I know that an integer is the sum of two squares if and only if it is the norm of some Gaussian integer. However, the numbers below are so large I don't even know where to begin, let alone know whether or not it can even be a sum of two squares.  5^7 * 7^9 * 11^12 * 13^11 2^10 * 11^12 * 13^15 * 23^11 3^11 * 7^10 * 13^12 * 17^13 3^8 * 7^12 * 13^5 * 19^4

I'm looking for some help disproving an answer provided on a  I posted about computing the number of double square combinations for a given integer.    The original question is from the Facebook Hacker Cup       Source: Facebook Hacker Cup   Qualification Round 2011      A double-square number is an integer $X$   which can be expressed as the sum of   two perfect squares. For example, 10   is a double-square because $10 = 3^2 + 1^2$.   Given $X$, how can we determine the   number of ways in which it can be   written as the sum of two squares? For   example, $10$ can only be written as $3^2 + 1^2$   (we don't count $1^2 + 3^2$ as being different). On the other hand,   $25$ can be written as $5^2 + 0^2$ or as   $4^2 + 3^2$.      You need to solve this problem for $0 \leq X \leq 2,147,483,647$.      Examples:      $10 \Rightarrow 1$      $25 \Rightarrow 2$      $3 \Rightarrow 0$      $0 \Rightarrow 1$      $1 \Rightarrow 1$   In response to my original question about optimizing this for F#, I got the following response which I'm unable to confirm solves the given problem correctly.       Source:       Again, the number of integer solutions   of $x^2 + y^2 = k$ is four times the   number of prime divisors of $k$ which   are equal to $1 \bmod 4$.      Knowing this, writing a program which   gives the number of solutions is easy:   compute prime numbers up to $46341$ once   and for all.      Given $k$, compute the prime divisors of   $k$ by using the above list (test up to   $\sqrt{k}$). Count the ones which are   equal to $1 \bmod 4$, and sum. Multiply   answer by $4$.   When I go through this algorithm for $25$, I get $8$ which is not correct.          For each prime factor (pf) of $25$ ($5$, $5$ are prime factors of $25$)         if pf % $4$ = $1$ (true for both $5$'s), add $1$ to count      return $4$ * count (count would be $2$ here).          So for $25$, this would be $8$


TNG's Galaxy-class Enterprise-D could theoretically get to warp 9.8 and sustain warp 9.6 yet there are a number of perilous situations where "maximum warp" wasn't used.  The one that most recently caught my eye is . JLP found out that Data was not destroyed and was likely abducted and went to rescue him... At Warp 8.     LAFORGE: What if Data wasn't on that shuttle?   PICARD: Mister Crusher.   WESLEY [OC]: Aye, sir.   PICARD: Set course for the site of the shuttlepod explosion. Warp eight.   WESLEY [OC]: Aye, sir.   They'd been travelling away from the site of the explosion at warp 6 for 23 hours. That's about 1 light year. The time to backtrack that distance :   Around 8 hours at warp 8 Under 5 hours at warp 9.2 Under 3 hours at 9.6 Under 2 hours at warp 9.8   So my question is, why would Picard leave a bridge officer stranded, in danger for an extra 3-6 hours when he had the opportunity to go faster?

How does Picard, or anyone for that matter, decide at what warp speed to travel?  Obviously there are times when they need to get somewhere in a hurry and he says, warp 9 or maximum warp, but the rest of the time he just seems to pick a number at random. He rolls a warp 6.5 Is there some guide as to recommended speeds that he's following? Is there a speed that is the most efficient?


If reviewers make a decision to accept/reject a suggested edit, does the original poster have a way to overturn their decision?  I've made a few edits that were rejected by reviewers. I thought they were improvements to the site that would help others in the future, but it seems they did not fit within SO policy.  It is my impression that the OP is in the best position to decide whether or not an edit is an improvement because rather than being responsible for impartially interpreting a policy, they need only to decide whether the change improves their question or answer.  So, I would like to know if the OP is notified of edits and given an opportunity to accept or reject them, should they have an interest in doing so.

When clicking "edit" I see:  Your edit will be placed in a queue until it is peer reviewed. We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.  Like:     Likewise, when I am not logged in, clicking "improve this question" or "improve this answer" shows:  You are not . Your edit will be placed in a queue until it is .  And when I click 'Save', I get:  Thanks for submitting an edit. It is only visible to you until it's been approved by trusted community members  Like:     Who can suggest an edit? Where do suggested edits go? Who can vote on a suggested edit? How do suggested edits get reviewed? Can I earn reputation? What about abuse or bad edits? Sometimes the Community user approves or rejects my edit. Why is that? When can I not suggest an edit? Is there a minimum change requirement for a suggested edit? How do I check my suggested edit history? I disagree with the reasons why my suggested edit was rejected. What can I do? How do I know whether there are edits waiting for review? Someone suggested an edit to my own post, and the reviewers took the wrong action. What can I do? Are tag wikis included in this scheme? What do the "Improve Edit" and "Reject and Edit" buttons do? Why are apparently valid links to rejected edits resulting in 404 errors?   For more information about editing, see "" in the .


After installation no boot option to choose but directly loading up windows 10 1903, can someone know why? my setup was UEFI, disabled secure boot, boot up with liveusb and with connectivity.

I installed Ubuntu on a Dell XPS 13 laptop that had Windows 10 preinstalled on it. I installed it from a USB flash drive on a partition. When I boot my computer I can only boot into Windows 10 and Ubuntu is nowhere to be seen.  If I boot into my USB then I can see that Ubuntu is installed, but I can't get to it from the BIOS boot menu.


I am trying to install the old (holo) version of Google Play Music on my device (  - VERSION    Google_Play_Music_v4.4.811H.526848.apk to be exact ) because I only use local media files and the new orange cremesickle version from the past year or so is terrible at this and I loathe it.  However, my roomates have an All Access Subscription which requires the new version, leading to a lot of tension over what version to keep on the device.  I have read that it is possible to install two versions of an app side by side by changing the package name via APKtool. This seems like a trivial thing to do, but it is not working for me.  Following the guide at  i attempted to change the package name, but the line 'cur_package_name' and 'orig_package_name' are not in my apktool.yml, and there is an additional 'original-package' entry in the androidmanifest alogside the line with the package attribute.  Also, upon doing the find-replace trick with notepad++ that they mentioned, it is unable to find any occurrences.  Where can I go from here? I attempted to recompile and run the app on the tablet, but it force closes immediately as something is incomplete. Is there a version of this app that is already modded for side by side loading out there? or how can I proceed?

Android Market has just updated an app in my device. I liked the update, but its fully different from last version which was also my favorite. So, I want to keep last version too. I have last version's apk thanks to Titanium Backup. But, I can't install it without replacing current one (Android architecture sucks). Is there any way to do this? Hacks etc.. Note: I want to keep current version which must be connected with Market to receive future updates.


I have a class with an attribute I don't want to be null.  Si in the setter looks like this :  public void setFoo(String bar) {     if (bar == null)         throw new IllegalArgumentException("Should not be null");     foo = bar; }   And in my JUnit test case, I would like to assert that if I do obj.setFoo(null), it will fail. How can I do this?

How can I use JUnit4 idiomatically to test that some code throws an exception?  While I can certainly do something like this:  @Test public void testFooThrowsIndexOutOfBoundsException() {   boolean thrown = false;    try {     foo.doStuff();   } catch (IndexOutOfBoundsException e) {     thrown = true;   }    assertTrue(thrown); }   I recall that there is an annotation or an Assert.xyz or something that is far less kludgy and far more in-the-spirit of JUnit for these sorts of situations.


I know, this is a very stupid question and the answer is out there in Googleland. But I just can't find it.  I want to start a process/program (e.g. firefox) in bash and keep working with the terminal. Is there a way to do this?  Thanks in advance, Markus

I use dwm as a window manager on Ubuntu, I like tiled windows and I like them as few as possible. I sometimes need to run an application (let's say it's the pdf viewer mupdf in x11) from the terminal, the application will be launched in a new window but the terminal from which I launched becomes this prompt-less console for that application to log whatever.  I use dmenu to launch applications, but sometimes an application needs arguments (file names) to start. I use uxrvt within x11 managed by dwm.


I have Windows 10 running on my laptop which has 8GB RAM. I want to install Ubuntu in virtual box and I also want to install docker in it. How much RAM would you suggest me to allocate? Thanks

I'm thinking about installing Ubuntu Desktop, but I don't know what flavor is the best for my system. What are the minimum and recommended hardware requirements? What kind of CPU? How much memory? Should I have Hardware Acceleration? What flavor should I use?  This is an attempt of a canonical answer. My answers have the "official  requirements", the recommended are a mix of official sources and opinion based (along with the answer it's told the source). You can comment or edit if you feel that the information is obsolete or incomplete. It is a good rule of thumb that any system capable of running Windows Vista, 7, 8, x86 (Intel) OS X will almost always be a lot faster with any Ubuntu flavor even if they are lower-spec than described below.


This is my first time posting. I need to do the above upgrade.  I am not very tech savvy; a friend switched me from windows to linux some yrs ago. I am familiar with using the terminal a bit. Can someone please advise how to do the upgrade?

As per title, I wish to know if I can, after a successful 32bit setup and consequent software installations, update to a 64bit version.  I know how to partition (actually one of the solutions is to set /, /etc, /home, /var/www, and /opt as separate partitions) and I know that a clean install is way better than a dirty one, yet I would like to know if/how it's possible to do that.


I’ve just learned about cell division and I noted that plant cells don’t have centrioles but still undergo cell division. I’ve read a few documents about it and wondered why plant cells don't have centrioles.  How is it that plant cells can divide without centrioles?

Most plants do not have centrioles, so what organelle enables them to multiply?


OK, my first question in stackOverflow.   This is something that I left me completely baffled.  Java (I use android Studio), I write the following code:      Integer aNumber = 200;     String aNumberInString;     aNumberInString = Integer.toString(aNumber);     Boolean result;     if(aNumberInString == "200"){         result = true;     } else {         result = false;     }      Log.i("result:",result+"");   OK, logic and what I expect is that the condition is true... But NO! it fails.  I was really shocked by this behavior, then investigate a little more, and run the code in debug mode step by step.  when I get to the condition, I inspect the value of "aNumberInString" and to my surprise, this is what I find:    OK, so the first thing I think is: "Integer.toString ()" are doing something wrong.  Let's try another way: "String.valueOf ()"  Run in debug mode, and:    THE SAME! and fails, of course.  Obviously fails because it compares different characters, and in Internet I found a way to fix it,  string.replace ("\\ u0000", "");   but my question is not how to fix it, is:   Why is this happening?  Is there a correct way to prevent this from happening?  From already thank you very much to all, Regards, Nicolas

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


I had changed my Facebook username (once) and Facebook doesn't allow me to change it twice. So I want to change it back to the old one. Is this possible? Or, are there any methods to change the username twice?

Do I have to re-register a new Facebook account to change my facebook.com/USERNAME?  Or are there any ways to change it?


I'd like to know why this means forever. As a foreign English speaker, when I heard this idiom I thought it meant like for something good.  What was the origin of "for good" ?

A very recent and similar  was closed asks what "for good" means.  While general reference can answer the question, I became curious as to the etymology of the idiom.   around got me nowhere, which is unusual.  The closest I found was a thread in :     OED   for good (and all): as a valid conclusion; hence, as a final act, finally.    15.. Parl. Byrdes Aij, Than desyred al the Byrdes great and smal to mewe the hauke for good and all. 1603 in Crt. & Times Jas. I (1849) I. 25 D’Auval.. is gone for good and all. 1687 CONGREVE Old Bach. I. i, Ay, you may take him for good-and-all if you will. 1711 SWIFT Jrnl. to Stella 4 July, This day I left Chelsea for good, (that’s a genteel phrase). a 1732 T. BOSTON Crook in Lot (1805) 37 He was obliged for good and all to leave his country. 1850 J. H. NEWMAN Diffic. Anglic. 324 Throw off, for good and all, the illusions of your intellect. 1882 W. E. FORSTER Let. To Gladstone 10 Apr. in T. W. Reid Life (1888) II. viii. 421 This morning we released Parnell—not for good, but on parole.   However, this only traces some historical usages, and suggests that for good and all used to be a more popular version of the current idiom.  Is there anything more substantial?  Why did "for good" come to mean "forever"?


Why does the following method only check the first character in the supplied string?  public static bool IsUnicodeSms(string message) {    var strMap = new Regex(@"^[@£$¥èéùìòÇØøÅå_ÆæßÉ!""#%&'()*+,-./0123456789:;<=>? ¡ABCDEFGHIJKLMNOPQRSTUVWXYZÄÖÑÜ§¿abcdefghijklmnopqrstuvwxyzäöñüà^{}\[~]|€]+$");    return !strMap.IsMatch(message); }   So for example the following string returns false: "abcლ" but "ლabc" returns true.

I am tired of always trying to guess, if I should escape special characters like '()[]{}|' etc. when using many implementations of regexps.  It is different with, for example, Python, sed, grep, awk, Perl, rename, Apache, find and so on. Is there any rule set which tells when I should, and when I should not, escape special characters? Does it depend on the regexp type, like PCRE, POSIX or extended regexps?


My mum and dad are planning on visiting my sister in the UK. My dad is an EU citizen but my mom is not. She does have a residence permit in Italy though (I think it's called permesso di soggiorno).   I've read about EU citizens being able to travel with their non-EU spouses if they have an article 10 residence permit (see link below) so I wanted to ask if her residence card qualifies as an article 10 permit and if she can travel with my dad without having to apply for a visa?

I have an Italian permesso di soggiorno and I want to join my husband in the UK. My baby and my husband are Italian nationals. Can I travel with them with only the permesso di soggiorno?


I want to schedule my Win10's system display to automatically wake up at the same time every day.  The display automatically goes to sleep on idle (computer is still running - just display off).  I already have an event profile set up in Task Scheduler but need the right action to do this.    Need an integrated Windows-native solution that doesn't require third party tools. The marked duplicate does not have a solution like that.    Here is a proper duplicate:   With answer:

It doesn't seem like this would be very difficult, but how can I wake-up a PC by doing the equivalent of moving a mouse or pressing keys on a keyboard?  My PC is running Windows 10 and I only have the monitors enter sleep mode after 15 minutes.  The rest of the PC is still awake and doesn't use hibernate, etc.  I'm trying to use EventGhost to receive a TCP/IP command that tells the PC to wake up the displays but it's proving quite difficult.


I want to start Zookeeper daemon after Ubuntu server 16.04 booting (not after logging) under user named zookeeper. So I changed the file /etc/rc.local like the following:  #!/bin/sh -e # # rc.local # # This script is executed at the end of each multiuser runlevel. # Make sure that the script will "exit 0" on success or any other # value on error. # # In order to enable or disable this script just change the execution # bits. # # By default this script does nothing.  echo 'never'; defrag_file_pathname  su -c '$ZOOKEEPER_HOME/bin/zkServer.sh start' zookeeper &  exit 0   , adding the line su -c '$ZOOKEEPER_HOME/bin/zkServer.sh start' zookeeper & before exit 0. But the process is not started after restarting!  What's wrong here?  details: The zookeeper user is in sudo group and has password.  details: When I run command su -c '$ZOOKEEPER_HOME/bin/zkServer.sh start' zookeeper & in terminal, it needs password to run.

I would like to run a script from the main ubuntu shell as a different user that has no password.  I have full sudo privileges, so I tried this:  sudo su -c "Your command right here" -s /bin/sh otheruser   Then I have to enter my password, but I am not sure if that script is now really running under that user.  How can I confirm that the script is really running under that user now?


Is there any software, like Grammarly, that enables one to check the grammar in the text while using latex. The problem with using Grammarly is that with formulas and mathematical notation, it becomes very tedious to use Grammarly.

I am looking for a grammar-checking tool, i.e., something that checks for mistakes such as "two dog" or "a books".  It has to work on Linux (Ubuntu).  Also, since I use macros to generate some of the prose, it has to somehow work with LaTeX.  I don't think that such checkers are LaTeX-aware, so it has to work with some compilation product of LaTeX: DVI or PDF.    If you suggest a grammar checker that checks plain text, please explain how to you extract the text.  catdvi does a nice job, but it leaves some garbage like page numbers.


I had an exam where I had to prove or disprove that the language $L=\{w^{|w|} | w \in \Sigma^*\}$ where $\Sigma = \{0,1\}$ is regular. On a glance, it looked regular to me so I tried using induction to prove that it is in fact, regular. Here's what I did: Let $|w|=n$. We will use induction over $n$ to prove $L$ is regular.  Base: Let $n=1$. Then we have $|w|=1$, so $w$ is made up of one letter (either 0 or 1) and $L = w^1=\{0,1\}$. Then $L$ is finite and therefore regular. Hypothesis: Let's assume that our claim is true and $L$ is regular for a given $n$ (that is $L=\{w^n\}$ is regular). We will now try to prove that $L$ is regular for $n+1$ Step: If $|w|=n+1$, then $L=\{w^{n+1}\}=\{w^n.w\}$. From our hypothesis we get that $w^n$ is regular. Since our $n$ is not infinite we know that $w$ is finite and as such there exists a regular expression that recognizes $w$. Which means that $w$ is regular as well. Now we have that $L=\{w^n.w\}$ is a concatenation of two regular languages which means that L is regular as well.  I had 0 points given for that answer. Unfortunately we are not allowed to see our mistakes or possible solutions as that problem was a part of the graduation exam in my country so I have no idea where I got wrong. I would greatly appreciate if you could point where I've made a mistake and point me to a possible solution. P.S. After the exam I came up with something proving that the language is not regular using the pumping lemma but I will probably post it a bit later

Is it true that for every regular language $L \subseteq \{0,1\}^*$, language $\big\{ w^{|w|} \big| w \in L \big\}$ is regular? I don't know how to prove that.Could you give me a hint? Thank you


I am using a HP Envy Laptop, 256 GB SSD and 8 Gb Ram. I want to install Ubuntu 18.04.4. LTS. what are the partitions i need and what is the best size and which filesystem i shall use for each.  How much disk space shall i allocate for:  / /boot /usr /var /opt /tmp swap what others i need to add?  please suggest.

I would like to see a full how-to guide on how to install Ubuntu.


my professor has assigned a project where we need to make a reverse polish calculator in C (input in postscript syntax). I'm currently working on a method to find the length of the array of values I have scanned in (via .txt file). My current method is  int length(int list[]) {     int c = 0;     while(0 == 0) {         if(list[c] != '\0') {c++;}         else {break;}     }      return c; }   and the call for it is   int sizeA = length(list); printf("\n%d\n", sizeA);   It's currently only outputting the length as 0. Does anyone know why that might be and a fix to this method? Thanks

How do I determine the size of my array in C?   That is, the number of elements the array can hold?


The following  is an answer for why lm.ridge and glmnet results are different and how to solve that. My question is different since I am asking which functions are more trusted to use because they are giving different results each time when compared with textbook calculation. I am working with ridge regression in R. I have three functions to use which are glmnet or lm.ridge or textbook calculation. I can make the glmnet results as textbook calculation results. p.tmp <- 5 n.tmp <- 30  set.seed(123) X=scale(matrix(rnorm(n.tmp*p.tmp),ncol = p.tmp)) Y=scale(rnorm(n.tmp))  set.seed(123)  ridge.fit.cv <- cv.glmnet(X, Y, alpha = 0, standardize = FALSE, intercept = FALSE) ridge.fit.lambda <- ridge.fit.cv$lambda.1se ridge_mod <- coef(glmnet(X, Y, alpha=0, standardize = FALSE,   lambda = ridge.fit.lambda) )[-1] ############################### ridge.coef.DEF = solve(t(X) %*% X + n.tmp* ridge.fit.lambda * diag(p.tmp)) %*% t(X) %*% Y cbind(glmnet=c(ridge_mod),textbook=c(ridge.coef.DEF), lm.ridge=c(coef( lm.ridge(Y~X - 1, lambda=ridge.fit.lambda))))  The results as follows           glmnet      textbook     lm.ridge X1  3.040157e-04  3.092039e-04  0.009102455 X2  9.805261e-04  9.972422e-04  0.028596273 X3  1.514714e-04  1.540631e-04  0.004855324 X4  1.721871e-04  1.751177e-04  0.004789519 X5 -4.282657e-05 -4.355457e-05 -0.001143931  Or I can also make lm.ridge results as textbook calculation as giving below set.seed(123)  ridge.fit.cv <- cv.glmnet(X, Y, alpha = 0, standardize = FALSE, intercept = FALSE) ridge.fit.lambda <- ridge.fit.cv$lambda.1se ridge_mod <- coef(glmnet(X, Y, alpha=0, standardize = FALSE,   lambda = ridge.fit.lambda) )[-1] ############################### ridge.coef.DEF = solve(t(X) %*% X + ridge.fit.lambda * diag(p.tmp)) %*% t(X) %*% Y cbind(glmnet=c(ridge_mod),textbook=c(ridge.coef.DEF), lm.ridge=c(coef( lm.ridge(Y~X - 1, lambda=ridge.fit.lambda*(30/29)))))  The results as           glmnet     textbook     lm.ridge X1  3.040157e-04  0.008815056  0.008815056 X2  9.805261e-04  0.027715213  0.027715213 X3  1.514714e-04  0.004692398  0.004692398 X4  1.721871e-04  0.004649196  0.004649196 X5 -4.282657e-05 -0.001112091 -0.001112091  My question is which method I should believe because as you notice the results are different. Should I make the text calculation as glmnet or as lm.ridge?

I applied some data to find the best variables solution of regression model using ridge regression in R. I have used lm.ridge and glmnet (when alpha=0), but the results are very different especially when lambda=0. It suppose that both parameter estimators have the same values. So, what is the problem here?   best regards


I am new in core java and wrote a nested if statement code. I'm facing the problem when nested condition is satisfied and print statement "you will get 40% discount of fair" is not getting executed. import java.util.Scanner;  public class Ifstatement {     static int age ;     static String Gender;      public static void main(String[] args) {         Scanner obj = new Scanner (System.in);         System.out.print("Enter the age: ");         age = obj.nextInt();         System.out.print("Enter the Gender: ");         Gender= obj.next();         System.out.println("Gender is "+ Gender);         System.out.println("Age is "+ age);                  if (age<=14)          {             System.out.println(" you will get 30% discount of fair ");                          if(Gender== "F")              {                 System.out.println("you will get 40% discount of fair");             }                      }                  if (age>=14)          {             System.out.print("you will get 20% discount of fair");         }              } }

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


I have a problem! I have a bunch of image files with extensions. Jpg and. Png. I wrote a script that renames the files, changing their names in a pattern followed by a number like this:  ... arquivo_1.jpg arquivo_2.jpg ...   And following this sequence, but it needs to know the extension, in this case I used the extension. Jpg.  I was wondering how do I optimize the script so that it renames but keeping the original extension of the file and keep doing the sequence I described above. Can someone help me?

I am looping through a number of files, and $file represents the current file.  How can I make copies or renames and keep the extension the same for this current file?  e.g. if $file = x.jpg  How to make a copy of $file's with a filename of x_orig.jpg  So far I have:  for file in /tmp/p/DSC*.JPG; do   cp $file $file+'_orig'.JPG done   but that copies the file  DSCF1748.JPG   to  DSCF1748.JPG+_orig.JPG   whereas I want a copy named  DSCF1748_orig.JPG   Similarly, using cp $file "$file"_orig.JPG  results in files such as DSCF1748.JPG_orig.JPG  I want to get the _orig in the middle of the filename...


Emacs is build from the , which is based on the  (which is not maintained any more).   The cassou PPA only has 24.3 builds available.   Do you know any other ways to install it on Ubuntu? Maybe some PPAs or deb packages (now I'm trying to build it from source)?

I'm running the latest Kubuntu (12.04 beta 2) and I would like to run the latest emacs (currently v24). The repos are one version behind. What's the best way to install v24 or later (and avoid future version conflicts)?  Also, is there any reason not to aways use the GUI version of emacs if X is running? For example, could I set the GUI emacs version as the default text editor and use it to edit cron jobs (crontab -e)? I'm assuming the answer is yes, but since I haven't done that yet (my default editor is nano), I want to check if there are reasons I should leave nano as the default editor.  Usually when I'm working on the command line I end up using nano. Now that I think about it, I have no idea why I keep doing that. Is there any downside to calling a GUI editor when working in an X terminal?  EDIT: I briefly tested these two versions   GNU Emacs 24.0.94.1 (x86_64-pc-linux-gnu, GTK+ Version 3.3.20) from  GNU Emacs 23.3.1 (x86_64-pc-linux-gnu) installed by default in Kubuntu.   .  Unfortunately (for me) the defaults installed version (23.3.1, 23.3+1-1ubuntu9) is the nox version.   Package: emacs23-nox Status: install ok installed Version: 23.3+1-1ubuntu9 Replaces: emacs23, emacs23-gtk, emacs23-lucid   The package with version 24 opens in GUI mode by default. That's what I prefer. Some of the version 24 changes that interest me are listed in the references below.   But there appear to be a multitude of different packages and versions I could install.  References:   What’s New In Emacs 24 (part 1) | Mastering Emacs  "    shell-mode uses pcomplete rules, with the standard completion UI.  Yowzah! There’s a lot of cool, new functionality hidden away in this gem of a change." EmacsWiki: Recent Changes


One of my systems (16.04) has disk space left:  root@ip-172:/# df -k Filesystem     1K-blocks    Used Available Use% Mounted on udev              284388       0    284388   0% /dev tmpfs              60120    6596     53524  11% /run /dev/xvda1       8125880 4530864   3159204  59% / tmpfs             300596       0    300596   0% /dev/shm tmpfs               5120       0      5120   0% /run/lock tmpfs             300596       0    300596   0% /sys/fs/cgroup tmpfs                100       0       100   0% /run/lxcfs/controllers tmpfs              60120       0     60120   0% /run/user/1000   When starting apt-get, I get errors due to missing disk space:  root@ip-172:~# apt-get -f install Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following packages were automatically installed and are no longer required:   linux-headers-4.4.0-24 linux-headers-4.4.0-24-generic linux-headers-4.4.0-28 linux-headers-4.4.0-28-generic   linux-headers-4.4.0-31 linux-headers-4.4.0-31-generic linux-headers-4.4.0-34 linux-headers-4.4.0-34-generic   (...) Suggested packages:   fdutils linux-doc-4.4.0 | linux-source-4.4.0 linux-tools The following NEW packages will be installed:   linux-headers-4.4.0-66 linux-headers-4.4.0-93 linux-headers-4.4.0-93-generic linux-image-4.4.0-93-generic 0 upgraded, 4 newly installed, 0 to remove and 174 not upgraded. 5 not fully installed or removed. Need to get 0 B/42.7 MB of archives. After this operation, 215 MB of additional disk space will be used. Do you want to continue? [Y/n] (Reading database ... 515059 files and directories currently installed.) Preparing to unpack .../linux-headers-4.4.0-66_4.4.0-66.87_all.deb ... Unpacking linux-headers-4.4.0-66 (4.4.0-66.87) ... dpkg: error processing archive /var/cache/apt/archives/linux-headers-4.4.0-66_4.4.0-66.87_all.deb (--unpack):  unable to create '/usr/src/linux-headers-4.4.0-66/sound/usb/hiface/Makefile.dpkg-new' (while processing './usr/src/linux-headers-4.4.0-66/sound/usb/hiface/Makefile'): No space left on device No apport report written because the error message indicates a disk full error                                                                               dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Preparing to unpack .../linux-headers-4.4.0-93_4.4.0-93.116_all.deb ... Unpacking linux-headers-4.4.0-93 (4.4.0-93.116) ... dpkg: error processing archive /var/cache/apt/archives/linux-headers-4.4.0-93_4.4.0-93.116_all.deb (--unpack):  unable to create '/usr/src/linux-headers-4.4.0-93/arch/x86/include/asm/pvclock.h.dpkg-new' (while processing './usr/src/linux-headers-4.4.0-93/arch/x86/include/asm/pvclock.h'): No space left on device No apport report written because the error message indicates a disk full error                                                                               dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Preparing to unpack .../linux-headers-4.4.0-93-generic_4.4.0-93.116_amd64.deb ... Unpacking linux-headers-4.4.0-93-generic (4.4.0-93.116) ... dpkg: error processing archive /var/cache/apt/archives/linux-headers-4.4.0-93-generic_4.4.0-93.116_amd64.deb (--unpack):  unable to create '/usr/src/linux-headers-4.4.0-93-generic/include/config/x86/cmpxchg64.h.dpkg-new' (while processing './usr/src/linux-headers-4.4.0-93-generic/include/config/x86/cmpxchg64.h'): No space left on device No apport report written because the error message indicates a disk full error                                                                               dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Preparing to unpack .../linux-image-4.4.0-93-generic_4.4.0-93.116_amd64.deb ... Done. (...)   I still have 3GB left on / so I do not understand which disk exact space is missing?   Just in case I forced an fsck on reboot (and rebooted) but the issue is still there.

I was trying to update my packages today:  $ sudo apt-get upgrade Reading package lists... Done Building dependency tree        Reading state information... Done You might want to run 'apt-get -f install' to correct these. The following packages have unmet dependencies:  linux-headers-3.16.0-44-generic : Depends: linux-headers-3.16.0-44 but it is not installed E: Unmet dependencies. Try using -f.   So, I went ahead and tried apt-get -f install:  $ sudo apt-get -f install Reading package lists... Done Building dependency tree        Reading state information... Done Correcting dependencies... Done The following extra packages will be installed:   linux-headers-3.16.0-44 The following NEW packages will be installed:   linux-headers-3.16.0-44 0 upgraded, 1 newly installed, 0 to remove and 3 not upgraded. 3 not fully installed or removed. Need to get 0 B/9,101 kB of archives. After this operation, 64.5 MB of additional disk space will be used. Do you want to continue? [Y/n] y (Reading database ... 688666 files and directories currently installed.) Preparing to unpack .../linux-headers-3.16.0-44_3.16.0-44.59_all.deb ... Unpacking linux-headers-3.16.0-44 (3.16.0-44.59) ... dpkg: error processing archive /var/cache/apt/archives/linux-headers-3.16.0-44_3.16.0-44.59_all.deb (--unpack):  unable to create `/usr/src/linux-headers-3.16.0-44/scripts/genksyms/Makefile.dpkg-new' (while processing `./usr/src/linux-headers-3.16.0-44/scripts/genksyms/Makefile'): No space left on device dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Errors were encountered while processing:  /var/cache/apt/archives/linux-headers-3.16.0-44_3.16.0-44.59_all.deb E: Sub-process /usr/bin/dpkg returned an error code (1)   It's complaining saying No space left on device. df -Th tells me that there's sufficient space:  $ df -h Filesystem      Size  Used Avail Use% Mounted on /dev/sda6       3.3G  2.5G  571M  82% / udev            2.0G     0  2.0G   0% /dev tmpfs           395M   11M  384M   3% /run tmpfs           2.0G   28M  1.9G   2% /dev/shm tmpfs           2.0G     0  2.0G   0% /sys/fs/cgroup tmpfs           100M   72K  100M   1% /run/user tmpfs           5.0M  8.0K  5.0M   1% /run/lock /dev/sda7       9.3G  7.6G  1.3G  87% /usr /dev/sda8       188G  176G  3.0G  99% /home /dev/sda1       945M  394M  487M  45% /boot /dev/sda9       256G  9.6G  233G   4% /var   However, df -i tells me /usr has used up all the inodes.  These are the dirs and their inode usage:  /usr/bin = 2846 /usr/etc = 1 /usr/games = 8 /usr/include = 3204 /usr/lib = 42317 /usr/local = 105 /usr/lost+found = 1 /usr/sbin = 306 /usr/share = 228141 /usr/src = 348704   So, if I can clear out /usr/src (which contains the current and old kernels), I can probably resolve the issue. But, I keep running into the first error:  $ sudo apt-get purge linux-image-3.8.0-35-generic  Reading package lists... Done Building dependency tree        Reading state information... Done You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies:  linux-headers-3.16.0-44-generic : Depends: linux-headers-3.16.0-44 but it is not going to be installed  linux-image-extra-3.8.0-35-generic : Depends: linux-image-3.8.0-35-generic but it is not going to be installed E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).   Any suggestions on how I can remove my old kernels? Thanks!


What is the word for "saying a lot but unable to make a point or deliberately refrain from making a point"?

I know many politicians that avoid interview questions by talking a lot but not really communicating anything.  You could say that what they were saying was full of banalities or canned answers or that they were waffling, but is there a better word for this behaviour?  I'd like to say some thing like That response was a _____ or he\she is ___ing?


The first benefit of the  feat says (PHB, p. 168):  When you take the Attack action and attack with only a glaive, halberd, quarterstaff, or spear, you can use a bonus action to make a melee attack with the opposite end of the weapon.  Does this additional attack clearly occur after the attack with the main weapon? Or is there a time to use it between the attack being "declared" and resolving the main attack? Background/motivation: I would like to attempt the following:  Announce I am attacking Bandit Keith; Use the bonus action to attack with my halberd's shaft, with a Tripping Attack maneuver; Assuming success on the attack / STR check, attack with the halberd blade at advantage;  While that appears to fit how the flow of a fight works in my head, the word take appears a bit ambiguous to me if I wish to argue from RAW. If an action is taken, does this mean it must be completely resolved?

The rules on  state:     When you take the Attack action and attack with a light melee weapon that you’re holding in one hand, you can use a bonus action to attack with a different light melee weapon that you’re holding in the other hand.   However, the description of  states:     You choose when to take a bonus action during your turn, unless the bonus action’s timing is specified   So, can you attack with your bonus action first?


When I define amsthm theorem environments with shared counters, autoref messes up the names of the references. For example, in the output below, we should have "Definition 2" instead of "Theorem 2".  \documentclass{article}  \usepackage{amsthm} \usepackage{hyperref}  \theoremstyle{theorem} \newtheorem{theorem}{Theorem} \theoremstyle{definition} \newtheorem{definition}[theorem]{Definition}  \begin{document}  \begin{theorem} \label{wonderful-theorem} This is a wonderful theorem. \end{theorem}  \begin{definition} \label{awesome-definition} This is an awesome definition. \end{definition}  Look at the wonderful \autoref{wonderful-theorem} and the awesome \autoref{awesome-definition}.  \end{document}

I have some own theorem environments. And my theorems are numbered like the chapter. Now I would like to use autoref with that. But it does not work like it is described here () with aliascnt. So how can I get that?  \documentclass[ngerman,halfparskip,12pt,pointednumbers]{scrreprt} \usepackage{babel} \usepackage[utf8]{inputenc}  \usepackage[T1]{fontenc}  \usepackage{amsmath,amsfonts,amssymb,amsthm,bbm} \usepackage{hyperref} \newtheoremstyle{absatz}     {17pt}{10pt}{}{-1pt}{\scshape\bfseries}{.}{\newline}{}  \theoremstyle{absatz}  \newtheorem{satz}{Satz}[chapter] \newtheorem*{satz*}{Satz} \newtheorem{lemma}[satz]{Lemma} \newtheorem{corollar}[satz]{Korollar}   %\renewcommand*{\theoremautorefname}{Satz} \begin{document} \begin{satz} \label{Satz} text text theorem \end{satz}   In \autoref{Satz} we have shown... \end{document}


Adam, Bertrand, and Carissa toss a coin in sequence until one person wins by tossing the first head.  If the coin is fair, find the probability that Adam wins.  Can somebody tell me if I'm on the right track?  Adam can win on the first round if he rolls a head. Or he can win on the second round if all three of them roll tails and then he rolls a head. Or he can win on the third round if they roll tails six times and then he rolls a head.  P(Adam wins) $= .5 + .5^4 + .5^7 + \dots + .5^{3n-2}$ where $n=$ number of rounds.  Thoughts? Should I be getting a numeric answer here...?

Problem: Players A,B and C toss a fair coin in order, the first to throw a head wins what are their respective chances of winning?  Attempt: Let X = event that A throws a head on the first toss, and Y = event that B throws a head on first toss, similarly let Z = event that C throws a head on first toss.  Then there are eight different triple for tossing a coin.  S = {HHH, HHT, HTH, THH, HTT, THT, TTH, TTT}   where H is a head, and T is a tail.  Can anyone please help me? I don't know how to continue. Any feedback/help would be really appreciated. Thank you.


The original problem is that I can't install new apps because of problem of unmet dependecies. I have tried almost all the solutions in this , and non of them worked, so I am completely desperate!  Is there is a 100% guaranteed method to solve this problem?

I was trying to install Lightworks 11.5.1 (amd64) on Ubuntu 14.04(amd64) but there's a notice: Dependency is not satisfiable: libtiff4. Is there anyway to solve this dependency issue?  Thanks in advance.


Why weren't Hermione and Ron allowed in The Three Broomsticks? I know they were underage but Hogwarts students went in all the time. So why can't Hermione and Ron go into The Three Broomsticks?

In Harry Potter and the Prisoner of Azkaban (film), why were Ron and Hermione kept from entering the Three Broomsticks by the shrunken heads for being underage, when Hogwarts students went in there all the time?


I get that PCG is cool or whatever, but 7/16 seems a bit silly    Can we flat limit the number of times a Stack appears in HNQ instead of pulling from the list of popular questions without prejudice? I don't care how interesting it is, imo more than two or three from each site gets to be excessive.  (This screenshot was taken from electronics.stackexchange if that makes a difference, which I doubt)

I was recently browsing through the Hot Network Questions and spotting a weird pattern with the frequency of the sites. So I decided to tally up the results and what I found was not reassuring. These are the sites with more than two questions in the Hot Network Questions and the total questions they had:    => 11  => 6  => 6  => 5  => 4  => 4  => 4  => 3  => 3  => 3  => 3   The bottom of this seems OK but the top 3 are a little alarming. Especially the Code Golf one. I think that you can agree that 11 in the top questions is a little much.  Some of you will surely comment with "Clearly they have a lot of top quality questions". But that isn't true. Or at least it isn't the reason that they have this many. The reason is quite simple: code golf is a competition and so it sure to attract more answers and views than a regular question.  Therefore, I am suggesting that we change the way that the HNQ bot checks for questions. The bot should only promote, at maximum, 5 questions to the HNQ list. I have seen this pattern happen week after week, where code golf takes at least 10 of the HNQs. If we change the algorithm, more questions from less populous sites will be able to gain recognition, allowing them to gain more users and thus expand.  If a site has reached the 5 questions and another question becomes incredibly popular, then the lowest ranking HNQ from that site is removed and the new one replaces it.  Or, for an alternative option, see   What do you think? Any questions?


I'm somewhat new to Ubuntu. I have set my laptop up with a dual boot win8/ubuntu 12.04 each with their own partition and a third empty data partition with the intention of working on files between the two operating systems. After copying some files to the data partition in Ubuntu and then rebooting into a hibernating windows 8 the files had disappeared. I tried repairing the file system in windows 8 and the folder containing the files reappeared however the files themselves are no longer there.  How do I start going about diagnosing this problem? It's critical for me that the files on the data partition are stable, should I consider not using ntfs and forget sharing the files between the two operating systems?

I have 3 partitions: one for Windows 7 (ntfs), one for Ubuntu (ext4) and one just for data (ntfs so both operating systems can see them).  My problem is that I had stored some files on the data partition using Ubuntu and when I booted Windows 7 all that data was gone! After that I couldn't find the files even when using Ubuntu.  My files were simply GONE :(  Is there something I can do in Ubuntu or is it just windows problem?


I have an application to which I gave access to photos several years ago. Now I want to prevent the application from accessing photos, but the application is missing in Settings -> Privacy -> Photo. If I reinstall it, it immediately has access to the photos and does not ask for permission. Updating to newest iOS 14.6 and resetting Settings -> General -> Reset -> Reset Location and Privacy doesn't help.

I have downloaded a game from the App Store onto my iPhone. My understanding is that apps need to ask for, and be granted or denied,  permission to access iCloud, Photo gallery etc.  But in this game, there is an option to change the profile picture, and when I tap on it, it accesses my Photo gallery and I can change the profile picture from images in my gallery.  In Settings, I don’t see that there is any Photo gallery access permission for this app.  What exactly is happening in the background? Does iPhone treat game apps different from normal apps?  The app in question is a game called .


I have a large word-frequency matrix (~6m unique words X ~4k documents) and I'm trying to use truncated singular value decomposition (SVD) to project it onto a matrix with fewer dimensions. I know how to get to $[U_{k}, S_{k}, V_{k}']$, but I don't know what to do then.  Each tutorial I find gives me a different answer. , for instance, I'm told to retain only the first $k$ rows of $S_{k}$ and $V_{k}'$ and then multiply $S_{k}V_{k}'$. In the scikit-learn implementation, however, they do it by multiplying $U_{k}S_{k}'$ ( and ). (The  as source doesn't say anything about that.) In  they suggest $X'U_{k}$ instead (though they are talking about PCA, so maybe that doesn't apply here). Other answers haven't helped (, for instance, they say we need to apply truncated SVD to the reduced matrix - which doesn't sound right, we use truncated SVD precisely to get to the reduced matrix, no?).  So, bottom line: how do I go from $[U_{k}, S_{k}, V_{k}']$ to a reduced data matrix? Which of the above formulas is the correct one (and why)?  Just to be clear: I'm not looking to reduce rank only (that I can do by multiplying $U_{k}S_{k}V_{k}'$ but it gives me the exact same dimensions I had before, which doesn't help me); I want to reduce the actual dimensions of the data matrix.

My original data has many more columns (features) than rows (users). I am trying to reduce the features of my SVD (I need all of the rows). I found one method of doing so in a book called "Machine Learning in Action" but I don't think it will work for the data I am using.  The method is as follows. Define SVD as $$A = USV^\top.$$  Set an optimization threshold (i.e., 90%). Calculate the total sum of the squares of the diagonal $S$ matrix. Calculate how many $S$ values it takes to reach 90% of the total sum of squares. So if that turns out to be 100 $S$ values, then I would take the first 100 columns of the $U$ matrix, first 100 rows of the $V^\top$ matrix, and a $100\times 100$ square matrix out of the $S$ matrix. I would then calculate $A = USV^\top$ using the reduced matrices.  However, this method does not target the columns of my original data, since the dimensions of the resulting $A$ matrix are the same as before. How would I target the columns of my original matrix?


I can't find my house. It keeps taking me to something else I have done, but I can't find my mansion (my house) that I am working on. I really need to finish it before my friend comes over this weekend. What do I do?

I wandered too far to go look for sheep and now I'm on a completely different island.  How do I find my way back to my house?


I try to open and convert to shape a KMZ with Qgis, but impossible ! When I open it, I have this :    I select "Vigne" with 35 entities then OK. But there isn't entity displayed. In layer panel I have this weird icon.    So I decide to save it in shape, maybe it will work... But Qgis return me this message :    Somebody have an idea, how to read and convert this kind of KMZ ?

I am trying to convert a KML file to Shapefile using GDAL (ogr2ogr). Regular KML files convert fine but KML files containing MultiGeometry features (eg: Geometry containing both Point and Polygon) do not get transformed.   The output is simply a blank shapefile containing no shapes or attributes.  I have tried this command:  ogr2ogr -overwrite -f "ESRI Shapefile" -where OGR_GEOMETRY='MultiGeometry' <ouputfolder> <input kml>   For an example, KML file which has MultiGeometry, you can see the us_states.kml hosted by Google.    Other info: I am using 'GDAL 1.10.1, released 2013/08/26' for windows.


I'm looking for a method to change the content of an alertbox in beamer when the user moves to the next frame.  A solution is of course to generate two frames:  \documentclass{beamer} \begin{document} \begin{frame} \begin{alertblock}{Foo} Bar1 \end{alertblock} \end{frame} \begin{frame} \begin{alertblock}{Foo} This is a very long text that should be displayed on two or more lines, as a result, the alertblock will enlarge and thus cause the audience to focus more on the box than the content that is of course the important part of the presentation. \end{alertblock} \end{frame} \end{document}   The problem with this approach is however that if Bar2 has not the same vertical span width as Bar1, the box is repositioned resulting in an ugly visual effect.  As a result in the first slide, an alertblock is displayed containing Bar1 but already has the size to show This is a very..., in the second slide This is a very... is displayed starting at the top-left of the alertblock.

Sometimes I want an element on a frame to change in steps. I do this by  \only<2>{   ...   }   \only<3>{   ...   }     etc.  But this causes the frame to jump due to different sizes of the included content. How can this be avoided?


I have a friend in Moscow who has paid for her trip to Australia.She has claimed that 2700 USD is required by the authorities (30 USD / day for a 90 day tourist visa) to support herself.  Now she wants to borrow this money from me. Is the proof of funds a legitimate requirement for Russian citizens? She claims to have gone through an agency.

My girlfriend is Russian. Last night we tried to fly her to the US on a valid tourist visa. She was stopped at DME and told she would be required to have $2700 USD to get back home immediately even though she had a return ticket. She said this was an "unwritten" rule because of the nonsense i keep seeing on CNN , Anybody else know anything? She is literally trapped and scared to death.


This question has been bugging me for a while. Suppose that $H$ is a subgroup of $G$ such that $Ha\not=Hb$ implies that $aH\not =bH$. I need to show that $gHg^{-1}\subset H$.(I don't mean a proper subset, just subset)  Now, take $x\in gHg^{-1}$. Suppose it is not in $H$. Then $x=ghg^{-1}$ for some $h$. As $x\not \in H$, $Hx\not=H$ whih implies $xH\not=H$ but this doesn't seem to be a terribly bright application of the given condition.(I could have got it using $x\not \in H$) Can someone give me a hint to the solution?

If $H$ be a subgroup of a group $G$  such that $Ha \not=Hb$ implies that $aH\not=bH$.Then how can I show that $gHg^{-1}\subset H$  $\forall$ $g\in G$?  I do not think I have made any progress.However, this is what I have done: For any $h\in H$,$(ghg^{-1})(gh^{-1}g^{-1})=e$ where $e$ is the identity element of the group $G$.  And for $h,k\in H$, $(ghg^{-1})(gkg^{-1})=g(hk)g^{-1}$ which is in $gHg^{-1}$ as $hk\in H$. Thus $gHg^{-1}$ is a group.  I do not think I am getting anywhere.


Before render:    After render:    The render is set to blender game. How do I fix this?    When I want add a material for a text, in first step I'm selected text then set a material color on diffuse option (like green color) for that:    but in the rendering time, this problem is occurred:    This problem only occurs to texts.

I want to change the color of some text in my game. I've tried adding materials, but whenever I press P to play the game, the text stays the same white color. Any ideas?


Alright, so I just installed Ubuntu and I'm new to the Linux community in general so this might seem a bit obvious to most of you, but how do repositories work? I know that a repository is like a server that has a bunch of packages that you can install from but I'm still confused on many aspects of this concept, here are a few of them:  What is apt. I did some googling and its a command utility. So is it just a piece of software for handling repositories? What is the difference between apt and apt-get? There seems to this "Ubuntu software center", which repository is that? Is it like Ubuntu's official repository? Or is it a collection of all the repositories on your computer? How do you search for a package without using the Ubuntu software center (if it's even possible)? When you use apt for installing packages from a third party repository, it doesn't seem like you need to specify which repository. Thus it seems like when you add a repository, it all gets added to this one big abstract repository. Won't that cause name conflicts? When you want to add a repository, it seems that you can do something like this, sudo add-apt-repository ppa:webupd8team/java How does apt locate that repository? There doesn't seem to be a URL of any sort.  I know this is a lot of questions but if you could answer even 1 or 2 that'd be really helpful. Thanks in advance :)

I read about the new fancy progress bar which was added to apt 1.0 in  and how to enable it . However on running sudo apt-get update, I did not see the fancy progress bars. On reading the second link again, the solution explicitly requires you to use sudo apt update.  Hence my question is the difference between apt and apt-get. I thought they were one and the same.


I traveled back to China using my Chinese passport for summer break, when I’m travelling back to Canada, I’m using my Chinese passport booking a flight to Seattle (I have a Visa) that is stopping in Canada, would I be able to enter Canada using my Canadian passport even if China doesn’t allow dual citizenship?

I am a citizen of two different countries, and have two passports.  How should I use my passports when traveling?


Becuase I used google + as a sign up, now my name brings up my stack overflow user account when companies search my first name. This is really annoying since I'm job hunting.

How can I delete my Stack Exchange account(s)? Also,  What happens to my content? Can I request it be deleted as well? What if I'm suspended, rate-limited, or banned from posting questions or answers? What will happen to my votes? Will other users be impacted? Why wasn't my account deleted immediately after the timer expiring? What will happen to my pending bounties and close, reopen, delete, or undelete votes? I want my account deleted on all Stack Exchange sites. How do I do this? Will my profile on chat be removed once I delete my site account?   For more information, see "" in the .


I'm using  for Lyx. However, I couldn't figure out how to globally reset the chapter number after the start of a new part. This is how the TOC looks right now:   Part 1   1 Chapter 1 Chapter  Part 2   3 Chapter    But I want it to look like this:   Part 1   1 Chapter 1 Chapter  Part 2   1 Chapter    Every help is appreciated! Thanks a lot in advance!

To get the output Toc or pdf bookmark below:   Part I     Chapter I     Chapter II Part II     Chapter I     Chapter II   I need to reset the chapter counter. I google and get one method.   \makeatletter \@addtoreset{chapter}{part} \makeatother   Yes, It can output like this. But hyperref package can not link to right target for chapters after chapter I. That is said page ref link broken.  I like to define all style in style file. the mini-document:   \documentclass[]{book} \usepackage[]{hyperref} \usepackage{mini} % my own style file  \begin{document} \tableofcontents \part{Test} \chapter{One} \chapter{Two} \part{Test} \chapter{Three} \chapter{Four} \end{document}    and the mini style file:   \renewcommand\part{%   \if@openright     \cleardoublepage   \else     \clearpage   \fi \setcounter{chapter}{0}} % I reset manually here.


I recently purchased Minecraft for my Xbox and I have been playing through it.  I've started looking through the Minecraft wiki and have noticed that some things aren't in the Xbox version. However, I haven't been able to find a comprehensive list of everything that's not in the Xbox version. What elements of Minecraft Java Edition are not in the Xbox 360 version?

What differences does the Xbox 360 version of Minecraft have compared to playing on the PC? To clarify - I'm concerned more about the differences exclusive to each platform, not just differences of features that will probably be added in future updates (for example, crafting). Otherwise, I feel this question could be compared to "What is the difference between Minecraft version x and version y", which isn't what I'm asking.


I am trying to install older version of Google Chrome. I am able to install older versions on my machine, but as soon as installation processes are getting completed, it will start updating the latest version automatically. This stops me to do my work.  Can anyone suggest me how to stop this auto updating process in chrome.  Thanks, Sourabh

I have downloaded the offline (consumer, i.e. not msi package) installer for Google Chrome. But when I run it, it tries to contact a Google server to check for a newer version. If it finds it, it will download that first, and then install that version. It doesn't use the version that is already there, as part of the EXE file. For me, that defeats the point of having an offline installer. I keep a repository of all the free and purchased software locally, so that I can install them quickly whenever I need to. But as more and more people get access to broadband Internet connections, many developers and companies are pushing for offline installers with new releases. Many software titles, like Google Chrome, are almost exclusively distributed with online installers.  File name: ChromeStandaloneSetup.exe File version: 1.3.21.115 Size: 36.6 MB (38 416 368 bytes) SHA-1: 2393BAB7F408DC8D30F039FCA5D6B45600A0C4E7   How do I install Chrome as is, without automatically checking for and getting a newer version?  Will  work with Chrome installer? Is there a switch to disable version check when running the installer?  Update:  The "duplicate" question linked to below points out File Hippo as a possible repository where you one can get previous versions of Chrome. They do have a healthy listing of pretty much every single Chrome version ever released on Windows, both beta, dev and stable versions. Unfortunately they don't host the installer files, they only redirect to Google servers for downloads, which only spits out the installers for the latest versions of Chrome. It's not just File Hippo, I also tried downloading an older version of Chrome from CNET Downloads, and they too just redirect you to Google servers for download.  For whatever the reason (security related probably), Google doesn't like anyone to install an older version of Chrome on any system. Apparently not even your common source for downloading an older version of a software, like the CNET Downloads, not even they are allowed to host the Chrome installer files on their own servers. The redirects to Google is probably dictated by Google.     Google is a dictator!   They don't even allow full standalone offline installers to be installed as is, without checking for newer version. I tried running the installer from cmd with some of the command line switches used for Chromium. I only ended up with errors.    The business oriented msi installer (GoogleChromeStandaloneEnterprise.msi) might have some additional command line options you can use, but I wouldn't know if there is one that disables the check for a newer version. I have yet to find a complete list of switches you can use. The only one I've found so far is /update but that only does the opposite thing. So I'll give up here and go back to the trusty Firefox.


I am learning Ubuntu and I am installing Redis. When I use the following guide, an older version of Redis is installed. 4.0.x    According to redis.io, the latest stable version is 5.0.5. Why does apt install install a 4.0.x version and not the latest 5.0.5 version?  I'm using Ubuntu 18.04.  Thanks!

Why are packages in the official Ubuntu repositories older than the latest (upstream) versions from Debian Sid, PPAs, the authors, etc.?


Is there a way to find out the percentile (in the reputation distribution) of a person's reputation on a specific site? The actual meaning of, say, 5k reputation, is different depending on the specific site, but the percentile (e.g., 50% - median - vs 5% - i.e., 95% of users have smaller reputation) should be more comparable. EDIT: The information is almost available as  but should be as percent in addition to rank (being in top 1,000 out of 10k is very different than 1,000 out of 100k). Also, I think the percentile should be appended to raw reputation everywhere, i.e., instead of foo 1234 it should be foo 1234 (33%) if 33% of users on the site have reputation over 33%.

At the user's info, there is a percentile status like     top 3% this year   Is there a way how to check other (week, month, quarter, all time) periods percentile?


Let $f$ be the function on $[0, 1]$ given by:  $$f(x) = \left\{\begin{array}{ll} 1 & : x \neq \frac{1}{2}\\\\ 2 & : x = \frac{1}{2}\end{array} \right.$$  Prove that $f$ is Riemann integrable and compute $\int_0^1 f(x)\,\mathrm dx$.  Hint: for each $\epsilon > 0$, find a partition $P$ so that $U_P (f) − L_P(f) \leq \epsilon$.  So I understand that I have to show that $U_P (f ) = L_P(f )$ to show that it is integrable, but I have no idea where to start. What partition do I pick and how do I even come about picking it?  Also as far as the integral, I figure that it is 1, although I'm not sure if I am right. Since it is a single point ($x = \frac{1}{2} $) where the function is not uniformly continuous, does it change the area as a whole?

Prove that if the real-valued function $f$ on the interval $[a,b]$ is bounded and is continuous except at a finite number of points then $\int^1_0f(x)dx$ exists.   I know that I can break up the interval $[a,b]$ into subintervals where each subinterval has one discontinuity point. Then if $f$ is integrable on each subinterval then it is integrable on $[a,b]$. So if I let $c$ be my point of discontinuity in the subinterval $[a_1,b_1]\subset [a,b]$, where $c\in[a_1,b_1]$. Then how can I show this subinterval is integrable?


From time to time, although not so commonly, I see $A \supset B$ written with seemingly the same meaning as $A \Rightarrow B$.  Ex. in , on page 8.     A proof of $A \supset B$ is a method which transforms   a proof of $A$ to a proof of $B$.   This suggest $A \supset B$ means the same as $A \Rightarrow B$, isn't it?  $A \Rightarrow B$ means: whenever $A$ holds, then $B$ holds. However, this also means $B$ may holds when $A$ do not. Which in turn means the set of the cases where $A$ holds is a subset of the set of the cases where $B$ holds. Is this OK? If that's OK, $A \Rightarrow B$ should be written as $A \subset B$ instead of $A \supset B$.  Why is this not so? Or am I wrong in some way? If I'm wrong, where am I so?  Edit: oops, duplicate of this one:  . Sorry.

I saw that a use for the notation $p\supset q$ instead of $p\implies q$ that got me a bit confused.  One occurrences is in this .  It seems to me opposite than what it should be, let me explain what I mean:  If $A,B$ are sets s.t $A\subset B$, $p$ is for $x\in A$, and $q$ is for $x\in B$ then we can identify (in some way) $$A\text{ with }p$$ $$B\text{ with }q$$  We have it that $p\implies q$, since $A\subset B$, but in the above notation we have $q\subset p$ which to me looks like $B\subset A$  which is the opposite of what we wanted to express.  Can someone please explain to me the logic behind this notation ?


When you paste an url in a question or answer (i.e. a post), its link text is automatically replaced with the title of linked-to question, like so:   However, this is not done for comments. When you paste a link to a relevant question (perhaps even only the url) into the comment box, it will be displayed verbatim. This is especially tiresome for recurring c++-faq question-link comments. These questions have usually fairly well-curated titles that say enough on their own, but I have to Copy-Paste both the url and the title and manually [Ctrl-V](Ctrl-V) them.  What is the reason for this? Or am I using the interface wrong?

In questions, links get converted into question titles (see )  Can the same functionality be added to comments?


Determine the convergence of the following series: $$\sum_{n\ge2}^{ }\ln\left(1-\frac{1}{n^{2}}\right)$$  I tried several convergence test like $n$th term test,ratio test,Abel's test,Dirichlet's test,Schlömilch's Generalizatio,but neither does work. But I used the identity: $$\prod_{n\ge0}^{ }\frac{\left(n+a\right)\left(n+b\right)}{\left(n+c\right)\left(n+d\right)}\tag{$a,b,c,d \in \mathbb R$}=\frac{\Gamma(c)\Gamma(d) }{ \Gamma(a)\Gamma(b)}$$ For $a+b=c+d$. Notice that: $$\prod_{n\ge2}^{ }\left(1-\frac{1}{n^{2}}\right)=\prod_{n\ge0}^{ }\frac{\left(n+1\right)\left(n+3\right)}{\left(n+2\right)\left(n+2\right)}=\frac{1}{2}$$ The sum can be rewritten as: $$\sum_{n\ge2}^{ }\ln\left(1-\frac{1}{n^{2}}\right)=\ln\left(\prod_{n\ge2}^{ }\left(1-\frac{1}{n^{2}}\right)\right)=\ln\left(\frac{1}{2}\right)=-\ln\left(2\right)$$ Wich is between $-1$ and $0$. I have two questions: Then how prove the series is convergent without directly calculating that?

How to prove that the series $$\sum_{n\geq 2}\log\left(1-\frac{1}{n^2}\right)$$ is convergent? What about finding the sum?  My attempt: $$\ln (1-1/n^2)= \ln(n-1) -2\ln n + \ln(n+1)$$ The term in the log is decreasing so I get the feeling that the series converges but confused how to prove this and also find the sum.


I'm trying to write an alias to list all the files in a directory ending in JP(E)G in its various forms. The ones I'm looking for it to recognise are .jpg .JPG .jpeg and .JPEG.  Is there a form of ls (or ls in combination with another command, such as find or grep) that will do this?

I would like to list all files matching a certain pattern while ignoring the case.  For example, I run the following commands:  ls *abc*   I want to see all the files that have "abc" as a part of the file name, ignoring the case, like  -rw-r--r-- 1 mtk mtk 0 Sep 21 08:12 file1abc.txt -rw-r--r-- 1 mtk mtk 0 Sep 21 08:12 file2ABC.txt   Note  I have searched the man page for case, but couldn't find anything.


I'm trying to pass data from one javafx controller to another by calling a function in the new controller but every time I do so I just get a load of errors and mostly NullPointerException and have no idea why.  // admin controller public class AdminController implements Initializable{      @FXML      private Button newTermButton;      private String error;      private Stage stage;      @Override     public void initialize(URL location, ResourceBundle resources){     }      //buttons     @FXML      public void newTermButton() throws IOException {          FXMLLoader loader = new FXMLLoader();          loader.setLocation(getClass().getResource("../term/Term.fxml"));          try {             loader.load();         } catch (IOException ex) {             // error         }          TermController tmp = loader.getController();          //error with this line         tmp.newTerm();          javafx.scene.Parent p = loader.getRoot();         Stage stage = new Stage();         stage.setScene(new Scene(p));          stage.showAndWait();      } }     // term controller public class TermController implements Initializable{      @FXML      private TextField termId;     @FXML      private TextField name;      @FXML      private DatePicker sDate;     @FXML      private DatePicker eDate;       public void loadTerm(int i) {         System.out.println("load term : " + i);     }      public void newTerm() {         System.out.println("new term");     }      @Override     public void initialize(URL arg0, ResourceBundle arg1) {         // TODO Auto-generated method stub      }  }   I'm trying to just run a function in the TermController from the Admincontroller so the controller will know weather to load a term from my data file or create a new one.

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


I would like to send a number to file.txt as a temporary storage for another variable, which can easily be done. I just can't work out what to use to extract the first line of file.txt (which is a number ranging 1-100000) and set it as a %variable% in my running batch script.  So by the end of it I should be able to do echo %first-line-of-file.txt% and it'll print x  Any ideas on how to make this work is much appreciated

How can I read the first line from a text file using a Windows batch file? Since the file is large I only want to deal with the first line.


I have a basement office that I intend to put a drop ceiling in. I was also planning to use the can lights that rest on the drop ceiling track itself rather than between the floor joists above. How would I rough in these can lights in this scenario since the drop ceiling supports won't exist until after drywall is up? Also, are there better alternatives for lighting?

I am installing a drop ceiling with pot lights as part of remodeling a portion of my basement. Since I am refinishing the entire room (newly framed walls), it seems like I have a catch 22:   I need to get the electrical rough-in done before I put up drywall (including the wiring to the pot lighting fixtures in the drop-ceiling) However, I have always seen drop ceilings installed after the drywall is up, which means I cannot mount the pot lights in the ceiling/wire for them unless I mount the grid (or some portion of it) for the drop ceiling first.   Can I wire up a portion of the grid for the suspended ceiling before drywalling and leave gaps around the edges slightly bigger (~1/8" - e.g. 3/4" gap for 5/8" cement board) than required to insert drywall, or is this a ludicrous suggestion?  Or, is the wiring for pot lights in this situation typically addressed as part of the final inspection? I was not planning on having any additional junction boxes between the panel and the pot lights (all splices to supply multiple lights are supposed to just be inside of the boxes on the pot lights per my submitted plans). Since a portion of the wire run from the breaker panel to the pot lights will be concealed by dry wall for another room (I am finishing the other room at the same time under the same permit) which means the cable would be run from the panel and dangling near where the pot light will eventually be mounted for the rough-in inspection in this case.  I plan on calling my inspector to see what is acceptable, but what is typical practice in this situation?


I'm reading  by Rokach, and i've got to a chapter about ensemble methods (using multiple classifiers) and this is where I can't wrap my head around this concept of Plurality Voting (PV).    $$\operatorname{class}(x) = \operatorname{argmax} \left (\sum g(y_k(x), c_i)  \right)$$  Where $$g(y_k(x), c_i) = \begin{cases}1 &\text{if } y = c\\                                 0 &\text{if } y \neq c\end{cases}$$  Most of the other metrics in the chapter weight classifiers, yet this seems to just essentially pick the one which has the highest chance of returning the class you want.  Which seems useless? If thats the case how would this be helpful?

I'm reading . Then I'm not able to figure out the difference between hard voting and soft voting in context to ensemble based methods.  I quote descriptions of them from the book. The first two images from the top are description for hard voting, and last one is for soft voting.        In my view hard voting is majority decision, but I don't understand soft voting and the reason why soft voting is better than hard voting. Would anyone teach me these?


Let a family have two children. It is known that one of the children is a boy. What is the probability that both the children are boys. So for this we build the sample space $S=\{(b,b)(b,g)(g,g)\}$ Let our event E be the case where both children are boys $E=\{ (b,b) \}$ Let the conditional be F $F=\{(b,g),(b,b)\}$ Hence $P(E|F)=\frac{P(E\cap F)}{P(F)}=\frac{1/3}{2/3}=\frac{1}{2}$ But the answer in my book is given as $\frac{1}{3}$ and I can't seem to understand why.

In a family with two children, what are the chances, if one of the children is a girl, that both children are girls?  I just dipped into a book, The Drunkard's Walk - How Randomness Rules Our Lives, by Leonard Mlodinow, Vintage Books, 2008. On p.107 Mlodinow says the chances are 1 in 3.   It seems obvious to me that the chances are 1 in 2. Am I correct? Is this not exactly analogous to having a bowl with an infinite number of marbles, half black and half red? Without looking I draw out a black marble. The probability of the second marble I draw being black is 1/2.


I read in an online flash card that the command is:  pkill -u bob $(pgrep -u bob)   However, I think this is wrong. I think it's saying:     Kill all the processed owned by bob, and 4572\n4600   Because:  [bob@localhost ~]$ pgrep -u bob 4572 4600   Also, it gives an error:  [bob@localhost ~]$ pkill -u bob $(pgrep -u bob) pkill: only one pattern can be provided Try `pkill --help' for more information.   Which makes sense because you can't have newlines in usernames, right?  I think the command should only be:  pkill -u bob   To "kill all processes owned by bob"  While the command:  pgreg -u bob    Gives "all processes owned by bob"  I'm wondering:   Am I uses the right commands as intended? Is my analysis of the incorrect way accurate?

How to kill all process of one user? When I make ps aux I obtain a list of process with several users, and I want to kill all process of user name1, for example. What's a command to do that in Ubuntu?


I think this is a short story, I read it 30-40 years ago. A lone astronaut on a space station wakes to find someone bashing on his bedroom door. It is himself from tomorrow, offering to help him repair the space station, which is a two-person job. As the space station travels through the wormhole (I think that term is used), it becomes crowded with other time versions of himself. Does anyone remember the title and/or author?

Okay, similar questions to this have been asked before, but not about the particular short story I am trying to find.  It was in an anthology of short sci fi stories, possibly award winning ones or at least someone's compilation of favourites. (I think)   It was a long time ago, maybe 1970s or 80s, so the story could date back to even the 1960s for all I know, but probably the 1970s.  It was the funniest story about time travel where a person meets incarnations of himself, that I have ever read. It was either derivative of 'By His Bootstraps' or the other way around, but my recollection is that this story was funnier.  Maybe my memory is playing tricks on me and it WAS 'By His Bootsraps', but I am almost certain that it wasn't, because when I read that recently it seemed unfamiliar and not as funny.  In the one I am trying to recall, the guy is also bemused and irritated by the behaviour of other incarnations of himself, like the Heinlen story, but the repartee between versions of himself and his extreme frustration is much more hilarious.  I have a vague recollection that he is in a spaceship during the story, but not absolutely sure. There seemed to be a lot of clambering around, ladders, bulkheads, etc, unlike the Heinlen story.  I'm almost certain it isn't any of the commonly suggested stories and I'm quite sure it wasn't a short film where he shoots his older self, or a full length novel. Someone will have read it and (un)remembered it fondly like me, I feel sure!


Is there a way to type special unicode characters, or more specifically foreign currency sumbols, on an iPhone or iPad?  I mean symbols like ¥ (Yen), ฿ (Bitcoin or Thai Baht), ₩ (Korean Won) etc.  I'm just using a normal english iOS 9. How can I type those e.g. when writing an email or Telegram message or when submitting info on a website?

How can I insert symbols like copyright or degree symbols?


I am thinking in uploading my Master's thesis to arXiv, by the moment I would count with the endorsement of my supervisor, nevertheless I will not follow an academic career, so I will not keep my university mail. Therefore,  I am wondering if I could register in arXiv with a personal personal email. Is it allowed by arXiv?

The question is similar to  but in addition I would like to ask the following: Don't  I need to change my email address if I am no longer affiliated to an institution?  Won't a new mail of the form www.someone@hotmail.com  make me lose ownership of all my papers and then need endorsement from another arXiv user?    Thanks in advance!


Community edited  and changed valid links to invalid, and left strange comment.  Is there any reason for it?

Recently the  bot was ran on Ask Ubuntu Meta to migrate all the MSO links to MSE links. But in the process, the bot converted all the posts written in markdown to HTML. An example preview:    This bot doesn't like markdown and I want it to be handed a time-bound suspension. It has vandalized all the posts that were written in markdown to convert to a different language. Moreover, the bot has edited 289 posts on our Meta in a span of less than a second.  In addition to the suspension, it would be better if all the posts can be re-converted to markdown.


Can someone suggest me a good book on cryptography with a lot of solved examples.

I want to self-study some abstract algebra and cryptography during the summer, so what are some of books that are suitable for self-study? I have very limited background in algebra and none in cryptography, and like to learn by examples. Also, please let me know if there are any books on these subjects with solutions to most of the exercises, so I can check on myself. (I saw 's post about good algebra books, but I would like to focus more on those with good exercises and detailed solutions.)  All suggestions are welcome! Thank you!!


I have some trouble understanding the concept of a covariance matrix. For instance, I'm going over this question that says: assume that we have U1, U2 and U3 as independent zero-mean, unit-variance Gaussian random variables. Furthermore, we have X = U1, Y = U1 + U2, and Z = U1 + U2 + U3. We're asked to find the covariance matrix for (X,Y,Z).  I just require some guidance/hints on how to solve this sort of a problem. And I'd really appreciate any help on this matter.

I try to understand and visualize myself covariance matrix. Supposing I have a matrix A = [ 2 3 4; 5 5 6 ], how do I calculate its covariance matrix, and what is its practical meaning? (All I was able to understand by now is that on the diagonal of the covariance matrix, variances for particular variables are placed, and on the upper and lower fields correlations between those variables.)


I'm frequently transferring files and operating programs via ssh, and often from home. The machine I usually work on is a desktop at work that I cannot ssh to directly unless I'm already connected to the department network. Thus if I'm at home, I must ssh to my department's network first and then to my desktop, ie  ssh username@departmentnetwork and then ssh username@desktop-departmentnetwork  This setup means that if I am to transfer files from home, I must scp the files to my drive on the department network, ssh in to the department network, then scp the files again to my desktop.  Is there a way to use any or all of ssh, scp, and sshfs to connect to a 'network within a network'?

To get to my machine in my office, at the moment I am doing this:  me@home:~$ ssh unix.university.com me@unix:~$ ssh unix.department.univeristy.com me@unix.department:~$ ssh office-machine.department.university.com me@office-machine:~$ echo "This is very annoying"   Is there an easy way of automating this process, perhaps a single command that I can use at my end?


Consider the subset of $\mathbb{R}^2$:   $$T=\{(x,y):x\notin \mathbb{Q} \text{ or } y \notin \mathbb{Q}\}$$      Is $T$ open, closed, compact, connected (under the standard Euclidean topology)?   First, $cl(T)=\mathbb{R}^2$ and hence $T$ is not closed.  Then since $\mathbb{Q}$ is dense in $\mathbb{R}$, it's not possible to find an open neighborhood $U$ of $(x,y)\in T$ such that $U\subset T$. Hence $T$ is not open.  Consider the open cover $\{B(x,1)\cap T: x\notin \mathbb{Q}\}$, which is the union of open balls centered at irrational $x$ with radius $1$. Then $T$ is not compact.  Is $T$ connected? $T$ is the $xy-$plane after deleting all rational points. Hence I think $T$ is more than connected: $T$ is path-connected.

Here's a question that I share:  Show that if $D$ is a countable subset of $\mathbb R^2$ (provided with its usual topology) then $X=\mathbb R^2 \backslash D $ is arcwise connected.


I have a sentence: Happiness is drinking a glass of champagne on a hot summer afternoon. So I'm thinking if we want to say the same about night do we have at night or on [article] night? I know we say in (the afternoon / the evening / the night) when we mean 'during this period of time'. Correct? But what is the difference between on and at? Could we use articles with on\at and night?

I have found the following usage of "on", "at" and "in" on the internet. Is there any other exception and/or rule for that?  Prepositions of Time Use in for  Months: in April / in September / in that month Seasons: in (the) summer / in (the) winter Years: in 1332 / in 1984 / in that year / in the next year Long Period(s) of Time: in former century / in 90's / in the Ice Age / in the past / in the future  Exceptions: in the morning / in the evening Use at for  Time: at 8 o'clock / at 9:30 / at bedtime / at sunset / at dinnertime / at 5:33:10 AM  Exceptions: at Christmas (= during the Christmas holidays but not necessarily on December 25th) / at Easter  / at noon / at night / at the weekend / at the present time / at the moment Use on for  Days: on Monday / on Friday / on Christmas Day (= on December 25th) / on Easter Sunday / on Independence Day Dates: on February 18th / on her birthday / on 21 March 2015 / on  Notice:  We have in the morning and on Monday but we say on Monday morning, not in Monday morning, and so on. When we say last, next, every, this we do not also use at, in, on: She runs next Tuesday. (not on next Tuesday) / He leaves us every Easter. (not at every Easter) / I See you this evening. (not in this evening) Look at these examples for the combination of times in a sentence: We will meet next week at six o’clock on Monday. / I heard a funny noise at about eleven o’clock last night. / It happened last week at seven o’clock on Monday night.   Look at  as well which says:  This all hints at a coherent metaphor: hours and other short periods of time are places; days are surfaces; months and longer time periods are containers.


This question is in reference to an  I received from a previous .  The answer talks about a cubic polynomial $p(x)$ over a (possibly non-perfect) field $F$ which factors over a splitting field as $p(x) = (x-\alpha)^2(x-\beta)$, where $\alpha$ and $\beta$ are not neccesarily distinct, and we are trying to determine if $\alpha$ and $\beta$ have to be in $F$.  My main hangup is the answer talks about the Galois group of $p(x)$, but Dummit only defines the Galois group of a separable polynomial, and only makes an extension of the definition to inseparable polynomials in the case of polynomials over perfect fields. So what is meant by the Galois group of an inseparable polynomial over a non-perfect field? Is it just the automorphism group of the splitting field $K$ of $p(x)$ over $F$, even if $K/F$ is not Galois?

In my notes, I am given the definition of the Galois group of a polynomial only in the case when the polynomial is separable (if $f$ is a separable polynomial over $K$ with splitting field $L$, then $\mathrm{Gal}(f) = \mathrm{Gal}(L/K)$). This makes sense, since $L$ is a splitting field implies normality, and an extension generated by separable elements is separable, so $L$ is necessarily a Galois extension of $K$.   I should probably tell you that my definition of separable is the one which involves the irreducible factors of the polynomial having distinct roots in a splitting field (I'm aware there's another definition, and that they coincide when defining a separable extension).   When I look around online, I see that the Galois group is defined for any polynomial as the Galois group of its splitting field. Why is the splitting field necessarily Galois?  Thanks


I looked in the online manual, but all I am trying to do for example is set (Cube 1) on layer 1 and take (Cube 2) and put that on layer two but I cannot figure out please help thank you!

I am building a model for a game and have decided to copy part of it into a separate layer. How do I copy one or more objects to a different layer?


I would like to label my figures and tables continuously using S.I, S.II, S.III, etc in the caption of both, figures and tables.  I can change the figure and table caption to S.I, ... by   \renewcommand{\tablename}{S.} \renewcommand{\figurename}{S.} \renewcommand{\thetable}{\Roman{table}} \renewcommand{\thefigure}{\Roman{figure}}   but this still counts figures and tables separately. S.I thus exists twice, once for the first figure and once for the first table.   How can I avoid this? Thank you!

Is there a way to have a List of tables and figures as one list? Currently I have  \listoffigures  \listoftables   which generates two lists and starts a new page for each list. What I want is a list that contains Tables and Figures in the same list, numbered in sequence (i.e. the first table should get the number following the last figure at that point), Babel-compatible and KOMA-Script-compatible if possible (I use both). The example command  \listoffiguresandtables   should create something like     List of Figures and Tables      1.1 A nice picture caption      1.2 Another nice picture caption      2.1 A caption of a cool table    How to do this?


In the episode 6x10 of GOT, Littlefinger speaks with Sansa      after they defeated the Boltons   He talks about his dream and they talk about who should lead the North. There Littlefinger has a line:     A trueborn daughter of Ned and Catelyn Stark born here at Winterfell or a motherless bastard born in the south?   Who does he speak of? In the context he could only mean Jon, because it's either him or Sansa who takes command.     But he talks about a motherless bastard from the south. Could Littlefinger know that Jon is the son of Rhaegar or did he only mean that he was born in the south, assuming that he is the child of Ned and that motherless means that no one knows who Jon's mother is?   Am I just over-interpreting things here, or does he speak of someone completely different?

There are a lot of great theories telling us that Eddard Stark couldn't be the father of Jon Snow, like this one:    But, who could tell the truth about him, who knows this (that is still alive) that could confirm these theories?


This is what I'd like to achive in Xcode/swift:  I want to create a blank "canvas" at a fixed size, ex. 300x300px. I want to add a picture to the canvas and the picture should be zoomable (pinch to zoom) within the boundaries of the canvas.   Finally when the preferred zoom/crop is set, I want to save the crop in the 300x300px size canvas.   Anyone who has a solution to this and is this in any way possible? Greatly appreciated.

I would like to zoom in/out an UIImage object when the user performs the standard pinch action on my application. I'm currently using a UIImageView to display my image, if that detail helps in any way.  I'm trying to figure out how to do this, but no such luck so far.  Any clues?


What is giving me trouble is the phrase     + your Constitution modifier per [class] level after 1st.   Does this simply mean I add my CON modifier once each time I level up, or add my CON modifier a number of times equal to my class level?

I am new to D&D and I'm starting with the 5th edition. I have a question about how many hit points I have for a level. I am confused about the con modifier per level and if it is added to first level.  Let's say my con modifier is +3 and I decide to take 6 instead of rolling the d10 (as a Ranger).   Hit Points at 1st level: 10 + Constitution Modifier Hit Points at Higher Levels: 1d10 (or 6) + your Constitution Modifier per ranger level after 1st.   At first level, my HP is 13. OK. That I understand. At the 2nd level is it 6 + 3 (con. modifier) equal to 9, then added to my first level's HP, for a total of 22? Or is it 6 + 3 (con modifier for first level) + 3 (con modifier for second level) equal to 12? Then is this added to the HP from first level?  If you could give me an example of, say, the first 4 levels of a ranger using the numbers I gave you (6 instead of d10 and +3 as a con modifier), that might make it easier to explain.


I am reading some numbers from a file in C.  For example,  0.00632, 0.02731...  I store these numbers in double type variables.  This is how I read them:  fscanf(fp_ptr, "%lg", &num);   However when I check the value of the num via the watch window of the program I use (Visual Studio Express), I see the values as 0.0063200000000000001, 0.027310000000000001...  Is this normal? How can I read the exact value in the file?

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


Was having some fun with prompt, parseInt and do...while and just stumbled upon the following:  do {     let length = prompt('Enter a number between 8 and 128 (inclusive) for your length.');     length = parseInt(length, 10); } while (length < 8 || length > 128);   Every time I would use the Chrome Developer tools to inspect the value of length during the while execution, I would see a value of 0. I thought there was something up with the radix I had chosen for parseInt but that was not the case.  I noticed that VS Code was complaining that the let length was not being used anywhere. That was odd. Once I removed the variables outside of the loop and declared as separate string and number fields instead, (i.e., let lengthPrompt and let length), everything worked out:  let lengthPrompt; let length;  do {   lengthPrompt = prompt('Length?');   length = parseInt(lengthPrompt, 10); } while (length < 8 || length > 128);   Is this an issue with scope or some other weird JS specific thing I am unaware of.

What is the scope of variables in javascript? Do they have the same scope inside as opposed to outside a function? Or does it even matter? Also, where are the variables stored if they are defined globally?


I have recently started studying graphs and their different traversal algorithms, and can't seem to be able to come up with answers to these two questions. I really need your help, I don't even know where to start.  (a) Prove that every connected graph G=(V,E) has a node v∈V such that removing vv and all its adjacent edges will not disconnect G.  (b) For a given connected graph G=(V,E), design an O(n+m)-time algorithm to find such a node.  I have found some answers , but they still don't make a lot of sense to me because I don't have a lot of experience in the topic.  Thank you so much in advance!

In the city there is a subway. You can get from any station to any other one. How can I prove that if we close one of the stations ( it can be picked),you won't be able to drive through it), we will be able to get from any station to any other one.


In debug mode, I can see what returned from method by moving mouse pointer to "name" variable;  public string GetUserName(int id) {     string name = UserService.GetUserName(id);     return name; }   But I don't want to create a variable to just to see what inside it...  So what is the proper way to debug one line returned method like;  public string GetUserName(int id) {     return UserService.GetUserName(id); }   *Notes    I don't want to use F11 to get inside of GetUserName method. I don't want to use immediate window.

Take the following function:  DataTable go() {     return someTableAdapter.getSomeData(); }   When I set a breakpoint in this function, is there a possibility to inspect the returned value? go() is directly coupled to a datagrid in an .aspx page.  The only way to inspect the returned datatable is to use a temporary variable. However, that's a bit inconvenient. Isn't there another way?


I will be traveling to Tanzania on 10 November 2019 and my transit for two hours in Zurich, Switzerland and will be back on 17th

I found many related questions on this site but I am still not sure about the rules. How can I decide if I need a visa to transit? Schengen members as of May 2021 are as follows:  Austria Belgium Czech Republic Denmark (excluding Greenland and the Faroe Islands - but an open border with the Schengen Area is maintained) Estonia Finland France (excluding overseas departments and collectivities) Germany Greece Hungary Iceland Italy Latvia Liechtenstein Lithuania Luxembourg Malta Netherlands (excluding Aruba, Curaçao, Sint Maarten and the Caribbean Netherlands) Norway (excluding Svalbard) Poland Portugal Slovakia Slovenia Spain (except Ceuta and Melilla) Sweden Switzerland


is there any proof for the Leibniz rule for successive differentiation  $(uv)^{(n)}=\sum\limits_{k=0}^n\binom{k}{n}u^{(n-k)}v^{(k)}$

How do I show through mathematical induction that   \begin{equation} \frac{d^n}{dx^n}[f(x)\cdot g(x)] = \sum_{k = 0}^{n} \binom{n}{k} \frac{d^k}{dx^k} [f(x)] \cdot \frac{d^{n-k}}{dx^{n-k}} [g(x)] \end{equation}  which is the product rule for higher derivatives?


first to all sorry for my english, isn´t me native language and is difficult for me. It´s the first time that i use this forum for that reason.  Now, i´ll try to explain my problem. I need to do multiple bibliographies, one for each chapter, and for it i´m using the package \usepackage[sectionbib]{chapterbib} (I'm using TexnicCenter), and using a file .bib  for each one of them.  After to compilate, in the end of each chapter appears the respective bibliograpy, but in the part of the text where's the cite (\cite{....}), in pdf file (Latex=>PDF) appears [?], even after two or three compilations.  Is the first time that i have this problem, but also is the first time that use \usepackage[sectionbib]{chapterbib}, so think that the problem is there, although the bibliographies are created in each chapter after compilation, means that files .bib are ok and to use \usepackage[sectionbib]{chapterbib} would be right, so i don´t know where is my mistake

I've browsed the forums and found a number of posts that have addressed this issue, but none of the solutions seem to work for me. I have the following script that I just copied from the bibtex home page to get familiar with it. Instead of the citation number I get a question mark. I compile using Latex+Bibtex+Latex+Latex+PDFLatex+ViewPDF just as has been previously suggested and the problem persists.   \documentclass[11pt]{article} \usepackage{cite}  \begin{document}  \title{My Article} \author{Nobody Jr.} \date{Today} \maketitle  Blablabla said Nobody ~\cite{Nobody06}.  \bibliography{mybib} \bibliographystyle{plain} \end{document}   My bibliography (Bib.bbl)  @misc{ Nobody06, author = "Nobody Jr", title = "My Article", year = "2006" }    Looking at previous posts one thing that is concerning is that my .bbl looks empty as shown below. Further, I don't have a .blg  \begin{thebibliography}{}  \end{thebibliography}


I was using Ubuntu 12.04. But today I just made format my system and installed Ubuntu 13.04. I have made copied the archive file (/var/cache/apt/archives) from Ubuntu 12.04 and made paste to 13.04 . After I made the system update by doing commands (sudo apt-get update) terminal. Then after that whatever I am trying to install on my system it is showing error like   Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package package-name   Even I tried to install apache server by using sudo apt-get apache2. It is showing the error like   Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package apache2   So can someone kindly tell me how to solve this issue. Any help and suggestions will be really appreciable. Thanks

Recently I have installed an older version of Ubuntu on my old machine. Whenever I try to install any software, I get an error saying it couldn't be found:  $ sudo apt-get install vlc Reading package lists... Done                Building dependency tree        Reading state information... Done     E: Couldn't find package vlc


I want to solve the integral $\int 1/(a^2+x^2)^n dx$. I guess this can be solved using the reduction formula as in the case of $\int x^2/(a^2+x^2)^n dx$. However, I am not able to do it.