDIT: I'm aware that it takes some time for IP addresses to be propagated, however, I can now ping ns.ijnrs.com and see the desired IP addressees, while the main address is not accessible. My question was about the difference between the way these names and IP addressees propagate.   Thanks.  db.ijnrs.com  ; ; BIND data file for local loopback interface ; $TTL    604800 @       IN      SOA     ns.ijnrs.com. root.ijnrs.com. (                              35         ; Serial                          604800         ; Refresh                           86400         ; Retry                         2419200         ; Expire                          604800 )       ; Negative Cache TTL ; ijnrs.com.      IN      NS      ns.ijnrs.com. @               IN      NS      ns.ijnrs.com. @               IN      A       217.218.245.169 ns              IN      A       217.218.245.169 www             IN      CNAME   ijnrs.com.


Updating intel microcode before installation?

I'm attempting to install Ubuntu (I've tried 16.04, 17.10 and 18.04 daily build). Each time I encounter an error when the image is booting, something along the lines of TSC_DEADLINE error, update microcode. I've read some people have had success with updating their motherboard bios but this didn't help me, unfortunately. Other solutions appear to be related to those who already have Ubuntu installed.  Is there a way to alter the iso with the new microcode before installation?  Thanks for any help.


Find $a,b \in \mathbb{N}$ with $\mathrm{lcm}(a,b)=12\gcd(a,b)\,$ and $\,a\bmod b = 5$

Find $a,b \in\mathbb{N}$ such that:      Remainder of $a$ divided by $b$ equals $5$       $\mathrm{lcm}(a,b)=12\gcd(a,b)$   I don't know how or where to start. The most similar problem I found was  Still I can't figoure out how to solve my problem, any help will be appreciated, thanks.


problems in doing logistic regression with unbalanced sample, give me some references

I have a dataset with lots Y=0 and few Y=1. I have to run logistic regression, so I'm using a retrospective sample in order to get a more balanced sample. Could someone give me some references that explain which are the problems arising when I use logistic regression in an unbalanced sample? I kwow that the main problems are instability of estimated coefficients and poor predictive power of the model, but I need some references.


Firefox: download all file types without prompt

I am trying to set the default behavior for downloading files in Firefox. Currently it opens a nasty dialog "open with or save", and i can tick a checkbox to perform selected action for this mimetype in future.  What I want, is to save files without opening any dialogs for all, even unknown mimetypes (just ignoring what the type is). I know there is browser.altClickSave option, i need its behavior for simple click. It's ok if the solution will first check mimetype preferences or ignore them.  Please don't tell me to add entries to mimetypes.rdf file in profile, this is just a hack. AFAIK it does not allow to set default or wildcard. By the way, it is very unreliable to edit this because i have to do it by hand (Firefox lacks functionality of adding/removing entries in Settings->Applications list).  Also please don't discuss security of the mentioned dialog for new types downloads, i basically don't run every file that i download.  If it is not possible to do with bare firefox, any solution with extensions is ok. Using macros is not good because we will waste time on opening dialog and waiting for "ok" button to be active for 3 seconds.


When I run this code, it prints 0 , 1, 2, but I have no idea why. could you explain me?  public void run() {         int[] arr =  new int [3];         for(int i=0; i<arr.length;i++){             arr[i]=i;         }         domore(arr);         for(int i=0; i<arr.length;i++){             println(arr[i]);         }     }      private void domore(int[] arr) {         // TODO Auto-generated method stub         int [] att = new int [3];         for(int i=0; i<att.length;i++){             att[i]=77;         }         arr=att;     }


If $f:\mathbb{R}\rightarrow \mathbb{R}$ is continuous, 1-1, and on-to, then f maps Borel Sets to Borel Sets

Let $f:\mathbb{R}\rightarrow \mathbb{R}$ be continuous, on-to, and 1-1. Prove that if $A$ is a Borel set, then $f(A)$ is a Borel set.


Can someone explain why "B1" cell is not vertically centered and how to figure this out ?  \documentclass{article}  \usepackage{array} \usepackage{amsmath}  \begin{document}  \newcolumntype{A}{>{\centering\arraybackslash}m{.2\textwidth}} \newcolumntype{B}{>{\centering\arraybackslash}m{.3\textwidth}} \newcolumntype{C}{>{\centering\arraybackslash}m{.2\textwidth}} \newcolumntype{D}{>{\centering\arraybackslash}m{.15\textwidth}}  \begin{tabular}{|A|B|C|D|} \hline C1 & C2 & C3 & C4 \\  \hline Type 1 &   $\begin{matrix}  eq_1 \\  eq_2  \end{matrix}$  & A1  & B1 \\[3cm] \hline \end{tabular}  \end{document}   Thanks.


Ubuntu 17.10 won't allow me to remote access my desktop via TeamViewer

I have TeamViewer 12 installed on my a few computers around the office. On a Windows 10 machine, 2 Linux Mint ones, my mobile and Ubuntu 17.10. And I can access everything from everything except Ubuntu 17.10.   Every time I try to remote access Ubuntu's desktop all I get is:   ERROR   No connection to partner. Partner did not connect to router. Error code: Wait for network failed.    That, even though the Ubuntu PC is online and the TeamViewer client on it perfectly functional. I can have a meeting or a chat using teamviewer but it simply refuses to let me remote control the Ubuntu pc.  So to get this right, after Ubuntu devs broke the default state of several popular programs including Steam Client now they're breaking team viewer too? Just stop pushing users away from your own product.  But back to the topic: Any idea about how I could get this fixed? I tried a few things including restarting daemon but nothing worked. Any advice aside replacing Ubuntu with Mint that I already have in mind would be most appreciated. Thank you!


Can "who" as a relative pronoun sometimes be omitted?

Somebody once observed two things:   people often omit the relative pronoun "who" or "whom" to avoid having to worry about which is grammatically correct however, in all cases where it can be omitted, it is "whom".   But look at this sentence:     I have a friend I hope will come.   Would you consider this to be grammatical, and therefore a counterexample to the latter point?


Just upgraded from 18.10 to 19.04 in HP Elitebook but orientation option is missing in display setting and display is messed up

Just upgraded from 18.10 to 19.04 in HP Elitebook  The orientation option is missing in display settings. The display is upside down.   Do I need to install anything to fix it?


"Net Send" command into Microsoft server 2008 r2

I remember with the old windows server was able to send messages with the command "NET SEND", now I am using "Windows 2008 R2" and this feature is not active.  Can you give me some additional suggestions to send messages to clients of my domain.   From the forums I read that it possible use the MSG command, but it is not very clear.   Domain Name: Domain   Workstation Name: PC1


Why does all points $(x,y)$ satisfying $ax+by=c$ stay on a straight line?

We know that points $(x_i,y_i)$ which satisfy the equation $ax_i+by_i=c$ lie on the same straight line. I understand that all points on this line satisfy the equation, but how do we ensure that all points satisfying the equation stay on the same line? As @saulspatz says,  How do we know that the lines defined by analytic geometry satisfy the Euclidean axioms?


How does one find the reduced Singular Value Decomposition of a row or column vector?

If we treat a column vector $a$ as an $n \times 1$ matrix, or a row vector $a^T$ as a $1 \times n$ matrix, how would one write out the reduced singular value decomposition of $a$?


I will be travelling from Belgrade in Serbia to London UK in a few weeks. There is a stopover at Instanbul in Turkey.   Given the recent laptop travel ban, I probably be required to put my laptop in cargo. I am wondering whether anyone knows if it is possible to insure the laptop against damage or theft while on the cargo of the plane.


Ubuntu 12.04 won't come with the Windows Installer (Wubi) pre-added. But is there any way to install 12.04 using Wubi?


Quick question as I can't seem to find a question regarding installing Ubuntu alongside Windows 10.  I've followed the instructions in the Ubuntu installation documentation as I'd like to install Ubtunu alongside windows 10, at least until I get the hang of Ubuntu. However, I can't find the UEFI editor in Windows 10 at all. (It isn't displayed where the tutorials say it is).  So, my question is, what is the best way for me to have both Ubuntu and windows 10?  Thanks in advance,  Nic


Recently I was reading about magic methods in Python, which make the code a lot easier to read. Can we define our own mappings? If so, is there any pointer for this and how complicated it would be?  For example, + is always mapped to __add__. Could I define a mapping for ?, which would call __is_valid__ in my class?  c = Car() print(c?)  # invokes __is_valid__ of Car to get the result


Can I treat an unarmed strike as a "Light weapon" in terms of two-weapon fighting?

Player's Handbook page 195:     Two-weapon fighting   When you take the Attack action and attack with a light   melee weapon that you're holding in one hand, you can   use a bonus action to attack with a different light melee   weapon that you're holding in the other hand. You don't   add your ability modifier to the damage of the bonus   attack, unless that modifier is negative.   If either weapon has the thrown property, you   can throw the weapon, instead of making a melee   attack with it.   What if a character:   holds a light weapon in one hand, and nothing in the other hand fights with bare fists (not being a monk)   Can they use the bonus action for a second attack?


Proving $\sum_\limits{k=0}^n \binom {k+m} {k} = \binom {m+n+1} {n}$ by induction.

$\sum_\limits{k=0}^n \binom {k+m} {k} = \binom {m+n+1} {n}$, where $n, m \in \Bbb N$.  I missed two lectures due to illness and now have this for homework. I am completely out of my depth, mostly due to there being  a second variable to deal with.


How to force Windows to rename a file with a special character?

I have a song that Windows can't play because there is a question mark in the name of the file.  "Where Have All the Cowboys Gone?.ogg" // as an example   So I try to rename it and Windows complains whether I try it in Explorer or from command prompt.  Error I get when trying to copy, rename, or move is:     The Filename, directory name, or volume label syntax is incorrect   Is there a Windows way to force a rename in this case?   Update  I'll keep an eye on this question, but after 13 answers and many attempts (aside form 3rd party solutions) it seems that Windows can't do this (or at least my windows can't, no short names). So I'm accepting the answer which was my original solution anyway of using Linux. It would be nice to see Windows handle this somehow, so don't stop just because I've accepted this answer, the question still stands!


The command dpkg -l is used to list all installed packages in the system.  But if you look to the output such as below:  ii  whoopsie       0.1.34         Ubuntu crash database submission daemon rc  wicd-daemon    1.7.2.3-1ubunt wired and wireless network manager - daemon rc  wicd-gtk       1.7.2.3-1ubunt wired and wireless network manager - GTK+ cl ii  winbind        2:3.6.3-2ubunt Samba nameservice integration server ii  wine           1:1.7.18-0ubun Microsoft Windows Compatibility Layer (meta- ii  wine-gecko2.21 2.21-0ubuntu1~ Microsoft Windows compatibility layer (embed ii  wine-gecko2.21 2.21-0ubuntu1~ Microsoft Windows compatibility layer (embed ii  wine-mono0.0.8 0.0.8-0ubuntu1 Microsoft Windows compatibility layer (.NET  rc  wine1.4        1.4.1-0ubuntu1 Microsoft Windows Compatibility Layer (Binar rc  wine1.4-amd64  1.4.1-0ubuntu1 Microsoft Windows Compatibility Layer (64-bi rc  wine1.4-i386:i 1.4.1-0ubuntu1 Microsoft Windows Compatibility Layer (32-bi ii  wine1.6        1:1.6.1-0ubunt Microsoft Windows Compatibility Layer (Binar   you can see the first element is either ii or rc.  So my question what is the meaning of  ii and rc?


cat a file containing "?" in command substitution

To automate access to my scanner, I'm trying to cat the output of scanimage -L into a Bash variable. In fact I was successfully doing this until recently with siL="$(scanimage -L | grep net | awk '{ print $2 }' )" in my , getting me addresses like hpaio:/net/ENVY_5530_series?ip=192.168.43.249 stored in $siL. I've today noticed an odd glitch which I've reduced to a minimum example here following. Given a file lines containing just this text: LINE1 LINE2_this_string_containing_an_embedded_question_mark_-> here?itis <-_doesn't_appear_if_cat_is_invoked_via_command_substitution LINE3  cat lines correctly shows the file, but $ L="$(cat lines)"; echo $L LINE1 LINE2_this_string_containing_an_embedded_question_mark_-> <-_doesn't_appear_if_cat_is_invoked_via_command_substitution LINE3  (and the same if I replace cat with <). Why is that word containing the question mark omitted?


This is a real story.  About 6 months ago, someone asked me to help her to solve her financial problem. I didn't know about her at all. At that time, I replied as ... Sorry, I want to help you but I can't .... She asked me to help her again, but I declined again.  She is an USA Air Force Officer.  Yesterday, I received a beautiful letter from her.     Hello my dear friend      It is my pleasure to reach you after our successful attempt on the   transaction. Well, i just want to use this medium to thank you very   much for your earlier assistance in the past to help me in receiving   the fund, I am obliged to inform you that i have succeeded in   transferring the fund with the help of a new partner from Canada.   everything was perfectly done because we stroke a deal with one of the   Lady accountant who works with the Federal Ministry of Finance, and   she rendered tremendous help to us.      You have to contact [SomeOne] to send you the ATM visa card i kept for   your compensation, the amount on the ATM is Nine hundred and fifty   thousand united state dollars ( $950,000 USD ) and your pin code is   (XXXX) thank you for all your effort and how you tried to help me, i   believe this money will solve some of your financial problem,      If you cannot travel to meet [SomeOne] in Senegal you can send him   your personal contact address where to post the Atm card to you   through dhl or ups, remember that i had giving him instruction to   release the ATM for you once you been in contact with him. once you   received the Atm remember to inform me so we can share the joy   together,      His name: someone      Email: [removed]      Phone Number: [removed]      Sincerely, Sgt Dr xxx xxxx   Is this possible?  I can't understand current situation?  How can I handle this situation?


I'm new to iTunes and everything doesn't make sense for me. I need to do backup of contacts, photos and music on my iPhone.  I've tried to follow several manuals how to do backup on my Windows PC but can't pass few steps.   My iPhone is connected by USB cable and is detected by iTunes I can't select anything from iTunes -> File -> Devices as all functions are grayed out In many manuals peoples refer that I have to turn off iCloud. I dont't see iCloud anywhere on iTunes or iPhone


How do I reference a table, figure or any other float before it occurs?

I understand that I'll need to compile my document multiple times to update references links. However I compiled it three times and it still can't display references before the actual table occurs. Figure links somehow work, but not tables.  Example  % ... \begin{document}     % ...     \begin{table}[H]         \label{tab:studium_komplet}         \caption{Shrnující údaje doby strávené studiem (úplné údaje)}         \begin{tabular}{ l | c c }             Výhradně legální software          &        Ano &         Ne\\             \hline % ------------------------- | ----------   ------------             Rozsah výběru                      &   \num{38} &   \num{55}\\             Počet chybějících hodnot           &    \num{0} &    \num{0}\\             Minimum                            & \num{0.25} &    \num{0}\\             Dolní kvartil                      &    \num{2} &    \num{1}\\             Medián                             &    \num{3} &    \num{2}\\             Průměr                             & \num{3.97} & \num{3.19}\\             Horní kvartil                      &    \num{5} &    \num{5}\\             Maximum                            &   \num{14} &   \num{22}\\             Směrodatná odchylka                & \num{3.31} & \num{3.35}\\             Variační koeficient~(\%)           & \num{83.3} &  \num{105}\\             Standardní šikmost~(\textendash)   & \num{1.36} & \num{3.41}\\             Standardní špičatost~(\textendash) & \num{1.29} & \num{16.8}         \end{tabular}     \end{table}     % ... \end{document}   I have this table. I need to reference it before it occurs. But this is how it looks like:   How can I reference tables before they occur? Please note, I am using cleveref package.


Check out a single file from a repository using SVNKit

Is it possible to check out a single file from an SVN repository using ?  I have code to checkout a complete directory. But I need only a specific file to be checked out.


So, the question that's always been bugging me is:   What is the proper usage of "This" and "That", not when it comes to objects or things, but when it comes to concepts.  For example, there's a paragraph that goes in a way that's similar to this:      "Coconuts kill a small number of people every year, yet wars have consumed many more lives than coconuts during the long period of human   existence.      That/This fact will not change anytime soon."   Another, simpler example,  is:      "Who is That/This friend you're supposed to meet?"   The basic difference between That/This is that "This" refers to a thing which is nearby, and "That" to a thing which is farther away.   So, how do you use the two words when it touches such vague examples? Does it even matter? Or maybe it would have been This when the statement is inside the same paragraph, and That when it's in another?


Adding zeroes to date for numbers less than 10

I am trying to add zeroes to a date if the day/month is less than 10.  For example, if 2/12/200 is entered, convert it to 02/12/2000.  userDate = input("What is the date? Please enter in MM/DD/YYYY format")  newDate = '' newDate = userDate[3:5]+ "."+userDate[0:2]+"."+ userDate[6:] print (newDate)


Submitted conference paper with errors a short while back. How do I solve this?

BACKGROUND I'm an electrical engineering graduate student.  I submitted and abstract to a conference and it was accepted.  This happened about 3-4 months ago.  Since then, I have mainly focused on other unrelated work.    CURRENT The paper deadline approached and I submitted the paper.  About 10 days later, I realized there were a few errors.  These errors include plots which were left in the paper that I intended to replace with updated accurate plots.   So I submitted the paper with errors.    QUESTIONS What do you recommend I do? Will this negatively effect my reputation with the conference?  How big of a problem is this?  My advisor was not happy with me for barely submitting this on time - so this mistake further complicates my problems.    Thanks


Saving player's progress in a Unity game

I am making a game using the Unity game engine. I want to save the player's progress including level, experience points, chosen character, etc. Presently I am using playerprefs but I want to know whether this will work for gamers who will run this game on their mobile devices (Android/iOS) as well as desktops (OSX/PCs)? If not, then how should I save this information? I want to auto-save player progress after clearing each stage.


This is a simple question concerning undefined articles usage. I have a doubt if the an should be used when the next word to it starts with vowel, or it is related to the noun.  I though it was related the the following word, if I used an adjective as the sentence:   undefined article old man   would be:   an old man  not:  a old man  But I saw in this  that the author writes: An RE (which means Regular Expression) what made question it.  How the an and a usage works?


Command for the table Ruffini-Horner algorithm

I am trying to code a command in LaTeX to type the . You can see in the Wikipedia link above that these are rather simple tables. There is a vertical line at the beginning, after the first column, and there is a horizontal line at the end, before the last row.   I would like to have a command that I can pass the numerical entries of the table and ir draw the rest.   How to do this?  I would like something like \ruffini{...} and in entries we either enter the list of numbers, perhaps separated by commas. Or maybe even entering the numbers with the separators & and \\ to format in what position the go in the table. But I wouldn't want to be thinking about the lines in the table. I would like the command to take care of the line.


Is it possible to on/off a specific USB port using the terminal in Ubuntu?  lsusb displays the following result:  Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 003: ID 2232:1020 Bus 002 Device 009: ID 0bc2:a013 Seagate RSS LLC Bus 002 Device 003: ID 0a5c:219c Broadcom Corp.    is my external hard disk drive. Can I power it off in the terminal?  I tried . But I am confused about what should be replaced in place of usbX.


TV series about armored / mech-driving men

When I was a kid, I used to watch a series that I really liked, but I can't remember much about it anymore. The key parts I do remember:   I saw it in the mid 90's on Dutch television. It was an American series, but I don't know when it aired originally and if the Dutch airing was in synch. It featured a team of four or five men, wearing some sort of modular armor. Their armor was brightly colored, there was a green dude, an orange dude ... The armor allowed them to connect into vehicles; I can clearly remember a motorcycle with side-mounted cannons. I believe one of them had an airplane-rig. I'm a bit unsure about the setting. Definitely futuristic and sci-fi.   Any idea what series this was?


Calculating latitude and longitude of points using QGIS

How do I easily calculate the lat/long of points using the QGIS Field Calculator? I saw a previous related question (), but it deals with a more advanced approach. In ArcGIS Desktop this is similar to the Calculate Geometry function; I just can't find where do this in QGIS.


What does phase velocity physically represent, and why can it be superluminal?

Phase velocity is defined as $v_p=\frac{\omega}{k}$ and is described in various textbooks as being the speed at which the phase of a wave propagates. If you have a wave train that is modulated by an envelope, then while the group velocity gives you the speed of the envelope the phase velocity gives you the speed of the wave within the envelope.  Do $v_p$ and $v_g$ have any meaning if we are only considering one sinusoidal wave and not a superposition of such waves? I have been told that the speed of a single sinusoidal wave is its phase velocity, and that phase velocity is what we're really referring to when we talk about a wave's speed.   However, how can phase velocity be greater than light if this is the case? The standard response seems to be that the group velocity is what determines the rate of information transfer, and it is this velocity that cannot exceed $c$. However, in special relativity a simple limit is set on the speed of any particle, and photons must travel only at speed $c$. If $v_p>c$ then does this not mean that the physical wave within the envelope is superluminal, and so the photons that comprise it are also superluminal?


Prove that ${\sqrt {n} }^{\sqrt {n+1}} > {\sqrt {n+1}}^{\sqrt {n}};n=7,8,9...$ SOURCE : "Inequalities proposed in CRUX Mathematicorum"  I tried induction, but could not prove it. Can anybody provide a hint ?


I have a test.sh script  #!/bin/sh php /home/v/file.php sh /root/x/some.sh   when I execute the file as root from command line it works.  sh /home/v/test.sh    when I set it to crontab -e (is the root cron), is not working   * * * * * sh /home/v/test.sh   What do I do wrong? Thanks


iptables connection limit does not work on debian

I'm trying to set up some basic DOS protection. The following iptables rule works on a CentOS box but NOT on debian (wheezy).   #limit the parallel http requests to 50 per class C sized network     iptables  -A INPUT -p tcp --syn --dport 80 -m connlimit --connlimit-above 50 --connlimit-mask 24 -j REJECT --reject-with tcp-reset   I'm using the GoldenEye DOS tool (among others), and in the CentOS connections are successfully denied, however in the debian box nothing happens (CPU goes up to 100%, apache becomes unresponsive)  Any idea of what might be happening? The rule is succesfully added to the IPTABLES rule list  root@bedrock ~ # iptables -L | grep httpflags REJECT     tcp  --  anywhere             anywhere             tcp dpt:httpflags: FIN,SYN,RST,ACK/SYN #conn src/24 > 50 reject-with tcp-reset  root@bedrock ~ # cat /etc/*-release PRETTY_NAME="Debian GNU/Linux 7 (wheezy)" NAME="Debian GNU/Linux" VERSION_ID="7" VERSION="7 (wheezy)" ID=debian ANSI_COLOR="1;31" HOME_URL="http://www.debian.org/" SUPPORT_URL="http://www.debian.org/support/" BUG_REPORT_URL="http://bugs.debian.org/"  root@bedrock ~ # lsmod | grep ip xt_multiport           12548  12 ipt_REJECT             12502  3 ipt_LOG                12605  8 iptable_mangle         12536  0 iptable_nat            12928  0 nf_nat                 18242  1 iptable_nat nf_conntrack_ipv4      14078  16 nf_nat,iptable_nat nf_defrag_ipv4         12483  1 nf_conntrack_ipv4 nf_conntrack           52720  5 nf_conntrack_ipv4,nf_nat,iptable_nat,xt_state,xt_connlimit ip6table_filter        12540  0 ip6_tables             22175  1 ip6table_filter iptable_filter         12536  1 ip_tables              22042  3 iptable_filter,iptable_nat,iptable_mangle x_tables               19118  14 ip_tables,iptable_filter,ip6_tables,ip6table_filter,iptable_nat,iptable_mangle,xt_tcpudp,xt_state,xt_limit,ipt_LOG,ipt_REJECT,xt_multiport,xt_recent,xt_connlimit


Exact relationship between electric field and intensity

I often see $I(t)\propto |E(t)|^2$. What is the exact form ? Which constants are missing to make this an equality and why are they so often omitted ?


Mac App Store: Downloads just don't start (Mojave)

I want to download apps in the Mac App Store and the apps won't start to download. As you can see in the pictures below, the spinner starts spinning but nothing gets downloaded, the download simply doesn't start. I am logged in with my account. I tried logging out of the App Store and logging in again, restarting the Mac etc, nothing helped.  This is a relatively fresh installation of Mojave 10.14. Before with High Sierra 10.13 everything worked fine. It's a Late 2013 MacBook Pro 13". Installations are allowed from App Store and identified developers.   Some screenshots from Console output below.


Prove that $\lim\limits_{n \rightarrow \infty}\frac{x^n}{n!} = 0$

So I have to prove 2 things:   That $\lim\limits_{n \rightarrow \infty}\frac{x^n}{n!} = 0$ where $n \in \mathbb N$ and $x \in \mathbb R, x>0$.  That $\lim\limits_{n \rightarrow \infty}\frac{x^n}{n!} = 0$ where $n \in \mathbb N$ and $x \in \mathbb R$.    For #1, I know that $\frac{x^n}{n!} >0$, which means that I can find an upper bound and use squeeze theorem. For #2, I have no idea where to start.


transfer windows retail licence to a new computer when the old computer dies and i can not run `slmgr` command to deactivate licence on old computer

Can I transfer windows retail licence to a new computer when the old computer having digital licence dies and i can not run slmgr puk command to deactivate licence on old computer which is dead. Edit I have purchased full package retail product key from amazon with installation media


JAR File Fails - Maven & Hibernate Project

I have an app that do simple CRUDs ops (Create, read, update, delete with MySQL). This app is with maven & hibernate. Everything is fine when I debug and execute the app into the IDE (eclipse).  But I need to create a jar of this app, I tried and when I execute the new .jar file looks that everything is ok.   The real problem is when I execute any action for example insert a new record. I fill the textfields and click into the button to save... but DON'T DO NOTHING!  The app only display the GUI but don't do nothing, don't save, don't update don't delete.  What is wrong? exist any special guide to create a .jar file with hibernate? What should do?  ---------------Update-------------  Well I did many thing I created the .jar file with the shell and looks ok I create the manifest and is ok but is the same problem when I launch the .jar from shell show me this:     Could not initialize the database.  java.lang.ClassNotFoundException:   com.mysql.jdbc.Driver   Looks like the jar cannot found the classpath to mysqulconnector.jar... but is weird because I declare it in the manifest "Class-Path: connector.jar" I dont know how do it.  What should do "attach" or declare the jar to connect to db?


How to cleanup a virus from a pen drive using ubuntu and recovering hidden files

How do l recover hidden files on a pen drive,infected by a virus, as well as cleaning up the virus using ubuntu operating system


Add click event on dynamically created select

I made this example code:   The question is about this click event:  var wrapper = $(".select-editable"); // Fields wrapper  $(wrapper).on('keypress', '#input1', function () {   var cs = $(this).val().length+1;   console.log( "total caracters:" + cs);   $('#mytext1').html('<option value="dummy01">dummy01</option><option value="dummy02">dummy02</option><option value="dummy03">dummy03</option>') });   I use #input1, #mytext1, and I want the click to be dynamic.  For example: if I create four selects in the table, the fourth select should have the click event like the first select (#input4 and #mytext4).  Is it possible?


In a noetherian integral domain every non invertible element is a product of irreducible elements

I want to prove that in a noetherian ring $R$ which is also an integral domain, every non invertible element can be expressed as product of irreducible elements.   I really do not know where to start. Can someone give me hint how to prove this?