How to install xsane on ubuntu 18.04 LTS?

I recently know that there is software viz. SANE [Scanner Access Now Easy] which can automatically detect printer (almost all the printer) and one can easily scan via this software. So I search for that and find a page  and from this page, I get a command to install SANE. The command is      sudo apt-get install sane sane-utils libsane-extras xsane   But while running this command in the terminal, it gives some errors and installation is not done.  The error message is shown in the picture.  Can anyone tell me how to solve it.


A classical brain teaser is :     You have twelve balls identical in size and appearance but one ball is an odd weight (could be either light or heavy). You have a set of balance scales. How many steps are necessary to identify the odd ball and to say whether it is light or heavy?   The answer is $3$ steps, and the the solution is easily found on the web. But what if twelve is replaced by any number $N > 2$? Is there a general way to find the optimal number of steps?


Confusion in linking concept in compiler

My question is regarding preprocessor and linking phase confusion in compilers (typically c++ compilers).   From the online sources, its said that the compiler doesnt look at other source codes until the linking phase. But during the preprocessor phase of compiler, its said that all the include statements are replaced with their respective source code. Isnt other source files accessed during this phase then? Also, its said during linking phase, the functions of libs are linked. But all functions used in the code from libs are in the include statement and hence are already in the source code itself...right?    Please let me know what I am missing.


Hello I am new to D3 and I am wondering what the best choices would be as to followers. Should I be changing them constantly depending on the situation? Should I be changing them depending on the difficulty, or the class? What is the best way to determine what follower I should be using. I am currently using the new Crusader class. Help me out here becasue my indecision is through the roof.


I am not getting whole idea behind Public Key Encryption technique.  As according to fact, public key encryption method uses two keys a public key known to everyone private key known only to recipient of the message  For an instance let assume, John wants to send a secure message to Jane, He uses Jane's public key to encrypt the message. Jane then uses her private key to decrypt it.  The thing i am not getting is, as far as i know if we want to encrypt any message using a key, from that same key only we can decrypt that particular message.  But in public key encryption case both keys are different than how it is possible to decrypt the message.  Please clarify my issue and guide me through if i am going anywhere wrong in understanding the whole concept


How do I count the number of nodes in a View

I would like to display the number of nodes in a particular view OUTSIDE OF THAT VIEW. For example, on the home page (page--front.tpl.php) I want to insert a simple php echo statement that pulls the number of nodes in "View X", and another php echo statement that pulls the number of nodes from "View Y", etc.  function theme_get_node_count($content_type) {      $query = "SELECT COUNT(*) amount FROM {node} n ".               "WHERE n.type = :type";      $result = db_query($query, array(':type' => $content_type))->fetch();      return $result->amount; }   The previous code does not work because I am not counting a content type. Is there a $view variable I can plugin into this function to achieve the same results?  Thanks


Using jq within pipe chain produces no output

The issue of jq needing an explicit filter when the output is redirected is discussed all over the web. But I'm unable to redirect output if jq is part of a pipe chain, even when an explicit filter is in use.  Consider:  touch in.txt tail -f in.txt | jq '.f1' # in a different terminal: echo '{"f1":1,"f2":2}' >> in.txt echo '{"f1":3,"f2":2}' >> in.txt   As expected, the output in the original terminal from the jq command is:  1 3   But if I add any sort of redirection or piping to the end of the jq command, the output goes silent:  rm in.txt touch in.txt tail -f in.txt | jq '.f1' | tee out.txt # in a different terminal: echo '{"f1":1,"f2":2}' >> in.txt echo '{"f1":3,"f2":2}' >> in.txt   No output appears in the first terminal and out.txt is empty.  I've tried hundreds of variations but it's an elusive issue. The only , as discovered through mosquitto_sub and The Things Network (which was where I also discovered the issue), is to wrap the tail and jq functions in a shell script:  #!/bin/bash tail -f $1 | while IFS='' read line; do echo $line | jq '.f1' done   Then:  ./tail_and_jq.sh | tee out.txt # in a different terminal: echo '{"f1":1,"f2":2}' >> in.txt echo '{"f1":3,"f2":2}' >> in.txt   And sure enough, the output appears:  1 3   This is with the latest jq installed via Homebrew:  $ echo $SHELL /bin/bash $ jq --version jq-1.5 $ brew install jq Warning: jq 1.5_3 is already installed and up-to-date   Is this a (largely undocumented) bug in jq or with my understanding of pipe chains?


Prove that $2^q+q^2$ is divisible by 3 where $q$ is a prime and $q\geq5$.

I'm looking to prove that $2^q+q^2$ is divisible by $3$ where $q$ is a prime such that $q\geq5$.  I know that primes greater than five will be congruent to either $1\ (\text{mod}\ 3)$ or $2\ (\text{mod}\ 3)$, which means that the $q^2$-term will always be congruent to $1\ (\text{mod}\ 3)$ which simplifies the problem to finding the congruence of $2^q+1\ (\text{mod}\ 3)$. However, I'm unable to go any further as I'm unable to show that the congruence of $2^q\ (\text{mod}\ 3)$ is always equal to $2$.


Rotating Chart symbols with ArcMap dataframe?

I am using ArcMap 10.2 and want to represent a layer in a rotated dataframe with chart (graph) symbology. The problem is that the charts do not rotate with the dataframe:     I thought I could convert to graphics and rotate each chart individually, but   that is very tedious I don't find an option to convert a layer to graphics, works for the legend but not for the actual layer symbology


What is the maximum wattage LED bulb that can be used in a 75 watt fixture?

What is the absolute maximum wattage LED bulb that can be used in a fixture rated for 75 watt incandescent bulbs?


Prove that if one of the numbers $(2^n)-1$, $(2^n)+1$ is prime, then the other is composite.

Let n be an integer greater than 1. Prove that if one of the numbers $$2^n-1, 2^n+1$$ is prime, then other is composite.


Confused with the real meaning of "QUITE"

I've been using the word 'quite' for a long time now. And I just learned its other meaning. Based on Google/Dictionary:  to the utmost or most absolute extent or degree; absolutely; completely. "it's quite out of the question"  to a certain or fairly significant extent or degree; fairly. "it's quite warm outside"    I guess the question is: how would you know which of these two different meanings is used in a sentence (both in written or verbal)? For instance, I was asked how's the exam. I would like to answer "It was a bit hard". Now if I use the word quite: The exam was quite hard!, how would the other person know if I mean: a. "it is absolutely hard!" or b. "it is not so hard"?


I am trying to decode the string bellow:  st='arroz e feij\xc3o, bife ao molho de tomate, pts com quiabo\r\nSALADA: alface, r\xdacula, rabanete e cebola\r\nSOBREMESA: ma\xc7\xc3\r\nSUCO: Amarelo 3\r\n o card\xc1pio cont\xc9m gl\xdaten no p\xc3o. n\xc3o cont\xc9m ovos e lactose. traga sua caneca!'   Using:  st.decode(?)   But I don't now the correct codec.


.  It would be nice to have the option to just upload an avatar rather than have to use some external service like gravatar.  While gravatar may be convenient and useful, it's also a serious privacy concern because the operators of gravatar have basically got a web bug that allows them to track users and identities across multiple sites.  ISP proxy servers can do similar tracking, associating their own users with gravatars and logins on various sites just by analysing the proxy logs... as can corporate and other proxy servers.  Lots of people don't have a problem with that, but I do.  So I refuse to use gravatar and similar services.  (I'm not terribly happy about OpenID for the same reason — but at least I can set up my own OpenID server if I want to... which is what I'm going to do when I can be bothered.)


Determine the calling context in a trigger

In Apex that is running in the context of an external API call (in my case, via the REST API - but same would apply for SOAP), is it possible to determine the 'client' value supplied in the Sforce-Call-Options header? For example, in an Apex trigger that has fired due to an incoming REST API call inserting/updating objects is there any means via which the Apex code can access that client name? I'm thinking in the same way that you can access contextual information about the Url that triggered some Apex via Url.getCurrentRequestUrl(). I've had a good root around the Apex class reference but am unable to find anything obvious.


Domain Registrar Out of Business - Renewing Domain

About a year ago, I registered a domain name with KalyHost, . It seems to have left me in limbo with how I am now to go about renewing my domain name, which expires in 3 days.   I notice in the who-is information, there the entry Sponsoring Registrar: Key-Systems. Can anyone advise what my next steps need to be? Do I need to contact this sponsoring registrar to transfer my domain to another party? Who actually holds the registration for the domain now?


What's the difference between "if" and "whether"?

Using whether is far more common.  It is certainly more formal.     I would like to know whether it is a true story or fabricated.    But we can use if as well in the same sentence.     I would like to know if it is a true story or fabricated.    So when do we use one or the other?


Mobile site navigation - Burger menu or not?

Can anyone share some stats on the pros and cons of both using a burger menu (standard drop down or pop out) Vs a simplified navigation for mobile.  Examples of great navigation can be found here:     - nice sections for products on mobile  Is there a way of turning this into a poll on here?


How do I change the port that I use to remotely access a Windows (7) computer?


Why they use "own" in this sentence : "who's father own notable history..."

In the movie Tron: Legacy, there's a conversation:  I'm sure it comes as no surprise, who we have to acclaim. The head of our software design team. A man who's father own, uh, notable history with ENCOM, helped make this company, what it is today. Edward Dillinger.  My question is, why they use "own" in this sentence instead of using "owns" or "owned".  Thanks


Moving / offsetting point locations using ArcPy or ModelBuilder?

I have a number non-georeferenced CAD layers (see ) that have text annotation features.  I have created a model to convert the text to points, but after converting the annotation to a Point featureclass, I see that the CAD text anchor points do not coincide with the center of the CAD text (which is where the points belong).    Therefore, I would like to programatically (using ArcPy or ModelBuilder)  using a measured X,Y value that I will provide.  This would allow me to move the GIS points back to where they belong, instead of the offset CAD anchor point.    How can I accomplish this task?    @PolyGeo gave an excellent  using SHAPE@XY IN 10.1, but currently I am running 10.0.  Any 10.0 ideas?


What exactly is a frame of reference in Newtonian mechanics?

I don't understand the concept of a frame of reference. I've read from online sources and they defined it as an abstract coordinate system. What is the coordinate in this system then and how do they all connect to each other? Then I've read the mentioning of an observer and the observer's state of motion and I don't understand how that relates to a frame of reference. I don't understand how these concepts all work together to define a frame of reference. Please help.


I want  a method  for find the number triangles in the under image.


Instantiate a generic class T object and return it

I'm working on java selenium tests and I am trying to setup a fluent/method-chaining design code: I have a generic button class that allows navigating from a page class to the other. Buttons are attributes of my pages classes. Method in the button class should be able to return generic page classes that were defined on button instantiation (the page you are on, the page the button leads to etc.). But I can't figure how to do it without breaking the fluent design in the main class: Button.java public class Button<T, U> {     public T observe() {         return new T(); // Does not work     }      public U click() {         return new U(); // Does not work     } }  FirstPage.java public class FirstPage {     public Button<FirstPage, SecondPage> buttonOnFirstPage = new Button<>(); }  SecondPage.java public class SecondPage {     public Button<SecondPage, AnotherPage> buttonOnSecondPage = new Button<>(); }  And finally what I want to be able to do without casting or mentioning types, in order to benefit from autocompletion and other fancy IDE stuff: BrowsingTest.java public class BrowsingTest {     public static void main(String[] args) {         new FirstPage()             .buttonOnFirstPage.observe()             .buttonOnFirstPage.click()             .buttonOnSecondPage.observe()             .buttonOnSecondPage.click(); //etc.     } }  Any idea on how I can build that button class? Thanks a lot!


What areas of physics depend on the sum $1 + 2 + 3 + 4 + 5 + 6+ 7+\ldots= -1/12$?

This youtube video from Numberphile,   shows how the value is derived. In the video, one interviewee claims that "this result is used in many areas of physics". In the video, only string theory is mentioned.  Which areas of physics use or depend on the sum $$1 + 2 + 3 + 4 + 5 + 6+ 7+\ldots= -1/12?$$


What is 2 layerd circles component in this circuit?

What is the 2 layered circles symbol in this circuit? What does it do?


Alignment issue in the Edit Profile & Settings -> Preferences page

There is an alignment issue in the  page, under the Tags section the Add buttons has extra height.  Screenshot for reference:        The alignment issue is in all the Stack Exchange main and meta sites. Not sure this is due to the impact of the recent .


Drive path not retained in softwear memory after reboot

Question rephrased to better fit my situation at the time of asking:  After rebooting my computer; all memory of recent file use by software programmes accessing files upon my second hard disk, are lost; How can I stop this loss of information?


The generating function of the Fibonacci sequence as a rational function

Prove that if $$f(x)=\sum _1 ^{\infty} a_n \cdot x^n,$$ where $(a_n)$ is the Fibonacci Sequence, and if $|x|<1/2$, then $$(x^2 + x - 1) \cdot f(x) = -x.$$   So far, as an earlier part of this question, I've shown that $a_{k+1}/a_k \le 2$ and that $f(x)$ converges for all $|x|<1/2$.  Although I'm aware that this $f$ converges, I have no method for finding what it converges to!   This question implies that $f(x) = -x/(x^2 +x -1)$ which, for $-1/2 < x < 1/2$ is inside $(-4/10,2)$. I've also tried factoring the $(x^2 + x -1)$ into my series for $f$, but just don't know where to go from here.


I have managed to automatically build an HTML table based on a output from my ERP system, and managed to use CSS to format it easily.  The last step is conditional formatting in a Date Field.  If the date is <  from now make the field RED if it's between 4 <> 7 days from NOW make it YELLOW  else "no formatting.  I have gotten this far on dozens of examples from this site, and I am hoping you can help me do some basic DATE MATH which for some reason I just can't get my head around.    Right now my date field is in  the td:nth-child(4) and I want to compaire it to the current date.      <script>      $(document).ready(function() {              $('table td:nth-child(4)').each(function() {                 var D1 = $(this).text();                 var D2 = new Date();                  if ((D1 - D2) < 4) {                     $(this).css('backgroundColor', 'RED');                  }                 else if((D1 - D2) < 7) && ((D1 - D2) > 4) {                     $(this).css('backgroundColor', 'YELLOW');                  }                 else {                     $(this).css('backgroundColor', '#99faa0');                  }              });             event.preventDefault();     });      </script>


What is the fastest way (general method) to calculate the quantity $a^b \!\mod c$? For example $a=2205$, $b=23$, $c=4891$.


Prove a group generated by two involutions is dihedral

Prove a finite group generated by two involutions is dihedral   Is my following argument correct?  Let $G=\langle x,y\rangle$ be a group generated by involutions $x,y$. Let $n=\mathrm{ord}(xy)$ to get a presentation $G=\langle x,y\mid x^2=y^2=(xy)^n=1\rangle $ so G is dihedral of order $2n$ ?  Further note: I realise now my argument is not sufficient as it remains to show $G$ has no other relations.  I just found an idea from a reference which claims "...So $G$ must have a presentation of the form $G=\langle x,y\mid x^2=y^2=(xy)^m=1\rangle $, then one has to show $m=n$..." in which I do not understand why $G$ has exactly a presentation of such form (the presentation inovlves $m$)? That reference also showed $|\langle x,y\rangle |=2n$ which directly led to the conclusion: $m=n$


Draw cirlcle on Equirectangular projection

I'm trying to draw a circle (actually a great circle) on an equirectangular map to archive something like this  (from ).  So I have the lat/lon coordinates of the center of the circle on the surface of the sphere and I already have the coordinates (the position of the sun) and would like to have a function describing the border of this circle on an equirectangular map by using these coordinates.  I think the answer mentioned above fits my needs, but sadly I don't understand it entirely. Is there an easy way to do this?


Virtual Box Won't Accept .ISO To Install OS

I am trying to install a Virtual Machine, and every time I select the installation media I get this error:  Failed to open the CD/DVD image /home/jesse/Documents/Microsoft Windows Distribution ISO Archive/Microsoft.Windows.XP.Professional.ISO. Could not get the storage format of the medium '/home/jesse/Documents/Microsoft Windows Distribution ISO Archive/Microsoft.Windows.XP.Professional.ISO' (VERR_NOT_SUPPORTED). Result Code: VBOX_E_IPRT_ERROR (0x80BB0005) Component: Medium Interface: IMedium {53f9cc0c-e0fd-40a5-a404-a7a5272082cd} Callee: IVirtualBox {c28be65f-1a8f-43b4-81f1-eb60cb516e66}   I would like too know how to fix this annoying error.


Is a transit visa required for an Indian in a connecting flight via USA coming from Toronto?

I am an Indian studying in Toronto, returning to India via USA in a connecting flight. Do I need a transit visa?


ways to select a non-empty subset of these people, such that no two adjacent people are selected.

I have asked this question before  The first guy solved it in a way, but  i would like to know is there any efficient way to do so, because i did the same for N = 13 and N = 15  which took long time.  This problem is from a pen and paper test, ZIO-2018 Can i solve it with an efficient algorithm, well i am pretty beginner in algos, so if there is one kindly descibe it how can i do so?  Thank you


How do I edit the boot order in the GRUB menu to have Windows first?

I have a dual boot on my computer of Windows 7 and Xubuntu 12.10. The Linux boot is 1st and the Windows 2nd. I would like to reverse the boot order in the GRUB menu. I need to know the steps to go about editing GRUB. I do most of my work on Windows and need it to be 1st so I can boot up and not watch it.


$\sup_{0 \leq M \leq I_{\mathcal{H}_1}} \frac{\operatorname{Tr}[\rho M]}{\operatorname{Tr}[\sigma M]}$ satisfies Data Processing Inequality

$\newcommand{\Tr}{\operatorname{Tr}}$Let $\mathcal{H}_1, \mathcal{H}_2$ be a Hilbert spaces and $\rho, \sigma$ be density matrices on $\mathcal{H}_1$. Define $$D(\rho\parallel\sigma) := \sup_{0 \leq M \leq I_{\mathcal{H}_1}} \frac{\Tr[\rho M]}{\Tr[\sigma M]}.$$ (1) Show that $D$ satisfies the data processing inequality, i.e. for any density matrices $\rho, \sigma$ (positive semi-definite, hermitian, trace = 1) and for any $\mathcal{E} \in \text{CPTP}(\mathcal{H}_1 \rightarrow \mathcal{H}_2)$ (completely positive, trace preserving map) holds $D(\mathcal{E}(\rho) \parallel \mathcal{E}(\sigma)) \leq D(\rho \parallel \sigma)$ (2) Show that $D(\rho\parallel\sigma) = \inf\{c \in\mathbb{R}: ~c \sigma - \rho \geq 0\}$ Sidenote: I posted this question first on physics stack exchange, but was told to repost the question here as it seems to fit better on this SE platform.  My attempts: For (1) we have to show that for any density matrices $\rho, \sigma$ and for any $\mathcal{E} \in \text{CPTP}(\mathcal{H}_1 \rightarrow \mathcal{H}_2)$ holds $D(\mathcal{E}(\rho) \parallel \mathcal{E}(\sigma)) \leq D(\rho \parallel \sigma)$. If the denominator is zero, the DPI is satisfied trivially. So we can assume that the denominator is not zero. For this case, I tried to use the Kraus-decomposition of $\mathcal{E}$ and I tried to use some matrix inequalities to show the statement. My problem was that I couldn't find a suitable inequality for the denominator (in the direction we need). For (2) I tried to prove two inequalities and I think that I found a proof for one direction. Therefore, I considered some arbitrary $c$ such that $c \sigma \geq \rho$ holds. Then we obtain $$\sup_{0 \leq M \leq I_{\mathcal{H}_1}} \frac{\Tr[\rho M]}{\Tr[\sigma M]} \leq \sup_{0 \leq M \leq I_{\mathcal{H}_1}} \frac{c\Tr[\sigma M]}{\Tr[\sigma M]} = \sup_{0 \leq M \leq I_{\mathcal{H}_1}} c = c.$$ This holds for all $c$ as defined above. Therefore, we can take the infimum (with respect to c) on both sides and obtain $$\sup_{0 \leq M \leq I_{\mathcal{H}_1}} \frac{\Tr[\rho M]}{\Tr[\sigma M]} \leq \inf\{c\in \mathbb{R}:~ c \sigma \geq \rho \}.$$ On the first glance, the other direction looked easier, as we can choose $M=I$. But then we end up with $\Tr[s \sigma - \rho] \geq 0$, where we denote the supremum by $s$. And I cannot argue why the same without the trace holds true.  I hope that I am now on the correct platform for asking this question and I am grateful for any hint or help to solve this problem!


Is there any difference between Frequentist and Bayesian on the definition of Likelihood?

Some sources say likelihood function is not conditional probability, some say it is. This is very confusing to me.  According to most sources I have seen, the likelihood of a distribution with parameter $\theta$, should be a product of probability mass functions given $n$ samples of $x_i$:  $$L(\theta) = L(x_1,x_2,...,x_n;\theta) = \prod_{i=1}^n p(x_i;\theta)$$  For example in Logistic Regression, we use an optimization algorithm to maximize the likelihood function (Maximum Likelihood Estimation) to obtain the optimal parameters and therefore the final LR model. Given the $n$ training samples, which we assume to be independent from each other, we want to maximize the product of probabilities (or the joint probability mass functions). This seems quite obvious to me.  According to , "likelihood is not a probability and it is not a conditional probability". It also mentioned, "likelihood is a conditional probability only in Bayesian understanding of likelihood, i.e., if you assume that $\theta$ is a random variable."  I read about the different perspectives of treating a learning problem between frequentist and Bayesian.   According to a source, for Bayesian inference, we have a priori $P(\theta)$, likelihood $P(X|\theta)$, and we want to obtain the posterior $P(\theta|X)$, using Bayesian theorem:  $$P(\theta|X)=\dfrac{P(X|\theta) \times P(\theta)}{P(X)}$$   I'm not familiar with Bayesian Inference. How come $P(X|\theta)$ which is the distribution of the observed data conditional on its parameters, is also termed the likelihood? In , it says sometimes it is written $L(\theta|X)=p(X|\theta)$. What does this mean?  is there a difference between Frequentist and Bayesian's definitions on likelihood??  Thanks.    EDIT:  There are different ways of interpreting Bayes' theorem - Bayesian interpretation and Frequentist interpretation (See: ).


What does $\bar{y}$ with a line over it represent?

I've been asked to complete this chart and have never come across this symbol before, nor can I find anything about it on google:    What does the $\bar{y}$ with the line over it represent? And also, does the the t^2 column just mean square all of the time values for each row?


Cardinality of the set of continuous functions

Prove that the set of continuous functions $f: (0,1) \to (0,1)$ has the same cardinality as the open interval $(0,1)$.  I am not sure exactly how to get started. I have access to Schröder-Bernstein, but don't think there is a good way to use it. I can prove that $(0,1)$ has the same cardinality as $\mathbb{R}$, so it would suffice to show that the set of continuous functions has the same cardinality as $\mathbb{R}$, but I don't know how to " exclude" non-continuous functions. Any help would be appreciated.


Typeset subscript material automatically in upright font shape

As discussed for example here:  subscripts should usually be typeset upright. Is there a possibility to this automatically e.g. inserting something to the document-header? Or, if not possible in LaTeX, is there an option in LyX? Until now I do it like this: Q _ Alt Z R test which is quite slow.


Can anybody advise a good ux design for representing a skill level (novice, competent, proficient, expert) for a professional service (for example, doctor, lawyer, interpreter and etc.) in a marketplace app. And how it can be made more useful for a customer (maybe add some discription because the customer is not aware of difference of the levels)?  Some clarification....  In all fields of man's activity a person passes through skill acquisition - A JOURNEY FROM NOVICE TO EXPERT - begins as a novice...and ends as an expert (if he is lucky). Let's take a dentist. At first, he is the novice and just learns at university…but he can do some simple work - for example, teeth cleaning. Then he can drill and then make a solution to fill a tooth. So at first he gains knowledge and some experience.  But as he is getting mature his knowledge and skills are getting better and better. Hence, his experience consists of tasks (or what he can do) and skill level of each task (or how good he is at). But at each stage of his skill journey he is able to provide his service...even he is a novice doctor he can find his patient or a patient can find him.  So how can we represent these skill levels (novice, competent, proficient and expert) in order to help (1) a customer to understand what this level means to make the right choice (with regard to price/quality) and (2) a service provider to differentiate himself (with regard to price/quality)?


How well does Flashmode work with MacTeX-2018?

I was considering trying Flashmode, an instant-preview add-on for TeXshop:    See also one of the answers here:   However, it seems the Flashmode download page was last updated in 2013:    I'm using the current version of MacTeX (2018), which contains the latest version of TeXShop (4.22), on a Mac running MacOS 10.13.6. How well does Flashmode work with this more current software?  And about how much delay should I expect to see in the updating of the viewer if I'm using a mid-2014 MacBook Pro with the fastest processor option?  I ask because I'm currently evaluating BaKoMa TeX Word, and was wondering if there are any other options I should consider.


How do I stop my rim brakes making a squeaking/squealing sound?

I bought a Schwinn Frontier Sport few months ago and started riding happily. After a few weeks my front rim brakes started creaking. It's so annoying in public places. My rear brake doesn't produce any sound but isn't as powerful as the front brake.  The retailer says cleaning would solve the front brake's issues and I got it cleaned, but nothing changed. Is there something I can do something myself to fix this?


number theory : let $a \in \mathbb Z^+$ find $(a,a+1)$

let $a \in \mathbb Z^+$   find:  1)  $(a,a+1)$     2) $(a,a+2)$  please guide me to solve this question it's about number theory


how to remove or change background fills in all tables in a microsoft word document

I have a bunch of large documents, with many tables that have different and inconsistent fill styles - some of them are not readable in black and white when printed.   I cannot change the background fill for all the tables at once. The problem I have is that when I open such a document, and Select All, the Table Properties are inactive.  Do you know a technique for selecting all the tables, or a method for applying global format of tables, with a script or some other way?


I was changing partition style of my hdd but did that to my sdcard instead that was plugged in the laptop. I havent touched the sdcard now, it still has all the space unallocated. It had very important data that i need to get back. Please advice how should I proceed. Kindly help 😅


Why did life on Earth develop with two sexes?

If evolution gives us the best adapted organisms for survival of the fittest, why does so many of Earth's organisms require two sexes for reproduction?  Shouldn't this have been bred out of our populations millennia ago?


How does time stoppage inside a blackhole affect physics?

From the gravitational time dilation theory we know that at event horizon of a black hole the time should stop completely. However all the physics phenomenon we know (at macro level) e.g laws of motion are based on time so I have following questions bugging me:   Since all matter appears to interact with each other physically (collision, friction etc) over time, these phenomenon would not happen at event horizon and further. Because there is no flow of time so there should not be any motion and things pushing each other or getting heated up due to friction etc because there is no time flow which should lead to absence of events Since there is no time flow the matter being sucked in would not push other matter at event horizon because the time stops there and motion shouldn't happen. This means that all the matter that is being sucked in could actually be a unimaginably thin layer with unimaginable density at the event horizon which never falls in further.    Edit: What's even more mind boggling is the fact is some of these black holes are known to be moving around at millions of kilometres per hour in Earth's time perspective even though their time is stopped.  So how can it move around in zero time? Or is it moving in T→0 time?  Are the above conclusions correct (or do they even make any sense), assuming that a black hole doesn't obey some unknown physics?


How do people know a person is a knight in westeros?

In A Song of Ice and Fire universe, how do people know that a man is a knight? Is there any symbol or proof by which people know someone for a knight? Is there any written proof to prove a person's knighthood?


How to use moveTo?  I do so:  actor.addAction(Actions.moveTo(500, 500, 10));   but he does not move  Thanks you  UPDATE  does not move  my code:  public class MyActions extends ApplicationAdapter {     private Stage stage;     private Actor actor;      @Override     public void create () {          stage = new Stage();         actor = new Actor(){             {                 setSize(100, 100);             }             Sprite actorSprite = new Sprite(new Texture(Gdx.files.internal("badlogic.jpg")), 57, 10, (int)getWidth(), (int)getHeight());              @Override             public void draw(Batch batch, float parentAlpha) {                 actorSprite.draw(batch, parentAlpha);             }         };          stage.addActor(actor);         actor.addAction(Actions.moveTo(500, 500, 1));     }       @Override     public void render () {         Gdx.gl.glClearColor(1, 1, 0, 1);         Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);         actor.act(Gdx.graphics.getDeltaTime());         //stage.act();         stage.draw();     } }   what's wrong?


Is "iPhone is king" grammatically correct?

"iPhone is king" I am referring here to the article being missed. As far as I know that when a noun is used in a singular form, then we should add an article a/an for the first time, if the noun has been mentioned previously then you can add the. However, in some cases (like this case) I see no article in front of the noun even though it's a noun. Is there an exception or what?


Not using the @Override annotation when implementing an abstract method

How come in the first code block of  there is no @Override annotation on run()? - run() is an abstract method:  handler = new Handler();  final Runnable r = new Runnable() {     public void run() {         tv.append("Hello World");         handler.postDelayed(this, 1000);     } };  handler.postDelayed(r, 1000);   Compare this to my Android onCheckedChanged function which is also an abstract method:  currentlocation.setOnCheckedChangeListener(object: RadioGroup.OnCheckedChangeListener{     override fun onCheckedChanged(group: RadioGroup?, checkedId: Int) {      }  })   which has to have the override modifier (note: that's kotlin code but same principles apply).  How come the 2nd the 2nd code block needs to have the override keyword but the first doesn't?


I am on Debian Testing  How do I enable auto-login to i3 instead of GNOME    Update  I followed the answer provide by jasonwryan, but it did not solve the problem  I did  $ update-alternatives --install /usr/bin/x-session-manager x-session-manager /usr/bin/i3 60   Then I did   $ update-alternatives --config x-session-manager  There are 2 choices for the alternative x-session-manager (providing /usr/bin/x-session-manager).    Selection    Path                    Priority   Status ------------------------------------------------------------ * 0            /usr/bin/i3              60        auto mode   1            /usr/bin/gnome-session   50        manual mode   2            /usr/bin/i3              60        manual mode  Press <enter> to keep the current choice[*], or type selection number: 0   As you see when it asked me to <enter> my choice, I chose 0   Then I did a reboot, but it still logged me in GNOME instead of i3.


Why do particles and antiparticles annihilate?

We know that a photon can split into an electron-positron pair and that when an electron and positron come into contact they annihilate and produce a photon. But why does this happen?


So this question is about the BUGS modeling language. So you either know it or have no clue. I'm a newbie to this so it's been driving me mad. I want to define a simple two-state hidden Markov model (HMM) where the emission of each state follows a Normal distribution. I have an array data of Nxl dimension where each row is a subject and column is a continuous variable Time associated with the subject. So in WinBUGS, I would define the model as:   for(i in 1:N) { # for each subject     # Sample the initial observation     Time[i, 1] ~ dnorm(mu[State[1]], tau[State[1]])      for(j in 2:l[i]) { # for each observation         # Sample the observed variables         Time[i, j] ~ dnorm(mu[State[j]], tau[State[j]])         # Sample the hidden states         State[j] ~ dcat(P[State[j-1], ])     } }  # P is the transition matrix of the hidden Markov chain P[1, 1:2] ~ ddirch(Pinit) P[2, 1:2] ~ ddirch(Pinit)  # Set the initial states State[1] ~ dcat(Pinit)  # Sample the initial params mu[1] ~ dnorm(200, 1.0E-6) mu[2] ~ dnorm(400, 1.0E-6)  # The precision params tau[1] ~ dgamma(0.001, 0.001) tau[2] ~ dgamma(0.001, 0.001)   Initial values have also been provided via R2WinBUGS. The model is syntactically correct. But when I run, I got this error: "multiple definitions of node State[2]"  Can you please tell me why and how to solve this? I've searched around on the error but each has their own specific case and there's not a generic solution or explanation as to why this arises.


Moving points between different Stack Exchange sites

I'm a member of several sites.  Some have questions I enjoy answering. Some have questions for work I need answering as I know little about it. Some have questions I answer because I like helping out.  The problem is that my reputation varies from site to site, which is very frustrating.  Could we have the points centralised or at the very least have a mechanism to move points about?  For example to use the points I earned from what I do know about, to put a bounty on what I don't! (Surely that's one of the main reasons for the points system?)


Can we show how many meta reviews there are?

Can we show how many meta reviews there are, like all other review tasks? Just add a number in the blank space on the left.


Behaviour of $L^2$ functions at infinity

Is it possible to prove that if $f\in L^2(\mathbb {R}) $ then $\exists\lim_{x\to\pm\infty}\lvert f\rvert^2$ and $\lim_{x\to\pm\infty}\lvert f\rvert^2=0$? If not, is it easy to find a counterexample?


Let's say I have a custom post type Books, and I tag the books with a custom taxonomy "Person". The taxonomy contains the name of a person and basically means the person has read that particular book.  So, a book can obviously be tagged with multiple "Persons".   I wanna list Books and order them by the number of "Persons" that have read it. Basically, count the number of "Person" tags, and order the Books by that.   I'm reading the documentation on wp_query but don't see a way to do this. Is it doable?


I would like to say: Available calculation methods are limited to few software. With "few", I mean 3 programs. However, "software" is an uncountable noun. "Some" and "little" sound also weird?  Available calculation methods are limited to few software.   Available calculation methods are limited to little software.   Available calculation methods are limited to some software.


execute drush command from devel/php drupal

Can any one please tell me how can I execute drush command from devel/php?  I can execute PHP codes from devel/php. But I don't know how can I execute drush command from devel/php. (As we know "devel/php" URL coming from devel module).  I have written some custom drush command for cron purpose. I can able to run those commands from command line.  > drush my-cmd or drush cc all or drush status , etc ... I can run it through command line.   Expecting some function as mentioned below to run from devel/php  some_function("drush cc all");


In IE 11 the first tag tries to escape the tags box

When writing an question here on meta I noticed the  tries to get away at the left side of the Tags box.    This only happens on IE11 (Win7/x64). I couldn't repro on Chrome or Firefox.  I and others have seen similar issues, , ,  and , across browsers.  If there is time, can this be fixed for those poor IE11 users?


Net acceleration felt by a body on Earth

For any body on earth will the only acceleration it has be gravity or should we take into consideration even centrifugal force due to rotation?  Is there any precise formula to determine the net acceleration?


KeyEvent returns NullPointerException; how do I define e?

I am creating a KeyEvent for my Main class, what I want the event to do is when the UP key is pressed, it will return n as false, and when the DOWN key is pressed, it will return n as true.  package main;  import java.awt.event.KeyEvent;  public class IsStopped {      public static boolean main(String[] args, KeyEvent e) {         boolean n = false;          int key = e.getKeyCode();         if (key == KeyEvent.VK_UP) {             return n = false;         }          if (key == KeyEvent.VK_DOWN) {             return n = true;          }         return n;     } }   I want to use n for my Main class. Like this inside a loop:  if(main.IsStopped.main(args, null) == false) { break;   This is what returns once I run my Main class:     Exception in thread "main" java.lang.NullPointerException   at main.IsStopped.main(IsStopped.java:12)   at main.Main.main(Main.java:27)   How would I define e?


I want to install proxychains from terminal and the code is   apt-get install proxychains   but it said  Could not open lock file /var/lib/dpkg/lock - open (13: Permission denied) E: Unable to lock the administration directory (/var/lib/dpkg/), are you root?   How can I fix this?


VCenter 5.0 Server shows error on Hardware Status for hosts (port 8443)

I have the following:   vCenter 5.0.0 build 755629   The problem:  In the plug-in manager:  vCenter Hardware Status  VMware, Inc. 5.0 Disabled Displays the hardware  status of hosts (CIM  monitoring) The following error occured while downloading the  script plugin from https://192.168.1.1:8443/cim-ui /scriptConfig.xml:  The client could not send a complete request to  the server. (The underlying connection was closed : An unexpected error occurred on a send.)   vCenter Service Status  VMware, Inc. 5.0 Disabled Displays the health status  of vCenter services The following error occured while downloading the  script plugin from https://192.168.1.1:8443/health -ui/scriptConfig.xml:  The client could not send a complete request to  the server. (The underlying connection was closed : An unexpected error occurred on a send.)   What I have tried   Read many article online regarding this matter. Enabled - Secure Socket Tunneling Protocol Service I can access the URLs located above with only http, thus there must be an issue with SSL, I am guessing here.   Side notes:   We have no plans to update to vCenter 5.1 as of yet. I have been looking for 2 days for a solution so far.    Does anyone know of any solution for this please?


How to create debian package for a java project?

I have written a small gui for btrfs called . And export it as .jar file. How do I package it as  a .deb file for Ubuntu?


Two point charges in the vacuum (so ignore all frictions). They have opposite signs so they will move towards each other under Coulomb's force. The magnitude of their charges are $q_1$ and $q_2$ respectively, their distance is $l$, and their masses are $a$ and $b$. They start from a static location before they start traveling towards each other. How long does it take before they collide? I guess one can set up an differential equation for this. We set an equation for conservation of energy, where electric potential is being converted into kinetic energy, and another equation for conservation of momentum, based on the distance two charges have traveled. But the computation is tedious.. Is there an easier solution? It looks like a classical setup that should come with a more elegant solution though.. . [EDIT] I wonder if Kepler's Third Law works since it assumes the force between two entities are proportional to the masses, but not the case here.


Necessary and sufficient condition for the matrix $A = I - 2 x x^t$ to be orthogonal

Let $x$ be a non zeo (column) vector in $\mathbb{R}^n$. What is the necessary and sufficient condition for the matrix $A = I-2xx^t$ to be orthogonal?


I know that the one of the axioms of abelian categories is that the induced morphism $ \text{coker}(\ker f )  \longrightarrow   \ker ( \text{coker} f )  $ for any morphism $ f $ is an isomorphism. Let's call this axiom $ \textit{iso} $.  However, Vakil in his notes (, page 48) mentions axioms (2) and (3). One of my friends remarked that  $$(2) + (3)  \Longleftrightarrow  \textit{iso}  . $$   I have been able to show $ \textit{iso}  \implies (2) + (3)  $ , but how do I show that $  (2) + (3)  \implies  \textit{iso}  $?


Does anyone know Dell Laptops well - most use same hardware.. I can use Latitube 3460 according to the database... Can I use Ubuntu on Dell Vostro 3460?


Proof of Equivalence Relation $R=\{(a,b)\in\Bbb N^2: 5\mid (2a+3b)\}$

Given a set of natural numbers ($\Bbb N$), and the relation $R=\{(a,b)\in\Bbb N^2: 5\mid (2a+3b)\}$. Is $R$ an equivalent relation?   My answer: Yes, because $2a + 3b$ is divisible by $5$, if and only if, $2a + 3b − 5b$ is divisible by $5$.  Is my reasoning right?   If it is not, then how do I prove that this is an equivalent relation?


java code to calculate running time for sorting algorithms

I have a java code that calculate the running time for multiple sorting algorithms such as "Merge sort , Bubble sort and so on ..".  The running time after the first algorithm is not calculated correctly due to branch prediction. So is there anyway to avoid branch prediction to get the correct running time.  Example:Running time for revers sorted array with length 200000 index is as below: Average runtime for Merge Sort in seconds after 10 iteration is : 0.0204354182 Average runtime for Bubble Sort in seconds after 10 iteration is : 1.0596160000000001E-4   As you see the bubble sort running time is not correct, it should be more than the running time for merge sort for such array.  Appreciate your help.


Im writing a paper on norms, we use two bars \|\cdot\| for vector norms and triple bars for matrix norms. The problem is that if I use |||\cdot||| the distances between the bars is different and that bothers me (using \|| is just horrible). I wanted to make a new command but i cant make the distance between the bars small enough to look like the vector norm. This is what I tried:  \newcommand{\norm}[1]{|\hspace{0.05mm}|\hspace{0.05mm}|\hspace{0.05mm}#1\hspace{0.05mm}|\hspace{0.05mm}|\hspace{0.05mm}}   I don't know how to make the distance smaller, maybe there's another command for smaller distances that I'm not familiarized with.   Thanks in advanced :)


error : CS0120 An object reference is required for the non-static field or method or property 'Calculator.opsObj'

namespace DelegatePractise1 {  public delegate int AddDelegate(int x, int y);  class Calculator {     MathOps opsObj = new MathOps();     static void Main(string[] args)     {          AddDelegate addDelInstance = new AddDelegate(opsObj.Add);//getting error here          int sum = addDelInstance(2, 3);         Console.WriteLine("{0} sum", sum);         Console.Read();      } }  public class MathOps {      public int Add(int x, int y)     {         return x + y;     } }   }  when i initialize the object 'opsObj' inside the main then the error doesn't come anymore. Can you explain why do i need to include the object initialization inside the main for this case. I am new to oop concept. Thanks in advance


If $x=\cot6^\circ\cot42^\circ$ and $y=\tan66^\circ\tan78^\circ$, then determine the ratio of $x$ and $y$

If $x=\cot6^\circ\cot42^\circ$ and $y=\tan66^\circ\tan78^\circ$, then A) $2x=y$ B) $x=2y$ C) $x=y$ D) $2x=3y$  I seriously don’t know where to start. I don’t need the complete answer, but a starting statement which would give me the direction to solve it would be helpful. Thanks a lot.


The notification tray icon shows the wrong count:    As a temporary workaround to the annoyance of this I thought I would disable the count. This menu option has no effect at all:    Is this a known defect in the current build of Windows 10 (Version 1803, Build 17134.284)? I can't find anything on Microsoft Connect.


How to search for POSTS containing brackets?

I want to search if anyone has asked anything about [how-to-ask]. I typed \[how-to-ask] (brings me \[how-to-ask]), \[how-to-ask\] (brings me \[how-to-ask]) and [how-to-ask\] (brings a non-existent tag). Does anyone know how to search for such stuffs?


I have visited a lot of Q/A and Forum sites similar to this one. Many of them however had spell check. I don't see it as a must fix for the site; however if an automated engine/plugin could check the spelling of questions and answers, it could be beneficial to the users and outsiders of this site.  People love spelling and grammar more than anything, as long as it makes sense.  For instance, if someone says           My fhate is with you, technology.          My fate is with you, technology.      This may be a crummy example, but one letter can change the way someone looks at a question. Without the fate below it, you would think  he meant to type hate, not fate.   Or how about some grammar and format differences.      I am having an issue and I need it fixed soon.      I AM HAVING AN ISSUE AND I NEED IT FIXED IMMEDIATLEY!   They're little things that won't affect it much. These can change the way people view, the user, the site, the community. People are going to want to figure out answers on a site they can trust. Without spell-check people will think this site is not trustworthy even though it is.   I am not saying you have to, but take it into consideration.  It's your fhate.


How do you make the following look nicer: "text...,etc.)."

Consider the following sentence     There are many different fruits (some are harmful: apple,   mango, etc.).   How do you deal with etc.).? It doesn't look nice at all.


Forcing ArcGIS Desktop to re-read file geodatabase dataset extent?

I have feature class sitting in FGDB. I can add it to map, right click on it in the table of content and pick "Zoom To Layer". This is what I see:    I start editing session, remove most of the features in this feature class, save edits, stop editing. Right click on the layer, "Zoom To Layer". This is what I see:    The only option I have is to close ArcGIS session and start a new one.  Is there a better way to tell ArcGIS to use the true dataset extent?


Over the last 3-4 weeks I have been trying to find a rogue DHCP server on my network but have been stumped! It is offering IP Addresses that do not work with my network, so any device that needs a Dynamic Address is getting one from the Rogue DHCP and then that device stops working. I need help to find and destroy this thing! I think it might be a Trojan of some sort.  My Main Router is the only valid DHCP Server and is 192.168.0.1 which offers a range of 192.160.0.150-199, and I have this configured in my AD as Authorized. This ROGUE DHCP claims to be coming from 192.168.0.20 and offering an IP Address in the range of 10.255.255.* which is messing up EVERYTHING on my network unless I assign a static IP Address to it. 192.168.0.20 does not exist on my network.  My network is a single AD Server on Windows 2008R2, 3 other physical servers (1-2008R2 and 2 2012R2) about 4 Hypervisor VM's, 3 laptops and a Windows 7 box.  I can't ping the rogue 192.160.0.20 IP, and I can't see it in the ARP -A output, so I can't get its MAC address. I'm hoping that someone reading this post has come across this before.


Will iOS 9 automatically install on an iPhone? Or will it give an option to install now or later?  And if I choose later, then will it install aautomatically later, or just not suggest it again?


A uniform continuous function which is not Hölder continuous

Can someone give me an example of a function $f: I\to \mathbb R$ which is uniform continuous but not Hölder continuous (for any $\alpha$)? Here $I$ is an interval. If $I$ is closed and bounded then we are essentially assuming that $f$ is merely continuous.   By saying that $f$ is not Hölder continuous for any $\alpha$, I mean for all $\alpha >0$,   $$\sup_{x,y\in I, x\neq y} \frac{|f(x) - f(y)|}{|x-y|^\alpha} = \infty.$$  That is, I need to find a function $f$ so that for all $\alpha$ and $M>0$, there are $x, y\in I$ so that   $$ \frac{|f(x) - f(y)|}{|x-y|^\alpha} \ge M.$$  I know that $f(x) = x^\alpha$ are $\alpha$-Hölder continuous. Thus, in some sense, I am looking for $f$ which are worst than the functions $x^\alpha$ for all $\alpha >0$.


Does QGIS have an autocomplete polygon option like the one in ArcGIS?

I am trying to do digitizing in QGIS, but I do not see an option that I have seen in ArcGIS - autocomplete polygon. I would like to make two adjacent polygons topologically correct, and can not find such an option in QGIS.


What happens when two cards both modify what I'm allowed to do?

Suppose my opponent has  in play, and I have a . The former says I can only cast spells any time I could cast a sorcery, and the latter says I can cast spells any time I could cast an instant.  In this case, looking it up on Oracle gave me a direct answer in the past rulings: Teferi's ability overrides the Leyline's.  But is this just an arbitrary decision? When cases like this come up, how can I decide which effect wins out without searching for specific rulings on each combination? As a general rule, when something like this happens in play, how should I figure out the result?


How checks the correctness of the downloaded from the repository?

For example, Debian repository uses links without HTTPS: deb http://deb.debian.org/debian buster main deb-src http://deb.debian.org/debian buster main  deb http://deb.debian.org/debian-security/ buster/updates main deb-src http://deb.debian.org/debian-security/ buster/updates main  deb http://deb.debian.org/debian buster-updates main deb-src http://deb.debian.org/debian buster-updates main  How is it checked that loaded data from the repository is correct and have not been replaced? Checksum (SHA256) is transmitted by encrypted compound and is compared with the downloaded data via HTTP from the repository?


Change the way a closed question is marked

For example:   For an MVC architecture, should I prefer Ruby on Rails or PHP [closed] Gmail: What is a jQuery selector for incoming mail senders only? How to work with highly compressed and nested CSS in general? [closed]   Better to convert to   [closed] For an MVC architecture, should I prefer Ruby on Rails or PHP [closed] Gmail: What is a jQuery selector for incoming mail senders only? How to work with highly compressed and nested CSS in general?   I should first read the title and sometimes open the question to understand if the question is closed.  I think the [closed] mark  should be at the beginning of the title, not in the end, where I won't ever be if the title is long.  Also coloring will be a good improvement (via @Shadow Wizard).


Wiring ceiling light from switch that controls outlet

I am trying to add a ceiling light to a switch that currently controls a floor outlet (top plug only).  Coming into the light switch are a ground, a hot and a switched hot.  I have pulled an additional 12/2 wire from the ceiling light into the switch box and was wondering how I could wire it in to control both the outlet as it currently is, as well as the ceiling light.  The wire pulls into the attic are pretty difficult as there is 18" of insulation and plaster, so avoiding another pull to the outlet would be preferable, but I understand you gotta do what you gotta do.


Does Tom Riddle/ Lord Voldemort remember the Chamber of Secrets Incident?

I was rewatching the movies and was wondering if Voldemort remembered his encounter with Harry in the Chamber of Secrets since he makes no mention of it when he gains his body again in Little Hangleton and neither in the upcoming meetings both rivals have throughout the books and movies. So would it make sense that Voldemort wasn't aware that his teenage diary was destroyed by Harry?


Mars attack (probability to destroy $n$ spaceships with $k \cdot n$ missiles)

Suppose Earth has been attacked by $n$ Martian spaceships and suppose that we have $m=k \cdot n$ missiles to release against the $n$ spaceships. The probability to hit and destroy each spaceship by each missile is $p$ (independent from the rest).  What is the probability to destroy all the spaceships if we release all the missiles at the same time but each missile will choose a spaceship at random?


SunStudio C++ compiler pragma to disable warnings?

The STLport bundled with the SunStudio11 generates alot of warnings. I beleive most compilers have a way to disable warnings from certain source files, like this:  Sun C  #pragma error_messages off  #include <header.h> // ...  #pragma error_messages on   gcc  #pragma warning(push, 0)          #include <header.h> // ...  #pragma warning(pop)   How do you do this in the SunStudio C++ compiler? (btw, the sunstudio C pragmas don't work in sunstudio C++)


Show that for a and b non-zero integers and c different from zero, then gcd(ca,bc) = |c|gcd(a,b)

I did:  $$ca = cb * k + r \Leftrightarrow \\ ca - cb*k = r \\ c(a-bk)=r \\ a-bk = r/c \\ a = bk +r/c$$  So, $gcd(a,b) = r/c$  What do I do next?


Why exactly is the verb "to throw" used when an error occurs in the program?

Why don't we use "to generate" or "to get"?  E.g.: "External component has thrown an exception", "JavaScript had just thrown an error straight away", "Instances of Error objects are thrown when runtime errors occur".


Should "Closing this question because I didn't get an answer" posts be flagged as "not an answer"?

While reviewing the 10k queue just now, I noticed that someone has evidently searched for and flagged self-accepted answers like        What is the proper way to handle ? Should they be flagged as "not an answer", or should they be left alone?  On the one hand, these answers obviously make no attempt to answer the question. On the other hand, these answers may imply that "I'm no longer looking for an answer — don't bug me."


Unable to use twitter-api as a tag on Stack Overflow

For some reason I am unable to use  on Stack Overflow. Does anyone know why this happens, and how to fix/get round it? Is it a website error?  To clarify, it allows me to type it in on the tags, but as soon as I save edits or post the question the tag disappears?


Very large odds ratio- binary logistic regression

I have obtained a very large odds ratio and standard error for my interaction term after running a binary logistic regression. My study has 4 conditions and 3 dependant variables, however, 1 of the dependent variables is a categorical and so I was told by my supervisor to conduct a binary regression for that dv separately while conducting a Manova for the other variables. The do is a simple yes or no answer to signing up so a fictional follow up study. I have 52 participants. Overall, 44 participants responded yes and 8 responded no. I am aware that the odds ratio may have been so large because I have a very small number in some of my cells. How would I reports very large odds ratio according to apa guidelines or should I run different analysis? The odds ratio is 6 figures so it is huge! Any help would be appreciated. This is for my undergraduate dissertation.


How can I add reflection to a C++ application?

I'd like to be able to introspect a C++ class for its name, contents (i.e. members and their types) etc. I'm talking native C++ here, not managed C++, which has reflection. I realise C++ supplies some limited information using RTTI. Which additional libraries (or other techniques) could supply this information?


I am trying to find the Laplace Transform of $$\frac{1-\cos(ax)}{x}.$$ I have tried to directly compute the integral and also tried to see if I could use the convolution theorem in some way but both lead nowhere. Any help would be appreciated!


How to find the value of $\sum\limits_{n=0}^\infty r^n \sin(n\theta)$?

Question is to find the value of   $$\sum_{n=0}^\infty r^n \sin(n\theta)\text{ for }r=0.5\text{ and }\theta=\pi/3$$  I don't know any tools which can solve this question.


Word wrap is one of the must-have features in a modern text editor.  How word wrap be handled? What is the best algorithm for word-wrap?  If text is several million lines, how can I make word-wrap very fast?  Why do I need the solution? Because my projects must draw text with various zoom level and simultaneously beautiful appearance.  The running environment is Windows Mobile devices. The maximum 600 MHz speed with very small memory size.  How should I handle line information? Let's assume original data has three lines.  THIS IS LINE 1. THIS IS LINE 2. THIS IS LINE 3.   Afterwards, the break text will be shown like this:  THIS IS LINE 1. THIS IS LINE 2. THIS IS LINE 3.   Should I allocate three lines more? Or any other suggestions?


I want to prove that π(m+1,2m) <= (2m choose m)   When π(m, n) is the set of prime numbers in the interval [m,n].  I tried induction but it doesn't work.   I'm now trying to think of a way to show directly that when computing   (2m choose m) = 2m*(2m-1)...(m+1) / m*(m-1)*...*2*1  the denominator disappears, and all that is left is: π(m+1,2m)*(some more numbers)  Can someone please help me? Thank you


Null pointer Exception while Setting data to the TableView in JavaFX?

When I am setting data to the ObservableList it throwing null pointer exception, I could not understand the problem. anyone please help me to find the solution.  Here is my code:  @FXML private Label label; @FXML private ObservableList<ObservableList> data; @FXML private TableColumn column1; @FXML private TableColumn column2; @FXML private TableView table;  public void initialize(URL url, ResourceBundle rb) {     // TODO     String selectSql = "select first_name,last_name from hr.employees";     try (Connection conn = ConnectDB.getConnection(); Statement stmt = conn.createStatement(); ResultSet rs = stmt.executeQuery(selectSql)) {         System.out.println("Getting Connection....");         while (rs.next()) {             ObservableList<String> temp = FXCollections.observableArrayList();             temp.add(rs.getString(1));             System.out.println("First Name == "+rs.getString(1));             System.out.println("Last Name == "+rs.getString(2));             temp.add(rs.getString(2));             System.out.println("List Value === "+temp);             data.add(temp);             //table.setItems(temp);         }         table.setItems(data);     } catch (Exception e) {         //System.out.println("Error: "+e.getMessage());         Logger.getLogger(FXMLDocumentController.class.getName()).log(Level.SEVERE, null, e);     } }   i am getting error in --->  data.add(temp);


Pressing Enter in comment box unexpectedly submits form

I don't think I'm going any more crazy than normal, but I'm surprised I can't see any other meta mention so far. This started happening recently on at least SO and ubuntu.SE, and occurs in at least IE and Firefox. So I'm guessing it's a deliberate feature not [bug]. But I'm not keen.  It's not standard in any browser for a <textarea> to submit when Enter is pressed; the behaviour to me seems spooky and undesirable. I've already accidentally-commented more than once and had to delete the comment and drag the text back into editing.  (I realise you can't actually have a newline in a comment, but I've often used newlines to separate thoughts I'm editing together into a comment, or maybe bits to overflow into a subsequent comment. I don't really want to have to break out the text editor to get this ability.)  May I have my Enter key back please Sir?


How to add background details when I export my CV to PDF on Careers?

I am new to Careers 2.0 and I want my background details when I export my CV to PDF. How do I do that?  I found a workaround... but as this question is marked as duplicate I am not able to answer it.  I just copy pasted my background details in the description of my last open source project, and I made it as heading, So by just designing little bit it now appears in pdf as I wanted!!!  May be this will help someone until the feature is added by Stack overflow.


natbib: setting max number of authors displayed in the references

How do I limit the maximum number of authors displayed in the references.  Example:  @ARTICLE{2013Natur.495...76P,    author = {{Pietrzy{\'n}ski}, G. and {Graczyk}, D. and {Gieren}, W. and     {Thompson}, I.~B. and {Pilecki}, B. and {Udalski}, A. and {Soszy{\'n}ski}, I. and   {Koz{\l}owski}, S. and {Konorski}, P. and {Suchomska}, K. and   {Bono}, G. and {Moroni}, P.~G.~P. and {Villanova}, S. and {Nardetto}, N. and    {Bresolin}, F. and {Kudritzki}, R.~P. and {Storm}, J. and {Gallenne}, A. and    {Smolec}, R. and {Minniti}, D. and {Kubiak}, M. and {Szyma{\'n}ski}, M.~K. and      {Poleski}, R. and {Wyrzykowski}, {\L}. and {Ulaczyk}, K. and    {Pietrukowicz}, P. and {G{\'o}rski}, M. and {Karczmarek}, P.    },         title = "{An eclipsing-binary distance to the Large Magellanic Cloud accurate to two per cent}",            journal = {\nat}, archivePrefix = "arXiv",             eprint = {1303.2063},           primaryClass = "astro-ph.GA",         year = 2013,         month = mar,    volume = 495,         pages = {76-79},         doi = {10.1038/nature11878},         adsurl = {http://adsabs.harvard.edu/abs/2013Natur.495...76P},          adsnote = {Provided by the SAO/NASA Astrophysics Data System}   Instead all of the authors showing up I would like to have something like:  G. Pietrzynski, et al., An eclipsing-binary distance to the Large Magellanic Cloud accurate to two per cent. Nature, 495:76–79, Mar. 2013. doi: 10.1038/nature11878.   Many thanks!


how do I get named ranges in Google Spreadsheets to be more reliable/current?

I'd like to pull values from a named range into a calculation. I have this function:   function getNamedRange(n){   SpreadsheetApp.getActiveSpreadsheet().getRangeByName(n); }   Seems pretty simple. I have a named range called "budgetItems". It definitely exists and has about 6 values in it. But when I try to pull the values with    var items = getNamedRange("budgetItems"); items.getValues();   it usually says items is null. I've gotten it to work in the past but it seems really flaky. I suspect there is eventual consistency and caching goofing things up here.   I've attached this function (to pull the values from the range) to a menu item. When I run that menu item it takes about 15s to run 5 lines of js -- and then fails. That's... suspicious.


How is it possible for you to be at the centre of the universe wherever you are?

I saw on Richard Hammond Builds A Universe on BBC2 a few days ago that you are always at the center of the universe wherever you are.  Surely this is illogical, because you could never get to the edge of the universe.  If I am in the center, then what about that object 10 meters away. Is that at the centre too? How is this possible?  What if I am driving for example. Does this mean that I am moving the universe while I stay still?  Thanks


$\mathbb{Q}$ dense in $\mathbb{R}$ does also $\mathbb{Q^2}$ dense in $\mathbb{R^2}$?

It is well known that density of Rational numbers in Real numbers a well known result which means that there exist infinity many rational numbers between two arbitrary real numbers , Now I ask simply is  $\mathbb{Q^2}$ also dense in $\mathbb{R^2}$? ?


I would like to be able to copy and paste text in the command line in Bash using the same keyboard bindings that Emacs uses by default (i.e. using C-space for set-mark, M-w to copy text, C-y, M-y to paste it, etc.).  The  says that Bash comes with some of these key bindings set up by default.   For example, yanking (C-y) works by default on my terminal. However, I can't get the set-mark and copy commands to work, and they don't seem to be bound to any keys by default.  Usually, the way a user can define her own key bindings is to add them to .inputrc. So I looked and found the following bash functions in the documentation that I presume can help me define the Emacs-like behavior that I want (i.e. set-mark with C-space and copy with M-w).  copy-region-as-kill ()      Copy the text in the region to the   kill buffer, so it can be yanked right   away. By default, this command is   unbound.   and    set-mark (C-@)      Set the mark to the point. If a   numeric argument is supplied, the mark   is set to that position.   If I understand correctly, the above means that copy-region-as-kill is not bound to any keyboard sequence by default, while set-mark is bound to C-@ by default.   I tried C-@ on my terminal, but I don't think it runs set-mark because I don't see any text highlighted when I move my cursor. In any case, I tried adding  keyboard bindings (M-w and C-) to the functions  copy-region-as-kill and set-mark above in my .inputrc and then reloading it with C-x C-r, but this didn't work. I know that my other entries in .inputrc work because I have other user-defined keybindings defined in it.  Is there anything I am doing wrong? Am I missing anything?


Is there a word that means "to give off an odor" (a non-stinky one)?

Most of the synonyms on  refer to a bad odor.  Is there are word like reek which is used to describe good smells?  Example sentence:     Mary dawdled toward Tom and buried her nose in his school uniform   jacket. Despite being new, it already _ his musky scent.


I have a requirement to send mass emails to certain Users of current day created records daily. I am unable to do that with below code. Getting error : Aggregate query does not support queryMore()  Please let me know a way out of this. Code:  global class Incidentimp implements Database.Batchable<sObject> {  public string query = 'SELECT DM_Lookup_id__c,DM_Lookup_id__r.name FROM Incident__c where createddate<>today                              group by DM_Lookup_id__c,DM_Lookup_id__r.name';  global database.querylocator start(Database.BatchableContext BC) {     return Database.getQueryLocator(query); }  global void execute(Database.BatchableContext BC, Sobject[] scope) {        //Map<Inventory_Wishlist__c, Product2> temp = new Map<Inventory_Wishlist__c, Product2>();    // Set<string> accountIdSet = new Set<string> {};    // Map<string,string> xyz=new Map<string,string>();     EmailTemplate emailTemplate = [select Id, Body  from EmailTemplate where DeveloperName = 'POC_DM'];       for (Incident__c item : (List<Incident__c>)scope) {                            Messaging.SingleEmailMessage email = new Messaging.SingleEmailMessage();                         email.setToAddresses(new String[] {'saikat.neogy@cognizant.com'});                        email.setTemplateId(emailTemplate.Id);                         Messaging.sendEmail(new Messaging.SingleEmailMessage[] {email});                   }               } global void finish(Database.BatchableContext BC) {  }  }


java string.trim() got an unexpected result

Here is the code:  String str="    "; System.out.println("("+str+")"); str=str.trim(); System.out.println(str==null); System.out.println(str==""); System.out.println(str.length()); System.out.println("("+str+")");   and the output is:  (    ) false false 0 ()   What's the return character of Multiple spaces.trim() ? Obviously it can't be null.


Extensions of $\mathbb{Z}$ by $\mathbb{Z}$

Given two groups $G$ and $H$, an extension of $G$ by $H$ is a group $K$ with a normal subgroup $N$ isomorphic to $H$ such that the quotient group $K/N$ is isomorphic to $G$ (equivalently, $1 \to H \to K \to G \to 1$ is an exact sequence). So, up to isomorphism, how many (not necessarily abelian) extensions of $\mathbb{Z}$ by $\mathbb{Z}$ are there? One obvious extension is the direct product $\mathbb{Z} \times \mathbb{Z}$. Another extension is the group with the same underlying set as $\mathbb{Z} \times \mathbb{Z}$ and $(a,b) \ast (c,d)$ still defined to be $(a+c,b+d)$ if $b$ is even, but it is defined to be $(a-c,b+d)$ if $b$ is odd (or simply, $(a+(-1)^bc,b+d)$). This nontrival extension is the semidirect product $\mathbb{Z} \rtimes \mathbb{Z}$ corresponding to the homomorphism $\mathbb{Z} \to \operatorname{Aut}(\mathbb{Z})$ where even integers act as the identity and odd integers act as negation. The answer would be $2$ if the direct product and the even/odd semidirect product were the only extensions up to isomorphism. Is this in fact the case?


Why accelerating charged particles radiate EM waves?

Why do they do it?   If I apply some constant force on a charged particle, would it gain velocity just like any other particle or would it lose its energy by emitting radiation?  What if I observe a charged particle from an accelerating frame, would the particle still radiate energy? If so, where does that energy come from ?   Please explain clearly about how the velocity of an electron increases when a constant force is applied.  Not a duplicate of  because my questions are not answered there.


Adding items elements to separate dimensions in a list

New to Python and am having a problem with getting items into individual elements of a list.  I am walking through a subdirectory list and want to write each subdirectory to a separate dimension on a list. So my output would be:  [['roll_274_oe_2014-09-26', ['roll_275_oe_2014-10-03'], ['roll_276_oe_2014-10-10'], ['roll_277_oe_2014-10-17']]   but instead it looks like I'm iterating through the directory tree the number of times I have the output:  [['roll_274_oe_2014-09-26', 'roll_275_oe_2014-10-03', 'roll_276_oe_2014-10-10', 'roll_277_oe_2014-10-17'], [], [], [], []]   my code to do this is at present:  d = 'C:/winPython/WinPython-64bit-3.3.5.5/scripts/portofolio/'       s1 = []  for path, subdirs, files in os.walk(d):      s1.append(subdirs)       print(s1)    I hope someone can give me a hand.  Many thanks


Is there a c like 'Exp1 ? Exp2 : Exp3' in Python?

i would like to know if there is an adequate python alternative for my beloved C Makro 'Exp1 ? Exp2 : Exp3'.  I already tried to google but can't seem to find anything.   Example:  x = 0.5 (x > 0) ? 1 : 0    if(type == "release"):         release = True else:         release = False


Fluctuations in the value of a quantum field at a point?

Suppose there’s a scalar field that permeates the universe.  Do quantum fluctuations really cause the field value ϕ to fluctuate, making the field value higher at some points in space and lower at some other points in space?  Some scientists argued that the quantum field is not fluctuating. The value of a field at a point is not precisely determined but it has nothing to do with fluctuations. $~$While some states that the value of a field at a point in space is constantly fluctuating.


How to use host names rather than ip addresses on home network?

I've a small home network up and running and managed to set up ssh. Can anyone tell me what I need to do to refer to one computer on the network from another by host name rather than IP address (which is what I'm doing now)?


My girlfriend bought a laptop last week. It's a core 2 duo with 4 GB  We installed vista 64bit, and one of the first things we did was right click on "My computer" to see gthe properties. Immediately we noticed something strange about her RAM, the line said: Installed memory (RAM): 4,00 GB (3,68 GB usable)  I told her not to worry, thinking it must be something about the laptop hardware (considering her vista installation came from the same DVD as mine, and I never noticed anything like that on my 4 GB desktop). One hour ago, it got worse. We looked at Properties again, and it now says: Installed memory (RAM): 4,00 GB (2,98 GB usable)  What does that mean? Are those 1,02 GB missing or being used by the system?  EDIT: There is a possibility that the sytem information is wrong. I just noticed that it reports an intel T6500 processor, when it's actually a T6400.  How can I find out how much RAM is really available to the system?  EDIT2: Checking the resource monitors, it says 1003 MB are reserved for the hardware. Is that good or bad? Thanks


The intent of this command sequence is to loop through the 3 options and display either the book/page or instrument no. for each. A excternal programatic function will validate that there is either a book/page of Instrument for each option. I still do not have a feel for how to effective use the available commands but if I can get this going I can build from here.  \newcommand\ErDeedABookA {} \newcommand\ErDeedAPageA {} \newcommand\ErDeedAInstA {I113} \newcommand\ErDeedBBookB {B211} \newcommand\ErDeedBPageB {P212} \newcommand\ErDeedBInstB {} \newcommand\ErDeedCBookC {} \newcommand\ErDeedCPageC {} \newcommand\ErDeedCInstC {I313}  \newcommand\LP {A} \newcommand\Er[1]{ErDeed#1Book#1} \newcommand\AB {\csname\Er\LP\endcsname}  \newcounter{zz} \setcounter{zz}{1} \renewcommand\thezz{\Alph{zz}} \renewcommand\LP {\thezz} \newcommand\EBI {} \newcommand\EBB {} \newcommand\EBP {}  \whiledo {\value{zz} < 4}% {% \ifcsempty {\AB} {\renewcommand\Er[1]{ErDeed#1Inst#1}\renewcommand\EBI {\csname\Er\LP\endcsname} Instrument No. \EBI} {\renewcommand\Er[1]{ErDeed#1Book#1}\renewcommand\EBB {\csname\Er\LP\endcsname} Deed Book \EBB,  \renewcommand\Er[1]{ErDeed#1Page#1}\renewcommand\EBP {\csname\Er\LP\endcsname} Page \EBP}    \stepcounter {zz}% }


Using induction for $x^n - 1$ is divisible by $x - 1$

Prove using induction that for all non-negative integers n and for all integers $ x > 1 $, $ x^n - 1 $ is divisible by $ x - 1 $.  Step 1: We will prove this using induction on n. Step 2: Assume the claim is true when $ n = 1 $. $$ x^{n+1} - 1 = x(x^n - 1) + (x - 1) $$  Can someone help me with this further?


Trying to get all this terminology straight in logic

Really confused on the terminology here.  According to a few resources as-linked:   is defined as a logical form where it is impossible to have true premises leading to a false conclusion. It doesn't mean the premises are necessarily true. Just that if they were true, the conclusion would need to be true as well.   is defined as a valid logical form where the premises are indeed true.  But then we also have "" denoted $\Gamma \vDash \varphi$ which normally means "if everything on the lefthand side is true, then the stuff on the righthand side is true." Sometimes this is also referred to as "validity" or "tautology."  But this also seems like it is clashing with the definition of "sound" as well.  So I'm really quite confused how we're supposed to be defining and separating these terms out. I'm seeing different  on , different answers in ,   in other Math StackExchange posts, etc.  I'm going nuts over here trying to separate all these concepts (metalogic vs. logic, soundness vs. validity, semantic vs. syntactic, etc) when every other resource is constantly merging stuff together in vague ways.  Once and for all what is the definition of validity? Soundness? Completeness? Syntactic consequence? Semantic consequence? Logical consequence? Tautology? Theorem? Axiom? Inference? Formula? Sentence? Expression? Proposition? Statement? Relation? Connective? Operator? Are any of these actually synonyms of each other? How are they different?


Short story: man stranded on Mars, hears clacking sound

I would like to recall the name of a story I read long back, it goes like:  On a Martian mission a man gets stranded somewhat far from the base as his vehicle breaks down. He decides to walk back he goes along a canyon, as he passes a particular spot (noted earlier in the story for its geographical features of containing polished stones or some such things) he hears a clacking sound.


In Ubuntu 18.04, my current desktop looks like this:    How do I display date under time in GNOME panel as below?


When proving $S$ is a subring, why do we prove that S is closed under subtraction not addition?

I see that the definition of a subring requires that a subring should be closed under subtraction. But what I learned was that to be a subring, it should be closed under addition and multiplication. Where does that subtraction come from? Does it have something to do with inverse?


Let $T: V \rightarrow W $ be an injective linear transformation, where $V, W$ are vector spaces of dimension $n$ over the field $\mathbb{K}$. If $\{ e_1, ..., e_n\}$ is a basis for $V$, show that $\{T(e_1), ..., T(e_n)\}$ is a basis for $W$.  What I'm thinking is the solution:  Since $T$ is an injective function, that means no two $v \in V$ will map to the same $w \in W$. Hence, each $ t \in \{T(e_1), ..., T(e_n)\}$ is distinct to each other. As $V$ is linearly independent, then all $t$ are linearly independent to each other as well, which forms the basis of $W$.


Could you walk me through the most efficient way to solve this modulo?     $276^{247} \mod 323$


How to use \hyperref to change font color of citation?

When I use hyperref with natbib, it creates a boxed link to my bibliography. Is there any way to not create the box but show the cited paper with a different color instead. For example,


Chromium wont install ubuntu 16.0.4 LTS 32bit

Whenever I try install chrome, it throw me an error:  $ sudo apt-get install google-chrome-stable E: unable to locate package google-chrome-stable   I was running this command before:  echo "deb http://dl.google.com/linux/chrome/deb/ stable main" | sudo tee /etc/apt/sources.list.d/google-chrome.list  wget -q -O - https://dl.google.com/linux/linux_signing_key.pub | sudo apt-key add -   sudo apt-get update   sudo apt-get install google-chrome-stable   Using the software center just leads to a frozen download bar in the dashboard.


Using proof by contradiction vs proof of the contrapositive

What is the difference between a "proof by contradiction" and "proving the contrapositive"? Intuitive, it feels like doing the exact same thing. And when I compare an exercise, one person proves by contradiction, and the other proves the contrapositive, the proofs look almost exactly the same.  For example, say I want to prove: $P \implies Q$ When I want to prove by contradiction, I would say assume this is not true. Assume $Q$ is not true, and $P$ is true. Blabla, but this implies $P$ is not true, which is a contradiction.  When I want to prove the contrapositive, I say. Assume $Q$ is not true. Blabla, this implies $P$ is not true.  The only difference in the proof is that I assume $P$ is true in the beginning, when I want to prove by contradiction. But this feels almost redundant, as in the end I always get that this is not true. The only other way that I could get a contradiction is by proving that $Q$ is true. But this would be the exact same things as a direct proof.   Can somebody enlighten me a little bit here ? For example: Are there proofs that can be proven by contradiction but not proven by proving the contrapositve?


What does “{} \;” mean in find (in Linux)?

Sometimes I see a command like  find . -name * -exec ls -a {} \;   I was asked to execute this.  What does {} \; mean here?


Morphism to Projective Space $\mathbb{P}^m$

I'm going to prove following exercise from Bosch's "Algebraic Geometry and Commutative Algebra" (page 461):    I'm struggle with proving that if $m < n$ then the morphism $\varphi: \mathbb{P}^n_R \to \mathbb{P}^m_R$ must be constant.   I tried following:  Assume that we have such non constant $\varphi$. Then we get $m+1$ global sections $s_i \in \Gamma(\mathbb{P}^n, \mathcal{L})$ where $\mathcal{L}:= \varphi^*\mathcal{O}_{P^m}(1)$ where $s_i:= f^{\#}(t_i)$ for canonical $t_i \in \Gamma(\mathbb{P}^m, \mathcal{O}_{P^m}(1))= \oplus_{i=0}^m \mathcal{O}_{P^m}(0) \cdot t_i$.   Since $Pic(\mathbb{P}^n)= \mathbb{Z}$ we conclude $f^*\mathcal{O}_{P^m}(1)= \mathcal{O}_{P^n}(d)$ for a $d \ge 0$ (otherwise it would not have global sections.  Denote $U:= span(s_i \vert i \in \{0,1,...,m\})= <f^{\#}(t_i) \vert i \in \{0,1,...,m\}>_R $ the $R$-module subspace of $\Gamma(\mathbb{P}^n, \mathcal{O}_{P^n}(d))$.  Since the $t_i$ generate $\Gamma(\mathbb{P}^m, \mathcal{O}_{P^m}(1))$ then the pullbacks $s_i$ generate $\Gamma(\mathbb{P}^n, \mathcal{O}_{P^n}(d))$, therefore $U= \Gamma(\mathbb{P}^n, \mathcal{O}_{P^n}(d))$.   Since $m<n$ by assumption and $\Gamma(\mathbb{P}^n, \mathcal{O}_{P^n}(d)))$ is generated by exactly $n+1$ elements if $d>0$ and otherwise $\Gamma(\mathbb{P}^n, \mathcal{O}_{P^n}(0))=R$ is generated by one element, we conclude $d=0$.  So $\varphi^*\mathcal{O}_{P^m}(1) = \mathcal{O}_{P^n}$ is the structure sheaf and all it's global sections are constants. Therefore also $s_i$.  What I don't understand is why does it already imply that $\varphi$ is constant, so that $\varphi(\mathbb{P}^n)=pt$?  We consider now the construction for $\varphi: X \to P^m$ in detail. As in Hartshorne described it comes by glueing the restrictions $\phi_i: X_{s_i} \to D_+(t_i)$ via ring maps $k[t_0/t_i, ..., t_m/t_i] \to \Gamma(\mathcal{O}_X,X_{s_i}), t_j//t_i \mapsto s_j/s_i$. Since $s_i$ constants we get $X= X_{s_i}$ and therefore all $\varphi_i$ factorise over $Spec(\Gamma(\mathcal{O}_X,X)$. Then also $\varphi$ factorise through this affine scheme.  So that it indeed suffice to show that the composition $X_{s_i}\to Spec(\Gamma(\mathcal{O}_X,X) \to D_+(t_i)$ is already constant. But how?


Proof that $f$ is continuous if and only if $f$ composed with projections is continuous

Let $X,Y,Z$ be three topological spaces, let $X\times Y$ have the product topology, let $p_X:X\times Y\to X$ and $p_Y:X\times Y\to Y$ be projective maps, and let $f:Z \to X \times Y$ be a function.  I want to prove that $f$ is continuous if and only if $p_X \circ f: Z \to X$ and $p_Y \circ f:Z \to Y$ are continuous.  Given the fact that the projective maps are continuous, one direction is clear.  Now suppose $p_X \circ f$ and $p_Y \circ f$ are both continuous and let $U \times V \subseteq X \times Y$ be open. Then $U$ and $V$ are open in $X$ and $Y$ respectively, and $U \times V = p_X ^{-1}(U) \cap p_Y ^{-1}(V)$.  Thus $f^{-1}(U \times V) = f^{-1}(p_X ^{-1}(U) \cap p_Y ^{-1}(V)) = f^{-1}(p_X ^{-1}(U)) \cap f^{-1}(p_Y ^{-1}(V)) = (p_X \circ f)^{-1}(U) \cap (p_Y \circ f)^{-1}(V)$ is open in $Z$ as the intersection of two open sets. In this last step we used the continuity of $p_X \circ f$ and $p_Y \circ f$. Hence $f$ is continuous.  I am not entirely sure about this proof. I believe it contains some error, but I can't quite put my finger on it.  All remarks, corrections or improvements would be highly appreciated.  Edit: I should clarify what I mean by the product topology: Let $(X, \tau_X)$ and $(Y, \tau_Y)$ be topological spaces. $X \times Y$ is said to have the product topology $\tau$ if $\tau = \{ U\times V : U \in \tau_X , V \in \tau_V \}$. I hope this isn't too unorthodox a definition of the product topology. It is the one I have been working with all year. I am trying to prove the statement above using this definition of the product topology.  Second edit: In my previous edit, I gave a false definition of the product topology. It should be defined as the topology obtained from the basis $\{ U\times V : U \in \tau_X , V \in \tau_V \}$. In particular, this implies that if $U$ and $V$ are open in $X$ and $Y$ respectively, then $U \times V$ is open in $X \times Y$, but the converse is not necessarily true.


How to adjust the gap between figure and caption in subfloat

For the following example:  \begin{figure}     \centering     \subfloat[A]{\includegraphics[ scale=0.5]{images/a.jpg}}     \vspace{-10pt}     \subfloat[B]{\includegraphics[scale=0.5]{images/b.jpg}}     \vspace{-10pt}     \caption{}\label{fig:online_test} \end{figure}   I got the following figure:    The sub-caption of (a) is too close to the sub-figure B. How can I adjust the space between the caption and figure within a subfloat?  Thank you all for helping me and I would prefer a solution for subfloat, instead of using other packages. But I would also appreciate a solution of using other packages.   I know my question looks similar to . But please make it clear. I'm asking for how to adjust the gap between figure and caption within a subfloat, not the gap between two subfloat. That is, the gap between the caption "a" and the figure "A"!!!  I would keep arguing until my question get re-opened.


How does a scanner work with string comparison?

import java.util.Scanner;  public class teststuff {     public static void main(String[] args){         Scanner scan = new Scanner(System.in);               String test;         test = scan.next();          if(test == "example"){             System.out.println("it worked");         }     } }   Here's the code, and my input is "example" even though it's exactly the same it still doesn't give me a boolean true for my if statement. Is there something I'm doing wrong?


How Do I Connect PVC Pipe to a Toilet Waste Pipe?

I'm renovating a bathroom. How do I connect a PVC pipe and toilet flange to the existing steel or cast iron waste pipe?  Should I use PVC/DWV foam core pipe?  (I think that the existing pipe is steel, but it might be cast iron.)  Pls see the lovely view of the existing toilet waste pipe below:    Is this the coupling I should use?


QuickOSM query (in QGIS) appearing in the wrong place. Maybe CRS Problem?

I had a question in   which in turn made me to change my project CRS from EPSG: 3857 to EPSG: 25832.  My project location is in the middle of Germany (Shown in the image with the green dot, that i added manually)  But then, i queried some data from Quick OSM, only for it to appear somewhere in south of France. (Shown as the red dot)    At first I realized that the OSMquery layer have a different CRS than my project. (EPSG: 4326), so in turn, I changed the layer CRS from the OSMquery to my Project CRS, which is EPSG: 25832, but then this happened:     The red dot (Representing the layer with changed CRS) appears on the sea near the African Continent!  Did I do something wrong? Is there a way to repair this? Is there any command I have to change in the QuickOSM? Or is this a problem with the CRS? Or I just missed a setting somewhere? (Note: I am very new to GIS software in general)


I have a beamer class file, with a plenty of frames. Almost all frames need the option [fragile] because I frequently use \verb| | to illustrate codes.  So I want the frame to be equipped with [fragile] globally so that I don't need to type the option manually.  Also, I want all the stuff inside verbatim(or possibly inside \texttt, but I prefer verbatim) to be grey-shaded, just as TeX exchange is doing now.  Here is a minimal working example. Can you please modifiy it to resolve the issue?  \documentclass{beamer} \begin{document} \begin{frame}[fragile] % I used [fragile] since \verb in frame yields an error. \frametitle{fragile frame and shaded verbatim} \begin{itemize} \item I'm using the \verb|beamer| class. \item  want to set the \texttt{\colorbox{gray}{frame}} environment to be appended with the option \texttt{\colorbox{gray}{fragile}}. \item I want to set the stuff in the \texttt{\colorbox{gray}{verbatim}} command to be shaded just like \TeX exchange does. \item An ugly solution : \texttt{\colorbox{gray}{\textbackslash code\_example}} \end{itemize} \end{frame} \end{document}


"Follow" text should change to "Unfollow" when a question is followed

The behavior of the "follow" button is inconsistent with the other similar buttons under a question.  The labels on the other actions change to the opposite of their original label once an action is taken:   close -> reopen delete -> undelete follow -> following?   Shouldn't it be unfollow? In other cases, its' showing a label to reverse your action, not showing the current state of the action. It seems inconsistent.


Can I visit my British husband in the UK on a tourist visa for 6 months before applying for the spouse visa?

My understanding is that a requirement of the spouse visa is that the British citizen needs to show at least 6 months worth of payslips to prove income above £18,600.  I am a US citizen currently living in the US, while my British husband is living in the UK. He does make the minimum £18.6k but right now he cannot show 6 months consecutive payslips, as he was just recently visiting me in the US for 3 months. So since he's been back in the UK, he has only 2 months in a row to show and he will will not make it to 6 months since he needs to come back to the US for the birth of our first child. At that point, he will have worked for 5 months so he'll just miss it and will need to start over from 0 once he returns to the UK, so we can qualify to apply for a spouse visa for me.  My question is, am I allowed to come and stay with him (and our child) for 6 months on a visitor's visa while he is working? After the 6 months are up, I would go back to the US and apply for the spouse visa.  My concern is that immigration officials will not believe I intend on leaving the country after 6 months, especially if I have a British husband and child there and am not working myself. How can I prove that I am actually going to leave besides showing a return ticket, because I doubt that will be enough? I don't want to be denied entry into the country.  We do plan on applying for the visa, but in the meantime, we would like to be together with our firstborn while we wait to qualify for it.


Get the size (size in Kb or MB) of an featured image?

I need to display some featured image info on post page. Among other info I need to display file size of image (featured image of post).  I tried this function inside single.php.  <?php function getSize($file){    $bytes = filesize($file);    $s = array('b', 'Kb', 'Mb', 'Gb');    $e = floor(log($bytes)/log(1024));    return sprintf('%.2f '.$s[$e], ($bytes/pow(1024, floor($e)))); } ?>   and to echo that:  <?php echo getSize('/wp-content/uploads/2014/06/some-file-name.jpg'); ?>   It works, but I need help to make ti automatically grab featured image url, not to manually enter it in code?  For example I use this to echo featured image ("full") url:   <?php  if ( has_post_thumbnail()) {    $full_image_url = wp_get_attachment_image_src( get_post_thumbnail_id($post->ID), 'full'); echo $thumb_image_url[0];  } ?>    Could you please help to combine it, or to provide me with another solution?


How to add actuator, controller and action to series of objects?

I have a lot of object in my BGE environment. I can select them easily by using regular expression. All of them, also have action with specific name, too. Now I want to add them to my game, by python script. Is there any way to add actuator, controller and set action programmatically?


Why is light called an 'electromagnetic wave' if it's neither electric nor magnetic?

How can light be called electromagnetic if it doesn't appear to be electric nor magnetic?  If I go out to the sunlight, magnets aren't affected (or don't seem to be).  And there is no transfer of electric charge/electrons (as there is in AC/DC current in space).   In particular, the  (which light is supposed to be composed of) have no electric charge (nor do they have ).   I'm looking for an explanation that can be appreciated by the average non-physicist Joe.


Refresh Excel document without opening it

I have a spreadsheet which I want to upload onto my company's intranet for others to view. Everytime the spreadsheet opens, it runs a background script which updates the information. The problem is - the script runs for about 10 minutes because it looks at 2 huge tables. Is there a way for the spreadsheet to be refreshed once a day (example 2am) without someone having to open it?


Two days ago I had a full C: drive, after which I deleted 8 GB of data. The next day the hard drive was full again, so I continued with deleting another 5 GB, and once again the next day the disk was full.   After some searching for what caused the disk space to be filled so quickly, I used the windirstat tool to find which files took up the most space. I found out that the CBS.log file, which is located in c:\windows\logs\cbs\, is 20 GB large.  I am using Windows 8.   Should this file be this large, and if not, how can I reduce the size? What is the purpose of this file? Can I delete it?


I read some posts and parts of FHS to understand which directory I should install packages in. As far as I could understand /opt is for independent packages and /usr/local is for packages that are not maintained by distro repo's.   I want to install a network emulator called "mininet" on my Debian wheezy, so that all users can use it. It has an install.sh script which installs both types of packages: maintained by repo & not maintained by repo. As the first step of the installation I can indicate where I want my base directory to be. Now my question is which directory I should indicate as the base directory? should it be: "/usr/local", "/usr/local/mininet", "/usr/local/bin", "/usr/local/bin/mininet", "/opt" or some other directory?  I would appreciate if you could explain your answer too  Thank you.  EDIT: Should I specify the name of the package in the path like we do when installing in /opt (e.g. /usr/local/mininet/) or I shouldn't?


Using LWC and an Imperative APEX method, I cannot reference the parameter being passed into APEX because it is a promise

I have an apex method which receives a country name and returns a country code.  @AuraEnabled (cacheable = true) public static String getCountryCode(String searchString) {     //TODO add the code to lookup the country code     String result = 'test';     System.debug('ALH searchString='+searchString);     System.debug('ALH result='+result);     return result; }    I will add the logic later to do the lookup, for now I am just trying to get the searchString into the apex method.  Here is part of my js code  import getCC from '@salesforce/apex/NewAccountController.getCountryCode';   @track searchCountry; @track searchCountryCode; @track foundCountryCode;  grabCC() {       const searchccId=this.searchCountry;                 if (searchccId) {                 getCC ( {searchccId} )                      .then(result => {                         this.searchCountryCode = result;                         this.foundCountryCode=true;                         }                         })                     .catch (error => {                         console.log('catch error ' + error.message);                     }); }}   When I look at my debug log in for the APEX code it shows: ALH searchString=null ALH result=test  I understand that the input string is a "promise", but how can i force it to be passed in so that I can use the searchString in my APEX code?


Looking for a novel with a travelling storyteller, dragons and human-animal hybrid underclass

I am looking for a novel that I read when I was a teenager (late 90s to early 00s). I don't think I ever finished it so I would like a chance to do so but I can't remember the name! Hopefully the following description is not too vague.  The main character was a human who trained as some sort of travelling storyteller. At the start of the story the country/kingdom that the character lives in is coming under attack from another country/kingdom overseas. A big part of he story was the tension between humans and a human-animal servant class that were usually described by which animal they most closely represent (equine, bovine etc). I'm pretty sure there were also dragons in the world, although they may have been absent for quite a while.


Showing $x^4-16x^2+4$ is irreducible over $\mathbb{Q}$  Is there a slick way to do this? I mean first we could perhaps show it has no roots in $\mathbb{Q}$ by substituting dummy variable $t$ and solving $t^2-16t+4=0$, and then show that it doesn't factor as two quadratics by trying to match coefficients. Is there a better way to do this?