Help debugging a $2 = 1$ proof and clearing further confusions

I found this proof of $2 = 1$ online and as usual tried to debug it.   Consider the following true statement:     $x^2 = x + x + x + ... + x$ ($x$ times)   If we differentiate both sides, we get:  $$2x = 1 + 1 + 1 + ... + 1 = x$$  Or  $$2 = 1$$  Now, the mistake was that $x^2 = x + x + x + ... + x$ was not true $\forall x \in \mathbb{R}$ and therefore we cannot differentiate both sides and except them to be equal.  However, I learnt of discrete calculus and tried to take the discrete derivative of both sides and got:  $$2x + 1 = x$$ which is also not true for all $x \in \mathbb{N}$.  So, my questions are: Why doesn't the discrete derivative give correct results?  EDIT: I have already mentioned that the statement is not true for all reals and only for natural numbers. I think this makes some of the comments here redundant.


Notify application icon using javascript

Is there any way to make the application icon, in taskbar(windows) or dock(os x) to highlight, using javascript ?  When I say highlight, is like the jumping icon in os x.  What I need is when my web app receive a websocket message, the user knows that,  even if he/she is using another application.


trigger VINfromAccountandContact on Case (before insert) {     Set<id> setConids = new Set<id>();     Map<id,id> mapAccidVsVIN = new Map<id,id>();     for(Case c:trigger.new){         if(c.Contactid <> NULL){             setConids.add(c.Contactid);          }     }     if(!setConids.isEmpty()){         for(Contact_Vehicle_Ownership__c cv :[SELECT id,Account_Name__c,Contact_Name__c,VIN_Lookup__r.id FROM Contact_Vehicle_Ownership__c WHERE Contact_Name__c IN:setConids]){             mapAccidVsVIN.put(cv.Contact_Name__c, cv.VIN_Lookup__r.id);         }     }      for(Case c:trigger.new){         if(mapAccidVsVIN.containsKey(c.Contactid)){             c.VIN__c = mapaccidVsVIN.get(c.Contactid);         }     } }   can i know how can i add this condition When accound id is not equal to null


I would like to ask to allow CTRL + K in in comments. However, I found I would create    How can I bump it to get it resolved/accepted/declined?      Editor's Note: The procedure for getting attention for issues and requests on meta sites is different, so this is not a duplicate of other general questions that ask how to get attention for questions.


An error occured while checking for updates

An error occurred while checking for updates in my PC. Terminal and software updates are not opening.


Ubuntu 16.04 LTS boots slow and I get blocking message

Is this expected or is there anything wrong with my machine?


I am creating a map on Minecraft, and I want the players to break certain blocks like trees, but I don't want them to break other blocks like stone bricks. Is there any command that can help me?


Windows batch file starting directory when 'run as admin'

I have a batch file which is in a directory and must be run from there as well because it updates files within this directory. This works perfectly fine, except when the user runs the batch file as administrator (required on Vista). Then the starting directory is C:\Windows\System32. Is there any way to still be able to know from which directory the batch file was run? I dont want the user to enter the directory manually.


Optimal location of pagefile on a system with two SSDs, with system drive faster than secondary drive

Background   My laptop has three disk drives, two of which are SSDs. The system drive is a 512 GB Samsung SSD 850 PRO, while the other SSD is a 64 GB Plextor M5M. Needless to say, the M5M is significantly slower than the 850 PRO, especially with writes. (Overall read and write performance are about 80% and 35% of the 850 PRO, respectively.) The system runs Windows 8.1 Pro and has 24 GB of memory. Pagefile size is presently set to a minimum of 1 GB and a maximum of 8 GB. While it's exceedingly rare for the system to run low on memory, this question is still relevant because some applications rely on the pagefile to function correctly regardless of the amount of physical memory available.   The question   I'm considering placing the pagefile on the M5M. However, because Windows complains that it may not be able to save a crash dump in the event of a BSOD if there is no pagefile on the system volume, it might be a good idea to leave a small pagefile on the SSD 850 PRO. (See the proposed configuration below.) I understand that doing this would slow paging operations due to the lower I/O performance of the M5M. The upshot of this, however, is that contention with system and application I/O on the main disk is avoided. As such, I'm not sure as to the practical performance impact when heavy paging occurs. I'm not really worried about NAND endurance. The SSD 850 PRO has extremely high endurance because of the underlying 3D V-NAND technology, and the M5M isn't used that much. Should I use the pagefile configuration below? What other options should I consider that might be better?


How to break long words after n chars (long genomic sequences)

I have to include relatively small genomic sequences in a Latex document (still, they are words of around 600-900 As Ts Gs and Cs) but I cannot find a way to force line wrapping after a certain number of characters.  I saw a massive amount of similar topics on the matter, most of them citing listings and discretionaries, but all of the suggested solutions rely on either the small size of the long words to manually add "invisible breakpoints", or the fact that within the words, some special characters (dots, underscores) or patterns, can be defined as breakable areas.  Unfortunately, the sequences I work on are too long to edit manually, and there's no special pattern that can be used within a discretionary, and none of these solutions would help if I want to stick to the standard 50 bases per line.  I'm really at loss of ideas, so if you would have any lead, please share!  Here is an example of sequence that I need to include:  CTCCTTGGGCTGTTATTCCGTAAAAGTATTTGTGGAAGATACGGCTGTCATACATGATATGTTTTTTGTTTATAACAATAGTTCTTTCTTTGATTTCACCATAGGTTGCCTCAAATTGCTCTTTTGTTGCTTGTCCAGCTGTTAAGACTAAATGTTTTGACCCCTCATTTATAAGACCGATTGCGTTGAATGGTAAGACATTCTGTTGTGCTGATTGTAATTCTGAATAGCTACGGATTTTTATGAAGATATAGTTTTTTAATATTGGTATTTCATTCCAGACATACTTCTGTATAAAGGATTTATTAAACGGTGTTGTTTTGATTGCTCTATAATACTTATCTTGTTGTCCTCTTAATTTTACCCAAGGTCTTTCAAACTCTTGGGAGTTAATGATTATAAGCATATTGTAAAGCTGTCCAGCTAATCCGAAGAATACTGGAAGCCAGTGGGTAAAGCTTGTCTGTTTTGGTAAAGCTGTTTGAACGTCTGACAAGAACAAGTCCAGACCTTCATATTTGTGGATTTTTTGAAACTTCATATTTTGATATGAACCGTCTACAATATCACTATATTTTACTGGTTGCCCAGTTTTTTGATTAATGTATCCAGGTCTTTAATATCTACTACTAAAACCACCGTAACCATAGTCCACGTTAGAGATATAGAGAGGTTTCGCATAAATGTGAACCCAGATTGCTTGTTGTTGTCTTTCATAACTCATTTGAAGACCAGTTTTAATGCGTTCTTTAATTGCTTGATACGTT


Are there any natural $n$ that for $ \frac {2^{n+1}-1}{n+1}$ is natural?

I was wondering if there are any $n$ that for $ \frac {2^{n+1}-1}{n+1}$ this number is natural, so:  $$k=\frac {2^{n+1}-1}{n+1}      \qquad k,n \in \mathbb{N}                 $$  let $n+1=t$  $$ k\times t=2^{t}-1              $$  Now we have that $k\;$and $\;t$ are odd, so $n\;$ is even. I tried to rewrite it into form $k,t=2a+1$, but it didn't work. So i'm curious is there even a solution to this problem because i made it by myself


While studying the Riemann - Stieltjes integral, I read this exercise in my book:  "Let $f:[a, b]\to \mathbb{R}$ be a bounded function. Denoted $L(P, f)$ the lower Darboux sum and $|P|$ the mesh of the partition $P$. Prove that for every $\epsilon>0$, there exists $\delta>0$ such that for every partition $P$ with $|P|<\delta$, we have: $\underline{\int_{a}^{b}}f(x)dx-L(P, f)<\epsilon$."  My question is: Can we generalize this problem for Stieltjes integral, with $\underline{\int_{a}^{b}}f(x)d\alpha$ instead of $\underline{\int_{a}^{b}}f(x)dx$?  Particularly, can we have this theorem?  Let $f:[a, b]\to \mathbb{R}$ be a bounded function and $\alpha$ is a monotonic function on $[a, b]$ . Denoted $L(P, f, \alpha)$ the lower Darboux sum and $|P|$ the mesh of the partition $P$. Prove that for every $\epsilon>0$, there exists $\delta>0$ such that $\underline{\int_{a}^{b}}f(x)d\alpha-L(P, f, \alpha)<\epsilon$ for every partition $P$ with $|P|<\delta$?  I don't know how the mesh of the partition relate to the function $\alpha$.


Why multiple PTR records in DNS is not recommended?

I   that using multiple PTR records in a DNS configuration is not recommended.   However, the reasons are often vague, or not so obvious, naming:    "it can cause problems",  "can trigger bugs in programs expecting a single answer" : it's the software's problem then, isn't it?! "can make DNS answer packet too large" : isn't this fixed with ?   Are these good reasons? Do you know of any other (good) reasons? All this kinda looks like a "legacy fear"...


I found this , but I am not sure if this is the same issue.  On , I did some reformatting of the indentation in the code block to make it a bit more readable and it was  for peer review. A few minutes later, it appears the OP made an edit that added some additional code. It looks like my suggested edit was applied when the OP saved his/her edit, and it looks like he got the "credit" for the edit.  I'm not really concerned about the 2 rep points; I'm more curious why this happened and if this is a bug (or limitation) in the editing feature, or if this is known/intended behavior?  Note that this is not a suggested edit that's overridden by a concurrent edit: the recorded edit starts from the post-suggested edit state (and in fact can be identical to it, as in  ).


Does untapping a creature save it from a spell that destroys a tapped creature?

My opponent cast , which says "Destroy target tapped creature". In response, I cast , which says "Untap target creature. It gets +2/+2 and gains reach until end of turn. (It can block creatures with flying.)"  Does my creature gets destroyed? I think not because of the stack, being my spell was the last to be cast.


“Awaiting EE Decision” in Manuscript Central – what does it mean?

I submitted my paper to a journal twelve days ago. In Manuscript Central, there were some changes of the paper’s status during the first two days, and as far as I can remember, these were Awaiting ADM Processing and Awaiting technical editor selection. At the third day, I saw Awaiting EE Decision which is still there.  From some previous posts I assume that such decision status is normally shown for a paper that is already reviewed by peers. Given that, it’s been only twelve days since my submission and the paper has not been sent out for peer-review yet, what could be the possible implications of the status? Just a bit curious and worried as well.


I'm currently on a system that runs only 12.04. I have downloaded the 14.04 iso file. My CD ROM isnt working so i dont have the option of installing through the CD which i followed last time when i installed 12.04.  I tried copying the iso file to a 8GB USB stick and booting from that. But due to some reason the system is not able to boot from the disk.  Even though i have been using Ubuntu for a long time, i don't get along with the terminal very well. I tried reading a couple of simple instructions on updating software through ttyl, but i'm getting some error.  Can someone help me out here.  Thanks!


\begin{subfigure} & \captionof: Main figure counter incremented twice per figure

Problem statement  I like to use the \begin{subfigure} environment from \usepackage{subcaption} in combination with the \captionof command.  This works in principle, but it seems that the particular combination of macros, environments, and packages results in the main figure counter being incremented twice per figure (rather than just once).  I am looking for a solution that retains the current combination of macros, environments, and packages. In particular, I rely on the use of \captionof for printing captions in the page margins (which is not demonstrated in this MWE).  Therefore, hacks that retain the given combination of \begin{subfigure} and \captionof{} are preferred over more elegant solutions that require different macros, environments, and packages. (However, I certainly would also be interested in pointers towards such more elegant solutions.)  Minimal (non-)working example (MWE)  Compile with single run of pdflatex:  \documentclass{article}  \usepackage{subcaption}  \begin{document}  \begin{figure}   \begin{subfigure}{0.3\linewidth}     Figure 1A     \caption{Subfig caption 1A}   \end{subfigure}   \hfill   \begin{subfigure}{0.3\linewidth}     Figure 1B     \caption{Subfig caption 1B}   \end{subfigure}   \hfill   \begin{subfigure}{0.3\linewidth}     Figure 1C     \caption{Subfig caption 1C}   \end{subfigure}   \captionof{figure}{Should be figure 1} \end{figure}  \begin{figure}   \begin{subfigure}{0.48\linewidth}     Figure 2A     \caption{Subfig caption 2A}   \end{subfigure}   \hfill   \begin{subfigure}{0.48\linewidth}     Figure 2B     \caption{Subfig caption 2B}   \end{subfigure}   \captionof{figure}{Should be figure 2} \end{figure}   \end{document}   Output


Find all polynomials $P$ such that $P(x^2+1)=P(x)^2+1$

Find all polynomials $P$ such that   $$P(x^2+1)=P(x)^2+1$$


how to flush dns of  Ubuntu 12.04 LTS (GNU/Linux 3.2.0-23-generic x86_64)  have tried many things form  and  also but nothing is working


How can I prevent Windows 10 from updating AMD video card drivers? I ask, because it installs the old drivers from 15.07, and with them my laptop starts to shut down one minute after I turn it on. Thanks in advance.


I have a squid server installed with 30 additional proxy addresses. Whenever I try to use one of these proxy addresses with a browser, like chrome, my IP shows as the main server IP as opposed to the additional address. For example, say the home IP is 192.0.0.10 and the additional IP I'm trying to use is 192.0.0.13, when going to a "what is my IP" type of site, it shows 192.0.0.10 no matter what additional address I use. Any idea as to why this might happen? Thanks for any help.


Can't boot Ubuntu 16.04 LTS after installing it alongside Windows

I'm new to the Ubuntu OS and I want to be able to run it in ANY way I can.  I made a bootable USB (not persistent) to install Ubuntu. Followed the instructions in the install, had made a partition of 35 GB before, installed it with everything going smoothly. Restarted the computer and wasn't able to boot it. I looked it up and found that I had to turn off Secure Boot (did it) and use the Boot Repair tool, used it and nothing happened.  Also tried doing a live USB with persistence to at least be able to run Ubuntu in a 16 (or 32 GB) but is not kept persistent.  Does anyone have any suggestions or can provide help?  You can find my Boot-Repair report at the link below:      If anyone finds this and haven't found any solution, try this:  Just as MichaelBay suggested, make sure everything is set to UEFI, turn off Legacy. In BIOS options enable Secure Boot. Go to Security Tab and select Add file to Secure Boot(someting like that) then loop through the files that are shown and look for ubuntu file. Select it and save changes, restart computer and boot the Boot Options Menu(F12) and the file you jut added should be shown.


Is "empty set" an element of a set? For example:  is this FALSE?:  0 ∈ {1,2,3}


Let $T\in B(H)$ be such that $\langle Tx,x \rangle = 0$ for all $x\in H$. Prove that $T=0$.

Let $H$ be a complex Hilbert space. Let $T\in B(H)$ be such that $\langle T x,x\rangle = 0$ for all $x\in H$. Prove that $T=0$. Here $\langle\cdot,\cdot\rangle$ is the inner product, and $B(H)$ is the space of bounded linear operators. How do I show $T$ that is the $0$ operator? I thought of considering $x=au+bv$ in $H$ and then $$T(x)=T(au+bv)=aT(u)+bT(v)$$ Hints would be great.


I set up the GRUB password protection on my Ubuntu LTS 14 64bits. To do that I generated a hash of the password with grub-mkpasswd-pbkdf2. Then I edited /etc/grub.d/40_custom to add those 2 lines:  set superusers="admin" password_pbkdf2 admin grub.pbkdf2.sha512.10000.EC81D.............   After updating the Grub and rebooting, the password is present BUT everywhere. If I want to boot on Ubuntu, I have to enter my password. I'd like to set up the password only for 'e' editing GRUB menu. (to avoid single user mode)  Any Ideas ?  Thanks


I ran across a flagged answer () which is basically a link to a blog post. The link explains precisely how to do what's asked in the question, so I marked the flag "invalid". Moderator disagreed, and deleted the answer.  I understand that link-only answers are frowned upon on Stack Overflow sites, and for very good reasons. However, I did not think that they are automatically considered a valid target for "not an answer" flag -- regardless of how helpful the link is. The moderator who deleted the answer obviously disagrees with me.    Why did he disagree?  Should I even bother investigating the helpfulness of the link while reviewing these kinds of flags in the future?


There is this answer   to .   from:    This above post has not been edited so I assume the first part of the answer I'm quoting from means, the post received an invalid flag.  I am not sure what @Shog is meaning.     A disputed flag is a flag that was issued on a post that then received an "invalid flag" flag from a 10K+ user. Both the original flag and the flag used to mark it as invalid will be listed as "disputed" in the respective user's flagging summary. Once a flag has been disputed, its state will not be changed by any additional action on the post.    A disputed flag is a flag that was issued on a post that then received an "invalid flag" flag from a 10K+ user. Is the invalid flag one that is issued on the flag or the post?     Why would Both the original flag and the flag used to mark it as invalid will be listed as "disputed" in the respective user's flagging summary.    What is an invalid flag, for those of us without the privilege?


What is the caching architecture of Stack Exchange?

Having a good understanding of how expensive DB queries are and the importance of caching static data, I can't understand how the question pages on these sites run so quickly.   We have a question with many answers. This is fairly simple for users who are no logged in. When a user is logged in, the site needs to determine whether the user has voted in each question, answer and see if they have favourited the question. I can understand how you could efficiently query this data using joins on a small scale, but these are going to be expensive joins on massive DB tables that can't be cached due to the dynamic user specific data that needs to be returned.   I'm guessing that paying for more and more servers would become astronomically expensive over time. Some sort if caching mechanism must be used to ensure a fast page load while keeping DB usage at a minimum.


Recently a question of mine got an unusual surge in upvotes, I guess I may have been linked from some high visibility blog or something like that.  Is there any way to know the traffic sources for a question?


Can Galois/counter mode be used for stream ciphers (Galois/stream mode)?

The authenticated encryption mode of operation  has recently gained acceptance because of its high performance due to its inherent parallelism and no pipeline stalls. It requires a block cipher having 128 bit block length which is used in counter mode, and authentication is done by using multiplication in the Galois field GF(2128).  However, some ciphers are stream ciphers instead of block ciphers. Could the block cipher used in counter mode be replaced with a stream cipher in the Galois/counter mode? Of course, it could not be called Galois/counter mode then due to not employing a counter. I think it could perhaps be called Galois/stream mode.  My initial intuition based on the  at Wikipedia is that since the block cipher in this mode of operation is only used to encrypt an incrementing counter, a stream cipher could be used, with its output stream packetized to 128-bit packets. However, I am not a cryptography expert, so such a replacement could result in some unknown form of weakness.  One difficulty would be how to obtain the hash key (a block of zero bits encrypted by the key). Perhaps the first 128 bits of the stream cipher output could be used as the hash key?


Difference ways of calling methods within the same class in C#

I want to know the difference between calling a method within the same class using 'this.MethodName' and just the 'MethodName' in C#. First Option public class Transaction     {         public bool PerformTransaction(Model model)         {             //Calling the method name using 'this'             var refNumber = this.GetTransactionReferenceNumber(model);             //Method Implementation         }                  private string GetTransactionReferenceNumber(Model model)         {             //Method Implementation         }     }  Second Option public class Transaction     {         public bool PerformTransaction(Model model)         {              //Calling the method using it's name(without using 'this' keyword)             var refNumber = GetTransactionReferenceNumber(model);             //Method Implementation         }                  private string GetTransactionReferenceNumber(Model model)         {             //Method Implementation         }     }  Which option should I use to call methods within the same class?. What is the difference between both options? and what is the best practice?


Or does it exist mathematically?  Is it really inconsistent with a common-sense, mathematics or known physical laws?   As far as I understand, if it exists, it must be far away from the "positive" matter because of repelling force, so it explains why there is no observations of such matter.   It would be also very consistent with the idea that the total energy of the Universe is zero. Doesn't it imply that the total mass of  the Universe is zero?   Can you please clarify the statements below that seem to contradict each other?  1)  -Max Tegmark.  2) Despite being completely inconsistent with a common-sense approach and the expected behavior of "normal" matter, negative mass is completely mathematically consistent and   3) Such matter would  and show some strange properties, stemming from the ambiguity as to whether attraction should refer to force or the oppositely oriented acceleration for negative mass.


Why is the integral of the derivative of f over f equal to zero over closed curves?

I'm trying to show that if $f(z)$ is analytic an $|f(z) - 1| < 1$, then $\int_\gamma \frac{f'(z)}{f(z)}dz = 0$ over all closed curves $\gamma$. Presumably, I need to show that this is an exact differential. I can rewrite $\frac{f'(z)}{f(z)}dz$ as $$\frac{f'(z)}{f(z)}dz = \left(\frac{1}{u + iv} \frac{\partial u}{\partial x} + \frac{v + iu}{u^2+v^2}\frac{\partial v}{\partial x}\right)(dx + idy);$$ however, now I need to find some $F(z)$ such that the partial derivatives of $F$ form the expression above (multiplied by $i$ for the partial on $y$). My idea was to show that both the real and imaginary parts of the differential are exact to simplify it a bit, but my algebraic manipulations don't seem to go anywhere. Is there something I'm missing; perhaps the $|f(z) - 1|<1$ condition? (For now, I'm assuming that that's just there so the denominator is not zero).


Im trying to update user image with php but im facing errors that $_FILES is not defined. Already is set but facing the same issue. I have tried to find in other answers here but its not working. File path is added on database without extension (example: photos/5f583778a818e.) but file is not moved to directory (folder). I appreciate your help!  Image Directory: dms>views>photos  public function updateuser(){       GLOBAL $conn;         if(@$_POST['first'] && (@$_POST['last']) && (@$_POST['filepath']) && !empty($_POST['filepath'])){         //if(@$_POST['first'] && (@$_POST['last']) && (@$_POST['filepath']){         //}               if($_SESSION['id']){                 $id = $_SESSION['id'];             }             $user = new UserModel();             //echo $id;             $user->first = trim($_POST['first']);             $user->last = trim($_POST['last']);             @$filetemp = isset($_FILES['filepath']['tmp_name']);             @$filename = uniqid(isset($_FILES['filepath']['name']));             @$filetype = end(explode('.', ($_FILES['filepath']['name'])));             $filename = $filename . '.' . $filetype;             $user->filepath = "photos/" . $filename;             move_uploaded_file($filetemp, $user->filepath);             //var_dump($_FILES);             //var_dump(is_dir('photos/')); check if folder is DIR                         $query = $conn->prepare("UPDATE users SET first = ?, last = ?, filepath = ?  WHERE id = '$id'");             $query->bindValue(1, $user->first);             $query->bindValue(2, $user->last);             $query->bindValue(3, $user->filepath);             $query->execute();              //print_r($_FILES);             echo "Updated";           }else{               echo "None";           }          }  Below is my html  <form method="POST" enctype="multipart/form-data">
<img id="previewImg"             src="views/<?php echo $user->filepath; ?>" alt="user-img"               class="rounded-circle mCS_img_loaded">             <input id="filepath" name="filepath" type="file" onchange="previewFile(this);" />
         <input type="submit" id="update" value="Update"  class="btn btn-primary waves-effect waves-          light">

     </form>  And my AJAX  $(document).ready(function () {       $('#update').click(function (e) {         e.preventDefault(); $.get('/myurl/')                  var first = $('#first').val()         var last = $('#last').val()      // var password = $('#password').val()       var filepath = $('#filepath').val()                  $.ajax({           url: 'profile/updateuser',           method: 'POST',           data: {             first: first,               last: last,                 filepath: filepath           },           success: function (data, textStatus) {             $('.result').html(data).show().delay(6000).fadeOut(300)           }         })       })     })


Why is my TeX font low-contrast? Can I change it?

This is how text looks like in TeX:   Here's under magnification:  This persists and looks about the same even when I print it out.  By comparison, here's how the text looks in Word (Calibri):  And magnified:  When reading the TeX paragraph, I feel like the letters are swimming before my eyes and can't be focused on. Is this font style on purpose, perhaps because it's easier to read in the long run, or is that an error in my configuration?  This happens even with the example here:


A limit with limit zero everywhere must be zero somewhere

I wish to know if the following is true:     Let $f : [\alpha, \beta]\to \mathbb R$ be a function so that    $$ \lim_{x\to x_0} f(x) = 0$$   for all $x_0 \in [\alpha, \beta]$. Then $f(x) = 0$ for some $x\in [\alpha, \beta]$.   The Thomae's function $f: [0,1]\to \mathbb R$   $$f(x) =\begin{cases} 1/q & \text{if }x= p/q\in \mathbb Q, \\ 0 & \text{otherwise.}\end{cases}$$  leads me to the above question. The Thomae function has limit zero everywhere, althought it is nonzero in $\mathbb Q$. I think I can take any countable dense subset $D\subset [\alpha, \beta]$ and construct a function which is nonzero in $D$ but limit equals zero everywhere. But I can't think of a function that is nonzero everywhere but has zero limit everywhere.


Tweak showlabels/showkeys - wrap the label

Can showlabels wrap the label in the margin? A very similar question is , but the solution of @DavidCarlisle does not solve the more general case. Consider the following MWE:  \documentclass{article} \begin{document} \begin{figure}[ht]   \centering   \rule{1cm}{1cm}   \caption{default}   \label{fig:a very very very long and detailed label} \end{figure} \end{document}   When adding the package showkeys the output is:    Similar problem occurs with the showlabels package (whether the hack of @DavidCarlisle is used or not):   So, is there a way to fix it?


How to properly split this list of strings?

I have a list of strings such as this :   ['z+2-44', '4+55+z+88']   How can I split this strings in the list such that it would be something like  [['z','+','2','-','44'],['4','+','55','+','z','+','88']]   I have tried using the split method already however that splits the 44 into 4 and 4, and am not sure what else to try.


I have seen words which are spelled either with a "z" or with a "s"  like "optimizer" and " optimiser".  I thought that the ones with "z" are wrong but on searching the web I found that both are correct. Why so? Is there any difference in the use also?


I'm using this snippet to show a spinner once a link is clicked. Some times the link .ln-edit-task is loaded via Ajax, and the snippet breaks. How do I make it work on Ajax loaded content?  jQuery(document).on("ready page:change", function() {   return $(".ln-destroy-task").on("confirm:complete", function(e, response) {     if (response) {       return showSpinner($(this));     }   }); }); showSpinner = function(el) {   return el.find(".fa").removeClass().addClass("fa fa-spinner fa-spin"); };   Note that page:change is required by Turbolinks in Rails.


For a non empty set $S$ of a group $G$,define $$S^k=\{\Pi_{i=1} ^{n} s_i |  s_i \in S\}$$ for any positive integer $k$. Prove that, if $G$ has $n$ elements, then $S^n$ is a subgroup of $G$.   I am a beginner in abstract algebra so couldn’t achieve something that I could discuss


How to update Galaxy S4 GT-I9505 from Lollipop to Nougat Android 7.0 version?

How to update the Galaxy S4 GT-I9505 from Android 5.0 Lollipop to Android 7.0 Nougat (without Root)? Currently not getting or not showing any updates either with Software Update or from Samsung Smart Switch/Samsung Kies in Galaxy S4 device.  Additionally, I do not see Android 7.0 Nougat version updates in SamMobile website with respective to the firmware.


In the course slides for the Stanford Convex Optimization course by Boyd it states that if   $$K=\{(x, t) \,|\, ||x||_1 \le t\}$$  then its dual cone is  $$K^* =\{(x, t) \,|\, ||x||_\infty \le t\}$$  Why is that?   If $x = (-t, 0)$ and $y = (t, 0)$ then $x \in K$ and $y \in K^*$ but $x^ty = -t^2$, which is negative, contrary to the definition of a dual cone.


How to compute Chebyshev bounds on probabilities: one- or two-sided inequality?

Suppose the distribution of scores of a test has mean 100 and standard deviation 16. Calculate an upper bound for the probability $P\{X>148\text{ or }X<52\}$.   Here is my progress:  By the addivity axiom, $P\{X>148\text{ or }X<52\}=P\{X>148\}+P\{X<52\}$. Can I use Chebyshev's Inequality on both probabilities or do I use the one-sided Chebyshev inequality? Or do I use the corollary from the one-sided Chebyshev inequality (stated below)?  $P\{X\ge \mu+a\} \le \frac{\sigma^2}{\sigma^2+a^2}$ (1)  $P\{X\le \mu-a\} \le \frac{\sigma^2}{\sigma^2+a^2}$ (2)  Being that the problem states $\mu$, $\sigma$ and $a$, I believe I should use (1) for $P\{X>148\}$ and (2) for $P\{X<52\}$ to get an upper bound.


Do full frame sensors have a higher exposure?

I was reading a piece on the comparison of APS-C to full frame sensors. In this article, it mentioned that full frame sensors can have larger individual "photo sites", and can therefore capture more light.  Here is the quote...     It is not the number of pixels that really counts - APS-C models such   as Canon's EOS 7D and EOS 550D have almost as many photosites, thanks   to their 18-million pixel count - but the size of the photosites is   crucial to image quality.      Bigger individual light sensors capture more light - and this means   that less electronic noise is created. You notice this most as you   increase the ISO setting - with this noise creating a coloured mosaic   pattern that is particularly noticeable in shadow areas.   Is this true? If I control for variables like aperture relative to the sensor, would a full frame sensor get higher exposure?


Is Google using the password show/hide toggle icon on their login form correctly?

Shouldn’t the icon be the action that will happen after you click/press on it? ...similar to when a video or song is playing, the icon showing is “Pause” (future state), and when it is paused, the “Play” icon is shown.


I got a carbon-framed  recently but I also want to use it for commuting to and from work and I want a place to put my lock and other stuff on the bike. Is it possible to have a rack on this kinda bike.


I used to have an icon on the Windows Vista taskbar showing the battery amount remaining (laptop). It has mysteriously vanished.  How can I get it back?  I followed the Windows  (see How can I hide the battery icon in the notification area? - hoping to reverse the instructions) but the Power checkbox on the Notification Area tab was greyed out and could not be checked or unchecked (it is currently unchecked).


Vacuum is said to have an intrinsic impedance. What is the source of this? Impedance is quite understandable in bulk matter, but I'm unable to comprehend it's presence in vacuum.


On Careers I thought it wold be nice to be able to filter by , possibly multiple, in additional to location.  Nothing fancy, but something like ....        The image of tags is stolen from the SO side to convey the idea. I suspect functionality on the Careers side would need to be a bit different.  Recent tags would likely make sense.  Favorite tags, particularly the more specific ones might not (e.g., a job posting for , ).  Anyway, the image is just to give a sense of the idea.


Price alert for a specific flight or set of flights

Is there any search engine or price alert engine that let you specify a specific flight or set of flights and receive alerts when the price goes up or down?  All sites I know let you do this but it is a generic from A to B but sometimes this A to B (on long haul) the cheapest flight is such a bad combination (like 40h long journey) that you don't really care about it, the worst is that these flights are usually the cheapest ones and they just pollute the search results and fare alert as you'll mostly be receiving alerts when those flighs go up or down and not when the flight you really want to take goes up or down.  Something like: Alert for AF7625 + AF276 + AF279 + AF7630  EDIT: Seriously, how can someone mark this question as duplicated when I'm clearly asking for a price alert engine for specific flight numbers within a route from A to B and NOT a general price alert for A to B where we will get 40h long flights that only a suicide guy would take. Where the real 15h long flights are the real flights to take in consideration for the alert engine and therefore we need to somehow just specify them and filter out those cheap 40h long journeys that no one will ever take.  I even gave an example on the original question and replied to the comments stating this is not a duplicate question and explaining why.


How to make partition in windows 8 hard disk?

I have a 1TB hard disk with windows 8.1 running on it. I want to create a partition(preferably of the size around 20 GB) from my C drive to install a linux Operating System along with windows(Dual boot). It says it has 56.2 GB in the computer window.     But when I go to the hard disk partition wizard, I am only able to shrink 801MB max. I already went through the defragmentation process with no help. If this question is a duplicate then please redirect it.


share point server name change - all the sites are down

we have installed sharepoint server 2013 on 2008 server machine and configured few sites. and after couple of days the server name has changed. (Eg: servername1 to servername2).  So when i go to database, the instance name changed to servername2 and IIS as well.  But when i run the sharepoint site url with latest servername it saying error in database. please configure from sharepoint products. then i tried to launch configure the existing server farm with latest sql server instance and database as server_config db but it saying not able to proceed.  could you please help me on this because we do not want to loose the sites which we configured previously.  Thanks in advance!


Is it possible to close questions because they are already solved?

Some questions happen to be solved for some reason (for instance, a new software version), and there's no answer it should be marked as accepted, but the question is not 'Open' anymore. And I don't think the question should be deleted because other users may have the same problem.   What's the best way to deal with this situation?  At least for me, it doesn't show up any option/action that would fit this situation on this question for instance:


Do negative modifiers change a critical hit?

I want to play a champion fighter and am considering whether or not to get the Great Weapon Master Feat which states:  Before you make a melee attack with a heavy weapon that you are proficient with, you can choose to take a - 5 penalty to the attack roll. If the attack hits, you add +10 to the attack’s damage.  If I take the -5 to attack roll and roll a critical hit, will that crit still be in effect, or will the -5 counteract that? Also, in the event that I do crit with a -5, would I add the +10 damage before, or after I double damage, like with other modifiers. It doesn't say that the +10 is a modifier specifically, so I was a bit confused (note: for critical hits, my group usually has house-rule to double the damage and then add modifiers instead of the normal double dice.)


My phone is sending messages to international number

My phone is automatically sending sms to number 6592324290 and i have been charged heavily by my service provider. I don't remember that i have installed any app which can send such sms. please advice so that at lest further sms can be stopped.


I have a list which i have initialised. i get a null pointer exception when i try to add to it. does anyone know why. here is a snippet of the problem-causing code.  Employee e=employeeskills.get(0).getEmployee();      List<EmployeeSkills> es;     es=e.getEmployeeskills();     for(int i=0; i<employeeskills.size();i++)     {            es.add(employeeskills.get(i));     }     session.getCurrentSession().saveOrUpdate(e);   employeeskills is an list of objects(EmployeeSkills). EmployeeSkills is the a type of Object.


how to put 3 different tikz pictures into a page width

My page is arranged as a two column. I have 3 different tikzpicture in one figure. I want to put these 3 tikzpictures that fit in page width not column width. Can you please help me to do this?  \begin{figure}     \begin{subfigure}[b]{0.32\linewidth}     \resizebox{\linewidth}{!}{         \begin{tikzpicture}[scale=0.40]           \begin{axis}[             title={rate},             ymin=1, ymax=5,             xmin=1, xmax=5,             xtick = {1,2,3,4,5},             xticklabels = {1,2,3,4,5},         ]%original         \addplot[black,line width=0.5mm]             plot coordinates {                 (1, 3)                  (2, 5)                  (3, 4)                  (4, 2)                  (5, 1)             };         \end{axis}         \end{tikzpicture}}         \caption{caption1} \label{fig:M1}     \end{subfigure}     \begin{subfigure}[b]{0.32\linewidth}     \resizebox{\linewidth}{!}{         \begin{tikzpicture}[scale=0.40]         \begin{axis}[             title={rate2},             ymin=1, ymax=5,             xmin=1, xmax=5,             xtick = {1,2,3,4,5},             xticklabels = {1,2,3,4,5},         ]%majority          \addplot[black, mark=diamond*]             plot coordinates {                 (1, 3)                  (2, 1)                  (3, 4)                  (4, 2)                  (5, 5)             };         \end{axis}       \end{tikzpicture}}       \caption{caption2} \label{fig:M2}     \end{subfigure}     \begin{subfigure}[b]{0.32\linewidth}     \resizebox{\linewidth}{!}{     \begin{tikzpicture}[scale=0.40]       \begin{axis}[     title={rate},     ymin=1, ymax=5,     xmin=1, xmax=5,     xtick = {1,2,3,4,5},     xticklabels = {1,2,3,4,5},     ]%original     \addplot[black,line width=0.5mm]     plot coordinates {         (1, 1)          (2, 5)          (3, 3)          (4, 2)          (5, 4)     };     \end{axis}     \end{tikzpicture}}     \caption{caption3} \label{fig:M3}     \end{subfigure} \caption{Accuracy} \end{figure}[![accuracy][1]][1]


Let $ a, m $ and $ n $ be integers such that $ m> n \geq 0 $.  i) Show that $a ^ {2n} +1$ divides $ a ^ {2^m} -1$.  ii) Show that $ (a ^ {2^m} + 1, a ^ {2^n} + 1) = $ 1, if a even; 2, if a odd (Use elementary techniques)  Attemp: $i) $ Let $m=n+k $ where $k\ge 1$. See that the problem is show that $a^{2^m}=(a^{2^n})^{2^k}\equiv 1\mod ((a^2)^n+1) $. I think you can work this by induction and show that $a^{2^n}\equiv \pm 1\mod ((a^2)^n+1) $, but I only can show it for $a=2$.  $ii) $ Suppose that $p $ is a prime that divides $a^{2^m}+1$ and $a^{2^n}+1$ then $p\mid a^{2^m}-a^{2^n}=a^{2^n}(a^{2^k}-1)\implies p\mid a^{2^k}-1 $ this yields $a^{2^k}\equiv 1\mod p $ wich since $p\mid a^{2^m} +1$ we obtain: $(a^{2^k})^{2^n}+1\equiv 2\equiv 0\mod p $  Then $p\mid 2$ and $\gcd (a^{2^m}+1,a^{2^n}+1)=\boxed {1,2} $


Considering the fact that electrons tend to take the maximum conductance path to flow from A to B. This is justified by saying that $\vec{E}$ is larger in conductors. But once similarly it was thought for gravitation, that if in a region the gravity was stronger, the mass more likely took that path, then later it was found it is actually a geodesic in space time as gravity curves space time. So is there some underlying geodesic for motion caused by electromagnetic force?


Need help on trigger which is used to update parent record when child record value changes

Hi i have written trigger in which SC_Problem_Management__c is parent object and SC_Problem_Case_Link__c is child object having master detail relationship. I want to update status field of parent object to awaiting deployment when all child records status having value as 'Tested'.  trigger updatestatus on SC_Problem_Case_Link__c(after update) {     List<SC_Problem_Management__c> parentObjList = new List<SC_Problem_Management__c>();     List<SC_Problem_Management__c> parentObjListToBeUpdated = new List<SC_Problem_Management__c>();     public List<Id> listIds = new List<Id>();     for (SC_Problem_Case_Link__c childObj : Trigger.new) {         listIds.add(childObj.SC_Problem_Management__c);     }     parentObjList = [SELECT Id,Status__c, (SELECT ID, Status__c FROM SC_Problem_Case_Link__r) FROM SC_Problem_Management__c WHERE ID IN :listIds];     Boolean checkApproval = TRUE;     for (SC_Problem_Management__c bid : parentObjList) {         for (SC_Problem_Case_Link__c bsaa : bid.SC_Problem_Case_Link__r) {             if (bsaa.Status__c == 'Tested') {                 checkApproval = TRUE;             } else {                 checkApproval = FALSE;             }         }         if (checkApproval == TRUE) {             bid.Status__c = 'Awaiting Deployment';         }         parentObjListToBeUpdated.add(bid);     }     if (parentObjListToBeUpdated.size() > 0) {         update parentObjListToBeUpdated;     } }   I am getting error while saving the trigger. "Error    Error: Compile Error: Status__c,(SELECT ID, Status__c FROM SC_Problem_Case_Link__r) FROM SC_Problem_Management__c ^ ERROR at Row:1:Column:48 Didn't understand relationship 'SC_Problem_Case_Link__r' in FROM part of query call. If you are attempting to use a custom relationship, be sure to append the '__r' after the custom relationship name. Please reference your WSDL or the describe call for the appropriate names. at line 9 column 21"  Please guide on this issue.


Allow to add incriminating evidence to a spam flag

Since a post is only considered spam if the user is associated with the product promoted, mods need evidence of the association, and .  As such, the flagging user needs to provide that evidence with the flag -- otherwise, they're forced to use a custom flag as suggested in the linked question, which defeats the purpose of a dedicated spam flag.    The justification for rejecting the previous such request, , turned out  so it may no longer apply. (That post has been updated since, with new reasoning. I updated this post with the new figures, and also gave an update at the bottom.)  It's questionable in the first place: there's no statistics on how many flags were mishandled (, rather high to really say anything) or how much time the mods wasted looking for evidence -- so there's no way to estimate the magnitude of the problem with just the data. Maybe the SO mods themselves can provide feedback here.  The previous suggestion to use comments to show evidence sort of works --    if both users and mods know to look there for evidence   which is totally not obvious due to inconsistency: the only comments to a mod flag currently possible come with the flag and are private, unlike post comments   which is reasonable 'cuz a mod flag comment exposes others' wrongdoings and thus can get people into trouble; and   if it doesn't get lost/buried among other comments   quite possible is self-promotion wasn't detected early    So, it does provide a way, but that way is far from being intuitive, convenient or, if privacy is a concern, even acceptable.    , @JonEricson now argues that obvious and non-obvious spam are significantly different things and should be handled differently.   If that's the case, the note near the spam flag entry needs to say something along the lines of: "if the fact the post is spam is not obvious, use a custom flag instead and provide incriminating evidence":   so that the users know that they should be using this workflow -- this is completely non-obvious this workflow will give hard numbers to find out if such cases really are frequent enough to warrant a more streamlined mechanism


Difference between density and probability

What is the difference between the density and probability?  I have tried R in which I can use both pnorm and dnorm for the normal distribution and pbinom and dbinom for the binomial distribution, etc.  I have tried reading the documentation but I don't think it's quite clear what the difference is between those two functions. I know that pnorm(x) gives me $P(X \leq x)$.  My guess is that the density is the value of $f(x)$ while the probability is $\int_\infty^x f(x) \, \mathrm{d}x$. If this is correct, I don't understand what the value of $f(x)$ gives me of information since only the area under the function gives me the probability.  I know that the interesting values are pdf=probability density function and cdf=cumulative density function. So maybe the pdf is the value from dnorm and is the area at a specific x while cdf is the value from pnorm and is the area from $\infty$ to the specific x. But I have learned that you cannot get the probability at a specific $x$ in continuous distributions so that explanation does not make sense.


Python - making list from a string with substrings in " "

I have a string like this:  a = '"a a a" "b b b" c d'   and I want to get a list that looks like this:  b = ['a a a', 'b b b', 'c', 'd']   Basically when there is something inside "..." I want to keep it as one element of the list.  Any ideas?


High Sierra not recognizing username when entering credentials

After a new hard drive replacement in my old iMac (late 2009) I have similar problem like the questioner who changed it to grant. My main question if I follow the direction given in the answer will it reset to old Operating system? Please help.  To be clear I will explain what happened.  I tried to change user name in preferences, clicked on the current user (advanced options), which was named 'user', which was also the administrator, and changed the name. This didn't end up changing the username. I then tried to create another administrator user.  I logged out. When I logged back in the only user available to log in with was 'user'. When I opened user preferences I see that 'user' is no longer an administrator.  I now have no way of accessing an administrator. When I try move files into the applications folder it asks for admin username and password. I've tried every combination of 'user' and 'new user name' and nothing works.


Should diamond mods have the ability to accept an answer?

I recently came across this question:    As you can tell, it was an anonymous user, so no hope of follow up. Basically they gave a self-answer along the lines of "hey thanks for your answer, that worked perfectly for me after I did a small modification". It reads extremely like a non-answer that'd be about 100 times better as a short comment.   Also, this really begs the question if diamond moderators should have the ability to mark Jon Skeet's answer as the accepted solution(the only answer other than the self-answer). It's very obvious that this is the solution, but if the non-answer is deleted rather than put into a comment, it won't be clear for some person that came from google. While if the answer was accepted, it would be..   What do you think we should do in this kind of situation?


What does the number in {} for Bibilography actually do?

In   There was an example of using Bibilography:  \begin{thebibliography}{9} \bibitem{latexcompanion}  Michel Goossens, Frank Mittelbach, and Alexander Samarin.  \textit{The \LaTeX\ Companion}.  Addison-Wesley, Reading, Massachusetts, 1993.  \bibitem{einstein}  Albert Einstein.  \textit{Zur Elektrodynamik bewegter K{\"o}rper}. (German)  [\textit{On the electrodynamics of moving bodies}].  Annalen der Physik, 322(10):891–921, 1905.  \bibitem{knuthwebsite}  Knuth: Computers and Typesetting, \\\texttt{http://www-cs-faculty.stanford.edu/\~{}uno/abcde.html} \end{thebibliography}   What does {9} do here? As explained in the article: A parameter inside braces, 9 in the example, indicates the number of entries to be added; this parameter can not be greater than 99.  However, in a previous document with over 50 citations/entries. I only needed to do {1} and not {50}. Can someone solve this contradiction to me?


Why is coefficient of determination used to assess fit of a least squares line?

The coefficient of determination is $$r^2 = 1 - \frac{SS_\text{res}}{SS_\text{tot}}$$ where $SS_\text{res}=\sum_{i=1}^n (y_i-\hat{y_i})^2$ and $SS_\text{tot}=\sum_{i=1}^n (y_i - \overline{y})^2$.  Why is this used for assessing the fit of a least squares line? Why is the comparison based on looking at $SS_\text{res}/SS_\text{tot}$ as opposed to say $SS_\text{res}/n$ or something else?


How much money do you have in savings - UK Visitor visa , Could I show mutual funds and Stock market investment as savings?

I was asked to enter "how much money do you have in savings" while I was filling my UK Visa form. I have entered the amount I current have in my Bank Account.  I have also invested in mutual funds and stock market, could I add those amounts to my bank balance and include it in my savings ?  If the answer to question above is NO then :  I can sell shares and redeem my mutual funds and I will receive the amount in my Bank account within 1-2 days ? Could I then show it as my savings ?  I am a salaried person so I can show proofs for funds added to my account by submitting salary slips, but How will I show proofs for the amount credited to my account by selling shares or redeeming mutual funds ?  Please help !


"will" and "be going to", which is correct to express this situation?

I'm wondering which one of "will" and "be going to" is more appropriate to mention the event which seems to definitely happen without fail in the future? For example:   He is going to be 10 years old next month. He will be 10 years old next month.


In a DC circuit, imagine a resistance of 10 Ohms connected parallel to a resistance of 20 Ohms, which is also parallel to a battery of V volts. In such a case, current will be distributed to the two of them. However, in a short circuit, no current would pass through the resistance. Why does this happen? If the path of electrons is obstructed by the accumulation of electrons at the resistance, shouldn't the same happen in the above case as well?


I came to the US from the UK on September 1st and spent the full 90 days travelling round under the VWP and an ESTA. After my 90 days were up I have come to Mexico, where I will be spending 6 weeks in the country.  As of yet I do not have a flight booked back to the UK but have stared to look before I return home, I would love to stop in Salt Lake City for a week to see my brother.  Does anyone know if this is possible, having spent 6 weeks out of America would I be able to return for a week on a new VWP with a flight booked back to the UK?  Having read a few things online which suggests I can and others that say I can't.


Why didn't Thor take Loki's staff with him?

At the end of The Avengers, Thor takes Loki with him to Asgard as a prisoner. He also took the Tesseract. But why didn't he take Loki's staff? Seeing that S.H.I.E.L.D. used the Tesseract to make weapons of mass destruction, he will surely realize that the staff was of great power and earth's people could use it for making weapons. So why didn't he take the staff with him?


Best way to set enviroment variables for all processes

What is the best and standard way for setting env vars in Linux so they are visible for all processes (and users) ?  Is adding them to  /etc/environment the best practice ?


apt-get update not working after vpn issue

By mistake, I tried the command sudo apt-get update while I was connected by vpn. However, I closed the vpn connection and now when I try to update the following error appears:  Hit:1 http://packages.microsoft.com/repos/vscode stable InRelease  Get:2 http://security.ubuntu.com/ubuntu focal-security InRelease [107 kB]                                        Ign:3 http://ppa.launchpad.net/webupd8team/java/ubuntu focal InRelease                                                                 Err:4 http://ppa.launchpad.net/webupd8team/java/ubuntu focal Release                                                                     404  Not Found [IP: 91.189.95.83 80]  Hit:5 http://in.archive.ubuntu.com/ubuntu focal InRelease                                                                   Hit:6 http://dl.google.com/linux/chrome/deb stable InRelease                                                                Get:7 http://in.archive.ubuntu.com/ubuntu focal-updates InRelease [107 kB]                                                  Get:8 http://in.archive.ubuntu.com/ubuntu focal-backports InRelease [98.3 kB] Get:9 http://security.ubuntu.com/ubuntu focal-security/main amd64 DEP-11 Metadata [16.6 kB] Get:10 http://in.archive.ubuntu.com/ubuntu focal-updates/main amd64 Packages [122 kB] Get:11 http://security.ubuntu.com/ubuntu focal-security/universe amd64 DEP-11 Metadata [208 B] Get:12 http://in.archive.ubuntu.com/ubuntu focal-updates/main i386 Packages [59.8 kB] Get:13 http://in.archive.ubuntu.com/ubuntu focal-updates/main Translation-en [44.6 kB] Get:14 http://in.archive.ubuntu.com/ubuntu focal-updates/main amd64 DEP-11 Metadata [90.4 kB] Get:15 http://in.archive.ubuntu.com/ubuntu focal-updates/universe i386 Packages [27.3 kB] Get:16 http://in.archive.ubuntu.com/ubuntu focal-updates/universe amd64 Packages [68.3 kB] Get:17 http://in.archive.ubuntu.com/ubuntu focal-updates/universe Translation-en [28.3 kB] Get:18 http://in.archive.ubuntu.com/ubuntu focal-updates/universe amd64 DEP-11 Metadata [136 kB] Get:19 http://in.archive.ubuntu.com/ubuntu focal-updates/universe DEP-11 48x48 Icons [66.0 kB] Get:20 http://in.archive.ubuntu.com/ubuntu focal-updates/universe DEP-11 64x64 Icons [104 kB] Get:21 http://in.archive.ubuntu.com/ubuntu focal-updates/universe DEP-11 128x128 Icons [264 kB] Get:22 http://in.archive.ubuntu.com/ubuntu focal-backports/universe amd64 DEP-11 Metadata [532 B] Reading package lists... Done        E: The repository 'http://ppa.launchpad.net/webupd8team/java/ubuntu focal Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.   Is this a vpn issue or an IP issue? I am unable to figure it out. Please suggest.


The first occurence of the first two columns

I've got this file:   aaa.bbb.ccc.ddd aaa.bbb.eee.ccc ggg.hhh.jjj.kkk fff.uuu.yyy.ddd eee.rrr.ddd.bbb eee.rrr.www.zzz eee.rrr.sss.nnn eee.rrr.qqq.kkk   I want to filter it so it displays the whole line only when the first occurrence of the first two columns happens.   The expected output is:  aaa.bbb.ccc.ddd ggg.hhh.jjj.kkk fff.uuu.yyy.ddd eee.rrr.ddd.bbb   So far what I could do was:  cat file |awk -F"." '{print $1"."$2}' |uniq -c   but it only shows the first first two columns and the number of repetitions.


We have that $$(x+y)^n=\sum_{k=0}^n\binom{n}{k}x^ky^{n-k},$$ but is there such a formula for $(x+y+z)^n$ ?


How to position a figure enviroment above footnote?

It's a simple question: I'd like to put figure on the bottom of the page, but above footnote. I'm using memoir, but with documentclass{article} the result is the same.  Example:  \documentclass[article]{memoir}  \begin{document} Some text\footnote{The footnote}  \begin{figure}[b] \vspace{2cm} \caption{Bild 2} \end{figure}  \end{document}   I don't want to use a process of trial and error for each figure in my document, "hacking" the position option with an [h].


How to change Blender's default startup settings?

How can I change Blender from the default cube/lamp/camera default setup? Also, is it possible to change other features, such as the default view direction (Top, Side, etc) or the Editor type (3D View, Node Editor, Graph Editor, etc)?


Compiler not recognizing that class string value is equal to another String value

public class Station {     String name;     boolean pass;     int distance;      // method to create a new Station taking the arguments of the name,pass and distance in the parameter     public static Station createStation(String name, boolean pass, int distance) {       }      // Array list containing all the Stations in London we will use     static Station[] StationList = {createStation("Stepney Green", false, 100), createStation("Kings Cross", true, 700), createStation(             "Oxford Circus", true, 200)};      public static String infoAboutStation(Station station) {         String message;         if (station.pass)             message = //string message         else             message = //string message         return message;     }      public static String checkInfo(String stationName){         String info = null;          for(Station station : StationList){                  if(stationName == station.name) { //it does not recognise it to be the same for some reason                 info = stationName + infoAboutStation(station);             }             else                 info = stationName + " message ";         }         return info;     }      public static void printInfo(){         Scanner scanner = new Scanner(System.in);         System.out.println("How many... ");         int totalResponses = Integer.parseInt(scanner.nextLine());          String choice;         for(int i = 0; i < totalResponses; ++i){             System.out.println("Enter a station: ");             choice = scanner.nextLine();             System.out.println(checkInfo(choice));         }     }     // psvm(String[] args) }  So the program runs fine but when we use "Stepney Green", "Kings Cross", "Oxford Circus" as the input for choice at checkinfo(choice), it does not recognise it to be the same for stationName == station.name in the method checkInfo(stationName //choice) Intellij debugger reads this at stationName == station.name -StationList = {Station[3]@980} -> 0 = {Station@994} 1 = {Station@997} 2 = {Station@998} -static -> StationList = {Station[3]@980} -stationName = "Stepney Green" value = {byte[13]@996} coder = 0 hash = 0 hashisZero = 0 -info = null -station = {Station@994}  -> name = "Stepney Green", pass = false, distance = 100 -station.name = "Stepney Green" -> value = {byte[13]@999] rest is zero Beside the statement it says stationName: "Stepney Green" station: Station@994. Instead of printing out stationName + infoAboutStation it goes to the else station and prints "Stepney Green is not a London Underground Station". I am so puzzled as to why. Also if you don't mind helping me as to making this code a little more efficient and better.


Subj. The expiration time is about 1 hour or so. This is very inconvenient:   If I leave a query open, after some time it becomes inoperative - impossible to execute and the editor glitches I have to login every time - which I don't have to at other SE sites


Simple Harmonic Motion - What are the units for $\omega_0$?

I'm trying to understand the units in:  $$mx''+kx=0$$  And the general solution is $$x(t)=A \cos(\omega_0 t)+B \sin(\omega_0 t).$$  Let $\omega_0 =\sqrt{\frac{k}{m}}$ - the unit for the spring constant $k$ is $kgms^{-2}$ or $Nm^{-1}$, where $m$ is in $kg$, so that the units of $\omega_0$ seem to be "per second" (i.e) $1/s$.  But, later we put $\omega_0$ in to the $cos$ and $sin$ functions which will return dimensionless ratios. So, The constants $A,B$ must be in $m$, since $x$ is in $m$.  What I don't understand is why my book says $\omega_0$ has the unit $rad/s$, I get that the input for cosine is $rad$ or some other angle measure, but where did the radians come from?  My analysis of units only proved $1/s$ as the actual units..!    I have just been informed that radians are dimensionless. So, that answers part of this question, yet I still don't know why we can't say that dimensionless one in degrees or rotations..? How do I know what kind of cosine and sine table to use with this dimensionless number?


Attempt to invoke virtual method" ImageView.setImageDrawable" on a null object reference

When program comes to this function it just crashes. I have no idea why this doesn't work. If you need more code - just write.   int drawableId = getResources().getIdentifier("br" + mQuestionNumber,"drawable",getPackageName());         mQuizSlikaImgView.setImageDrawable(getDrawable(drawableId));


Quick way to solve simple probability questions like these?

Two dice are rolled. What is the chance of rolling at least ONE six? (The answer is $\frac{11}{36}$.)  My solutions manual has a very elaborate table drawing method and I don't want to do that. I need something more quick. (I could have drawn the table in the time it took me to answer this question and so forth, but I'm keen on learning new methods!)


I'm looking for jobs all over the interwebs and I keep seeing postings by companies saying that applicants need to be well versed in most Adobe creative solutions softwares and then QuarkXpress.  But, when I look at actual studio ads (small studios looking for a new designer) they only mention strong Adobe skills.  Is QuarkXpress still relevant? Or is it a legacy software that only gets mentioned because at one time in the past it was one of the best softwares to use?  I know this might be a very subjective question, but I'm looking for those who ave been in the design world a lot longer than I have to give me insight (I've only just begun my design career).


What does "mathematically well defined" quantum field theory mean?

Reading Wald's book (page 380, end of the first paragraph of section 14.1) while the author is giving an overall discussion of quantum field theories you can read     However, for the more interesting case of a theory with interactions (i.e., for a field or fields satisfying nonlinear equations) one is led unavoidably to consider the products of field operators at the same spacetime point. Such quantities have no natural mathematical meaning, and consequently, with the exception of some simple models in lower spacetime dimensions, there are at the present no known examples of quantum field theories of physically reasonable interacting fields which are mathematically well defined.   What does Wald exactly mean by mathematically well defined, which are the problems, for example in QED that make it ill defined?


So I'm trying to understand bootstrapping,  I watched the following video:    And starting from 2:53 the speaker explains that through bootstrapping we can get a closer inference on the population mean by creating a sample distribution of random samples from our original sample  I tried to visualize this in python with the following code:     However, as you can see, the if I make a sampling distribution of my sample I get a distribution that's centered around the sample mean, not the population mean.   This actually makes sense to me, but because of this result I don't understand the purpose of bootstrapping. Could someone explain how bootstrapping works?  EDIT: I read the answer here:   And it still doesn't make sense to me based on the way that i've visualized it. To me, it seems that I'm only getting information about the sample, not the population.


Prove that $\det A = 1$ with $A^T M A = M$ and $M = \begin{bmatrix} 0 & I \\ -I &0 \end{bmatrix}$.

Prove that $\det A = 1$ with $A^T M A = M$ and  $M = \begin{bmatrix} 0 & I \\ -I &0 \end{bmatrix}$ ($I$ is the identity matrix of order n).


Prove that if $a|bc$ and $\gcd(a,b)|c$ , then $a|c^2$

Honestly, I'm just not sure where to start at all. I've just been staring at this for a while


Need a word for someone that makes requests of others, but doesn't do that for the other person

Like, your husband asks you to be quiet when you come in late, then is loud when he comes in late.  Or not to talk across rooms, but is constantly yelling from other rooms himself?  Sentence I would use it in:  I wish that you would follow your own rules, as I find your behavior very XXXXX and not fair.


Grouping curly brace inside curly braces with Regex

Given this string some noise //some more noise Cherry {  something 0  blah 1000  something 120  super { something else }  super { again } } Peach {  apple 1  caramel salted } Banana {  yellow 12  super { very yellow }  super { delicious } } Apple {  red 12 }  How would I capture each fruit AND within a fruit, if a 'super' line is present, group content of their curly braces . I'm not far using this : ^\S\w+\s\{([^}]+)\}  But if you look at the picture below, it is currently stopping at the first '}' instead of grouping the content between curly braces of the 'super' lines  I hope that makes sense . Thank you


At very high speeds, why don't many things become black holes due to increase in mass and reduction in volume?

When a body travels at a very high speed, as far as its concerned, everything is in motion except itself, so according to the body everything around it looses length in the direction of motion and gains mass. Keeping these two facts in mind, should it not be possible to travel so close to the speed of light, that due to increase in mass and decrease in volume that for the moving body many things around it should turn into a black hole?   What's wrong here? The only thing that I'm unsure about in this obviously false assertion is the relativity of mass and how its supposed to increase with velocity.  All answers will be appreciated, thanks a lot.


How can we show that any automorphism of $\mathbb{Q}$ under addition is of the form           $x \to qx$ ,for some q in $\mathbb{Q}$.  edited- I found the same question was asked by @tattwamasi-amrutam tagged automorphism from $\mathbb{Q}$ to $\mathbb{Q}$.there is some useful answer.


Is there something wrong with the way Stack Exchange is sorting sites by name?

There seems to be something wrong with the sorting of Stack Exchange sites by name:    elementary OS and Русский язык appear in the wrong place at the end of the list.


AWS EC2 - How can I recover files now that I'm no longer able to SSH into my server instance?

(I'm very inexperienced with servers)  After getting frustrated with some permission issues on my AWS EC2 instance I decided I would do the command:  chmod -R 777 /   I thought that would change the permissions of the folder I was in, but it seems to have affected every file on my server instance. As a result, I can no longer SSH into the server. It simply says connection failed.  The only image of the server I took was from way too long ago and doesn't have the files I want.  Is there a way I can simply download the files I want from the AWS console, and then from there just upload them to a new instance?  Edit  The reason that I can no longer login is because the key pair (as well as several other files) cannot be found with the new 777 permissions, thus preventing me from logging in.  This is however, not my question. My question is how to get these files.


Why didn't someone recast the Fidelius Charm on Grimmauld Place?

If they knew the place was compromised with Snape knowing its location and the Order thinking him a traitor, why didn't someone just remove and recast the Charm? Obviously, we know that he didn't tell the Death Eaters. The idea that how to cast the Charm isn't widely known doesn't hold weight either as someone within the Order cast the Charm on Shell Cottage. Unless they specifically had to learn it for that, but at the same time, the same logic applies, why didn't they just do that for Grimmauld Place?  For that matter, a Fanfic that I read that was released after HBP figured the idea out. Even if it was going on the original logic that if the Secret Keeper (or the caster, can't remember which.) dies, the Charm cancels out. I guess that Hermione was right, Wizards really don't use Logic a lot do they? But I'm surprised that Hermione didn't come up with the idea herself for that matter.


Just installed UBUNTU 12.04.3 - XTERM XT Error Can't display

I am new, just installed Ubuntu and trying to see the output of commands. I can't open/don't know how to open a terminal window.


I'm modifying some code of a text search box, now I have the following code    $categories = maybe_unserialize(get_option('_fm_categories',array()));     $pluginsurl = plugins_url();     $comcat = '';     $sw = 6;     if($cat_view == 'compact') {         $comcat = "
".''.__('Category:','wpdmap').''.wpdm_dropdown_categories('wpdm-cats-compact', '', 'wpdm-cats-compact', 0)."
";         $sw = 3;     }     $html = '
     <form id="srcp" style="margin-bottom: 10px">
     <input type="hidden" name="category" id="initc" value="'.$category.'" />          '.__('Search Package','wpdmap').':     <input type="text" class="form-control" name="src" placeholder="'.__('Search Package','wpdmap').'" id="src">          Buscar      '.$comcat.'           '.__('Orden por:','wpdmap').'     <select name="order_by" id="order_by" class="selectpicker">     <option value="date">'.__('Publish Date','wpdmap').'</option>     <option value="modified">'.__('Last Updated','wpdmap').'</option>     <option value="view_count">'.__('View Count','wpdmap').'</option>     <option value="download_count">'.__('Download Count','wpdmap').'</option>     <option value="package_size_b">'.__('Package Size','wpdmap').'</option>     </select>               '.__('Orden:','wpdmap').'     <select name="order" id="order" class="selectpicker">     <option value="DESC">'.__('Descending Order','wpdmap').'</option>     <option value="ASC">'.__('Ascending Order','wpdmap').'</option>     </select>

     </form>

     '.__('Inicio','wpdmap').'      '.__('All Packages','wpdmap').'

';   But when I press the enter button to search nothing happened, I solved this issue with a button with the following code  Search   And now it works perfectly when I click that button, but now I want it to work when I enter the text and just press enter.


Why were the trailers so different to the final film?

I don't really understand where from they took those parts. Usually trailers contain main scenes from the film to convince fans to go to the cinema. But Infinity War trailer contains scenes, that film didn't contain. They fight in the woods, Bruce turns into the real Hulk and Wakanda is left a long way behind. Why did they include parts that were not in the film?


What is the preferred GRE Writing score for MS/CS student?

I am planing to apply to study in graduate school, major in computer science/engineering. I just took a GRE test, this is my 1st time, and the result is pretty...not so good :(  Most schools, the science or engineering related program, reveals the average or preferred GRE scores for quantitative and verbal sections for admitted students. But it seems they don't care about the score of Analytic Writing section. Really?  To be honest, my writing score really bumped this time. I want to know if there's a preferred score range for this section.


I am getting the following error frequently while retrieving file object from database column. How can I resolve this problem?  May 8, 2009 3:18:14 PM org.apache.catalina.core.StandardHostValve status   WARNING: Exception Processing ErrorPage[errorCode=404, location=/error.jsp]   ClientAbortException:  java.net.SocketException: Connection reset by peer: socket write error   at org.apache.catalina.connector.OutputBuffer.doFlush(OutputBuffer.java:327)   at org.apache.catalina.connector.OutputBuffer.flush(OutputBuffer.java:293)   at org.apache.catalina.connector.Response.flushBuffer(Response.java:537)   at org.apache.catalina.core.StandardHostValve.status(StandardHostValve.java:286)   at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:136)   at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)   at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)   at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)   at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)   at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)   at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)           at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)   at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)   at java.lang.Thread.run(Unknown Source)  Caused by: java.net.SocketException: Connection reset by peer: socket write error   at java.net.SocketOutputStream.socketWrite0(Native Method)   at java.net.SocketOutputStream.socketWrite(Unknown Source)   at java.net.SocketOutputStream.write(Unknown Source)   at org.apache.coyote.http11.InternalOutputBuffer.realWriteBytes(InternalOutputBuffer.java:746)   at org.apache.tomcat.util.buf.ByteChunk.flushBuffer(ByteChunk.java:433)   at org.apache.coyote.http11.InternalOutputBuffer.flush(InternalOutputBuffer.java:304)   at org.apache.coyote.http11.Http11Processor.action(Http11Processor.java:991)   at org.apache.coyote.Response.action(Response.java:182)   at org.apache.catalina.connector.OutputBuffer.doFlush(OutputBuffer.java:322)   ... 13 more


How to know what program uses which bandwith.

From few days my Internet connection is being used by some application internally by my system.        I want to know which application is using it? I used Task Manager to see which resource is using my network it just say svchost.exe   (which is internally running more services, processes can't figured it   through it)   Can I restrict my Internet access to only certain applications (I think you are gonna say firewall, i even tried it but it is making   my system damn slow, i have an Intel i7 with 8GB RAM, so i uninstalled   it)   And this usage of Internet making CPU usage more than 15% which make my PC hotter. In turn makes my fan runs fast which in turn makes   sound. Immediatly after disconnecting my Internet my CPU usage will go   normal (1 or 2 % mostly even with lot of apps opened)


Can certain classes replace cantrips with other spells when they level up?

Many classes: bard, ranger, sorcerer, and warlock have this type of text in their Spellcasting or Pact Magic feature under Spells Known of 1st Level or Higher:     Additionally, when you gain a level in this class, you can choose one of the spells you know and replace it with another spell from the spell list, which also must be of a level for which you have spell slots.   Can I choose to replace cantrips or only spells of 1st level or higher?


Can an Indian citizen visit Dubai on a layover?

I am an Indian citizen and am travelling from New York to India via Emirates Airlines. There is a 7-hour layover at Dubai international Airport (DXB). I want to visit Dubai for a couple of hours. Do I need a transit visa? If so, how do I obtain one?


How to run a shell script on 10 hosts simultaneously?

Currently I am monitoring 10 hosts. I want to write a script which will calculate the disk space in every 24 hours and then if the file system of a host is critical for any host then it will move the old files from that host to the host which has the largest disk space?


Why is only ) a special character and not } or ]?

I'm reading  to touch up on my Regex.  In the second chapter, Jan has a section on "special characters:"     Special Characters      Because we want to do more than simply search for literal pieces of text, we need to reserve certain characters for special use. In the regex flavors discussed in this tutorial, there are 12 characters with special meanings: the backslash \, the caret ^, the dollar sign $, the period or dot ., the vertical bar or pipe symbol |, the question mark ?, the asterisk or star *, the plus sign +, the opening parenthesis (, the closing parenthesis ), the opening square bracket [, and the opening curly brace {, These special characters are often called “metacharacters”. Most of them are errors when used alone.      (emphasis mine)   I understand that only open square bracket and open curly brace are special since a close brace or bracket is clearly a literal if there's no preceding open. However, why does Jan specify that close parenthesis is a special character if the other two close's aren't?


I have installed a package using snap and I need to modify one of the files but when I try to change its ownership or permissions, I always get the following message:  sudo chmod +x ./my_file.js chmod: changing permissions of '/snap/my_app/my_file.js': Read-only file system   How can I modify files that are installed via snap?


Why do we not write the residuals in a logistic regression equation?

I've been looking at the equation for a logistic regression, which is normally given by $logit(p_i)= \beta_0 + \sum_{j=1}^{k} \beta_j x_{ij}$. All of the sources I've looked at don't state the residuals in the model equation. Why is this? Whenever we mention a linear regression equation, we always add $+\epsilon_{i}$ at the end.


What SD card type and brand would be the fastest and most reliable for a Pentax K-01 DSLR camera?


Is there any performance reason to declare method parameters final in Java?  As in:  public void foo(int bar) { ... }   Versus:  public void foo(final int bar) { ... }   Assuming that bar is only read and never modified in foo().


Show that ${n \choose 1} + {n \choose 3} +\cdots = {n \choose 0} + {n \choose 2}+\cdots$

Show $${n \choose 1} + {n \choose 3} +\cdots = {n \choose 0} + {n \choose 2}+\cdots$$  A hint is given to consider the expansion $(x-y)^n$  However, when I plug in a number for $n$, I don't get an equality. $n=5$, for instance, I get $5+10 = 1 +10$.  How is this equality possible?


I want know how to use \ref. I don't know why it doesn't work.  \documentclass[11pt,a4paper]{article} \usepackage[latin1]{inputenc} \usepackage{amsmath} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{graphicx} \usepackage{hyperref} \begin{document} Welcome to the \label{here}reference \newpage go to reference~\ref{here} on page 1 \end{document}   Thanks for help me.


I have the problem, that our website has the same name as our domain. Our website is hosted by an external comapny. Now all computer in our network can't access our website, because the DNS always resolve the ip to the domain controller. Is there a method, that the DNSs server do resolve all requests for port 80 to another IP-Address (In my case, the extern ip address)?  Thank you!


Will a 26x1.50 or 26x1.25 slick fit on a rim that I now have with a measure on the tire 26x2.00 and the rims I have are 26inch bontrager AT-550?


What's the difference between file and open in Python?  When should I use which one?  (Say I'm in 2.5)


Selecting data from the database doesn't work

i made a registration and login form where the user can add a profile pic. When they login they are redirected to dashboard.php. There i want to show them their name and profile pic but only for the active user.   At this moment, this is my code:     <?php session_start(); require_once 'header.php'; /*Veradneren + aanpassing navigatie.php*/ $current = 'dashboard.php'; require_once 'navigatie.php'; function getImage() {     require "connectie.php";     $user = $_SESSION["username"];     try {         $stmt = $db->prepare("SELECT * FROM gebruiker WHERE username = $user");         $stmt ->bindParam("username",$user);         $stmt->execute();         $results = $stmt->fetchAll();             return $results;     }      catch (PDOException $e) {         $message = $e;     } } ?>
     <?php echo $message;?>

<?php echo "Welkom, " . $_SESSION["username"];?>
             <?php                 $results = getImage();                 foreach ($results as $row){                     echo "                         ";                 } ?>

  <?php require_once 'footer.php'; ?>    Database structure:   The pictures are uploaded in the folder uploads


How to display citations in tex grouped as [1]-[3] in stead of [1,2,3] in beamer slide?

I am giving a presentation in the beamer class. I would like the grouped bibliographic references to be displayed as [1]-[3] instead of [1-3]. \documentclass{beamer} \usetheme{AnnArbor} \usecolortheme{beaver}  \usepackage[brazil]{babel}       \usepackage[T1]{fontenc}         \usepackage[utf8]{inputenc}      \usepackage[square, comma, sort&compress]{natbib}  %\usepackage{cite} \begin{document}  \begin{frame}     References \cite{rodrigues2016unbalanced, rodrigues2016considerations, monteiro2018unbalanced}. \end{frame}   \begin{frame}[allowframebreaks]{References}     \tiny          \bibliographystyle{mmc-unsrt}     \bibliography{my_bibliography} \end{frame}  \end{document}  I tried to include the \renewcommand\citepunct{], [} and \renewcommand\citedash{]-[} commands in the preamble but it didn't work. They worked in the article class but in the beamer they don't work.


Martingale in probability and Statistics

Let $(X_n)$ be a supermartingale such that $EX_n$ is constant. show that $X_n$ is a martingale. My problem here in this question is how can I use the constant expectation concept given to prove the statement.


Overlapped Stack Exchange sites for non-existing site

The footer for a non-existing site, e.g. , contains overlapped text:        Is this behavior intentional?


Is it possible to backup individual files with Deja Dup?

In the Deja Dup preferences, it is possible to select certain folders to backup and certain folders to exclude.  I would like to be able to backup individual files in my Home folder (Such as .vimrc and .bashrc), but I don't see any way to do this.   So my question is, is it possible to either     Select individual files (instead of whole folders) to backup, or backup my Home folder, but exclude all subfolders?


Why is a projective module called "projective"?

Is it related to projections as in $P P = P$?


What is the injective hull of $\mathbb Z_n$?  I know that in case $n=p$ is prime, the injective hull would be isomorphic to $\mathbb Z_{p^∞}$, but in general case, I have no idea. Can anyone be of some help to me? Thanks in advance!


Why does Ubuntu Software Center not show every package available?

The Software Center in Ubuntu 16.04 (Gnome Software) shows only part of the packages available. While e.g. apt list qtcreator correctly lists the corresponding package a search in Software Center finds nothing.  Is there something misconfigured? I upgraded from 15.10. Until now I have used the old Ubuntu Software Center which worked fine.


Concord of "scholarly enquiry combined with introspection"

What is correct:        Scholarly enquiry combined with introspection reveals    Scholarly enquiry combined with introspection reveal


Funny short story on man and insect that land on new planet and irritate war-loving inhabitants

I read the really funny story about 30-40 years ago, probably around the 1970's to 1980's. It was a short that tells how 3 races (one human, one insect-like and one ???) land together on a new planet with a species that is really annoyed that the strangers just sit on the ledge of the door of the spaceship instead of attacking them.  Eventually they take the human and imprison him. While he's there, the insect flies inside to work out the plan to get this planet to cooperate with them.


How would I Manually Make a 'Custom" Base64 Encoder/Decoder

I have took many HTML/CSS/JS Classes, but none have explained to me about anything I'm asking now. In the most basic terms I want to know how to make Specific Letters/Symbols Overwrite letters/Symbols in the input and output the leftover string, basically trying to make my own "Custom Base64 Encoder" but I don't exactly know where to start. I have my custom Strings to replace all the letters numbers and basic symbols, (Im using my own Custom ASCII Strings.) but like I said, whats a simple way I can make 1-5 length strings replace numbers/letters/symbols and then do the reverse to also Decode them? Its for a personal project.  Ive tried using a Manual Base64 encoder/decoder and editing the code, but most simply use atob or similar functions.  Also I haven't started with the Code, I'm truly not sure where to start.  I Haven't had any successful results at making a simple custom encoder/decoder.  EDIT: This is the Encoder File (View as .txt file or it may look wierd): Place it in URL Bar  data:text/plain;base64,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


Remove or prevent sidebar from opening by default on Adobe Reader

In Adobe Acrobat Reader DC, presently 2015.007.20033, how do I prevent the sidebar from opening by default?  It's not so bad when a PDF document is in portrait mode, but opening one in landscape takes up too much real estate.      February 1, 2017 update  The  is no longer correct for newer versions of Adobe.  Please refer to  for newer versions of Adobe; both Windows and Mac.


Install 4.0 Linux Kernel od Ubuntu 14.04 i686

I like to install linux 4.0 kernel on ubuntu 14.04 but i don't find any file for i686.


Display solution/file path in the Visual Studio IDE

I frequently work with multiple instances of Visual Studio, often working on different branches of the same solution.   used to display the full path of the current source file in its title bar, but Visual Studio 2005 doesn't appear to do this. This makes it slightly more awkward than it should be to work out which branch of the solution I'm currently looking at (the quickest way I know of is to hover over a tab so you get the source file's path as a tooltip).  Is there a way to get the full solution or file path into the title bar, or at least somewhere that's always visible, so I can quickly tell which branch is loaded into each instance?


Is there any method to close connection similar to  for  in WordPress?  Is it not necessary to close connection for global $wpdb?


Error accessing PostgreSQL using Eclipse Windows 10

I am in the process of learning Java and PostgreSQL. I am running Windows 10 with JRE 10, my IDE being Eclipse Oxygen 3a. I had written the following code:  import java.sql.Connection; import java.sql.DriverManager;  public class PostgreSQLJDBC {    public static void main(String args[]) {       Connection c = null;       try {          Class.forName("org.postgresql.Driver");          c = DriverManager             .getConnection("jdbc:postgresql://localhost:5432/testdb",             "postgres", "123");       } catch (Exception e) {          e.printStackTrace();          System.err.println(e.getClass().getName()+": "+e.getMessage());          System.exit(0);       }       System.out.println("Opened database successfully");    } }   It successfully compiles. However, it gives me the following error     java.lang.ClassNotFoundException: org.postgresql.Driver   In following the advice given in Stack Overflow, I have downloaded postgresql-42.2.2.jar and placed within C:\Program Files\Java\jre-10.0.1  I then edited my system variables and added "C:\Program Files\Java\jre-10.0.1" into it. However I still get the same error. Please help


I know This is not related to development, please accept me this time. I'm looking to upgrade windows 8.1 to windows 10 .   Can I able to install SharePoint 2013 on windows 10?  I couldn't find any articles about SharePoint support on win 10.  Thanks


Does Quine's dissolution of the Analytic/Synthetic distinction challenge mathematical realism?

I was surprised to learn that Quine is a mathematical realist (). I always assumed that his "Two Dogmas of Empiricism" and specifically his dissolution of the Analytic/Synthetic distinction was a strong challenge to mathematical realism. My reasoning was the following:    (a) Quine shows that what seemed like a perfect example of analytic proposition "all Bachelors are unmarried" is actually based on empirical data inferred from the way the word Bachelor is used. There are possible worlds where "Married bachelor" is a valid statement.  (b) Based on the same reasoning "Odd numbers aren't divisible by 2" can also be considered an empirical statement, and there are possible worlds where "There are Odd numbers divisible by 2" is a valid statement.    Quine later in the paper argues that even the laws of logic are themselves subject to potential change based on empirical data. The way I understand it, this, along with the reasoning in (b), would seem to indicate that math is arbitrary. Based on different empirical data and suitably chosen axioms of logic, just about any mathematical system can be constructed, where statements like "prime that has an integer square root" or  "1+1=3" are completely valid.   Towards the end of the paper, he famously states:      "Physical objects are conceptually imported into the situation as convenient intermediaries not by definition in terms of experience, but simply as irreducible posits comparable, epistemologically, to the gods of Homer . . ."    My questions:    If even the law of excluded middle is subject to revision based on empirical data, then isn't "2+2=4" subject to revision as well?  Is my analogy between (a) and (b) correct? Or even if (a), (b) is still incorrect?  Isn't his stance as a mathematical realist contradicted by the conclusion of the paper?  If even physical objects are posits epistemically on par with Homeric gods, then don't mathematical objects have the same epistemic challenge as well? How can they be real?


Add page number in ACM 2017 SIGCONF Template

I have to number the pages in ACM2017 proceedings and I am using the acmart template. However \pagenumbering... commands and preprint option for document class do not work. Any suggestions?  Edit: I am using sigconfdocument class, which is available on the following website:   and as a minimal example in the following link:


Free Throw Probability and Expected Number of Points

Suppose a basketball player has an 80% chance of making a free throw. The player was fouled and now has two free throws. If a free throw is made it counts as one point. Let X be the number of points from the first free throw and Y be the number of points from the second free throw. Figure out the joint probabilities from X and Y (I've already done this step), the expected number of points from the two free throws and the variance for this number of points if:   a) Each free throw is an independent event   b) P(Y=1|X=1)=.9 and P(Y=1|X=0)=.4 so that making the first free throw raises the prob. a making the second free throw.   All I really need help on is the expected number of points and the variance for that number of points.


Can I ignore files by pattern in deja-dup (Backup)?

My Déjà Dup backups have become quiet large and I noticed they contain a huge number of unnecessary files (e.g. *.pyc files, **__pycache__ folders and other build related temporary stuff).   I know that I can ignore specific folders, but is there a way to exclude files and or folders by patterns?  I thought there might be more options usable trough a configuration file, but Déjà Dup doesn't use one. So I looked at duplicity (the CLI it is based on), but the man page doesn't mention a configuration file either. I know that duplicity can ignore files and folders based on patterns (--exclude, --exclude-filelist), but I have no idea how to combine this with Déjà Dup.  Do I have to ditch Déjà Dup and use duplicity manually? Or is there a way to set the needed options, so that they are used automatically, when duplicity is used by Déjà Dup?


I've been trying to make a java game loop in canvas that runs render(Graphics g) and logic() but it isn't working.  I have already tried making a script that runs the two functions then calls itself again to create a loop.  Thanks in advance.  I tried this:  public class Canvas extends JPanel { static GraphicsDevice gd = GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice(); static int width = gd.getDisplayMode().getWidth(); static int height = gd.getDisplayMode().getHeight(); //Get the system time long lastTime = System.nanoTime(); //Specify how many seconds there are in a minute as a double //store as a double cause 60 sec in nanosec is big and store as final so it can't be changed final double ticks = 60D; //Set definition of how many ticks per 1000000000 ns or 1 sec double ns = 1000000000 / ticks;     double delta = 0;  public static void main(String[] args) {     JFrame frame = new JFrame("Zombie Run");     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);     frame.add(new Canvas());     frame.setSize(width, height);     frame.setVisible(true);     loop(); }  public static void loop() {     logic();     render(g);     loop(); } public static void render(Graphics g) {     System.out.println("Running Render");     g.setColor(Color.BLUE);     g.fillRect(0, 0, 800, 500);  } public static void logic() {     System.out.println("Logic");  }   }  The error I got from eclipse is:  Logic Running Render Exception in thread "main" java.lang.NullPointerException     at ZombieGame.Canvas.render(Canvas.java:41)     at ZombieGame.Canvas.loop(Canvas.java:36)     at ZombieGame.Canvas.main(Canvas.java:31)


London: From Gatwick to the City with an Oyster Card

I am going to London in February and am not sure about all the uses of the Oyster Card. Can I use the Thameslink with an Oyster Card? Even in off-peak times such as 5am or 12 am?


Why doesn't the uncertainty principle stop the formation of a black hole?

I have asked  question. It was supposed to be a duplicate of  one. In that question it is asked if the uncertainty principle can be applied to an already formed black hole. My question is not about the full-fledged black hole but about the formation. It's not about the Pauli exclusion principle either. I just read a question about degeneracy pressure and collapsing white dwarfs. When the dwarfs have a certain mass (say that they have become fat dwarfs) the degeneracy pressure will lose the battle with gravity and collapse to a neutron star. Which in its turn, if it has eaten enough, will collapse into a black hole. All the particles constituting the neutron star will end up at a point, theoretically. Won't the uncertainty principle prevent the last stage of this collapse? Won't some kind of "uncertainty pressure" (not degeneracy pressure) appear? How can particles stay together if their uncertainty in momentum approaches infinity? Or will they always stay a distance apart (in time or in space)?


How to validate email id in alphanumeric

I am trying to validate email to access alphanumeric characters          <script type = "text/javascript"> function checkField(email) { if (/[^0-9a-bA-B\s]/gi.test(email.value)) { alert ("Only alphanumeric characters and spaces are valid in  this field"); email.value = ""; email.focus(); return false; } } </script>   it must contain  alphabets and numerics ex:"test123@gmail.com","admin890@gmail.com" , "abc456@gmail.com"  .. how can rewrite this code.??


Grub_rescue error : unknown filesystem , error loading operating system

I had Windows 7 and Ubuntu 12.04 installed in my system. I removed Ubuntu and installed it again. When I restarted the system, it showed:  Error : Unknown filesystem  grub rescue >    When I use the ls command I am getting this   (hd0),(hd0,msdos8),(hd0,msdos7)(hd0,msdos6)(hd0,msdos5) (hd0,msdos4)(hd0,msdos3)(hd0,msdos2)(hd0,msdos1)   But when I run ls (hd0)/ it's saying unknown partition. The same case for all the others (hd0,msdos1) to (hd0,msdos8).  I tried booting a new OS from USB, and I am getting   Error loading operating system   I also tried Super Grub from USB, but I still get the same error Error loading operating system.  Please let me know what to do now.


Does the down voting of questions and answers on the Meta site serve as a mechanism to discourage the free exchange of ideas by more vocal members? I'm aware that many might consider this a duplicate question, but since this is yet to be resolved IMO it is worth asking. Opinions change, members changes, lets get the latest from the membership. Encouraging everyone to say Yes, No, or Maybe and provide a short explanation. Related: