I applied the subdivision modifier a while ago. But Blender can't take it anymore I really need to undo it! I already start over a bit with the project but I really do not feel like making the wings all over again and the hair....can someone help me?

I am wondering if there is a modifier or tool that will essentially undo a subsurf or subdivide command.


I've got a series of conditional select elements that uses .load to insert dynamic content from an external file. The problem is it fires for the first element only and any subsequent instances result in no action.  I started off with this:  jQuery(document).ready(function($) {   $('#autocad-level-1').change(function() {      var cat_id = $(this).val();     console.log('Category Selected');     $('#autocad-level-2-container').load('http://website.dev/wp-content/themes/dmi/ajax/autocad-level-2.php?cat_id='+cat_id);  });  $('#autocad-level-2').change(function() {      var p_id = $(this).val();     console.log('Product Selected');     $('#autocad-level-3-container').load('http://website.dev/wp-content/themes/dmi/ajax/autocad-level-3.php?p_id='+p_id);  });  });   Research suggested I should use .on as the event handler, but I had no success with that either.  jQuery(document).ready(function($) {  $('#autocad-level-1').on("change", "select", function() {      var cat_id = $(this).val();     console.log('Category Selected');     $('#autocad-level-2-container').load('http://website.dev/wp-content/themes/dmi/ajax/autocad-level-2.php?cat_id='+cat_id);  });  $('#autocad-level-2').on("change", "select", function() {      var p_id = $(this).val();     console.log('Product Selected');     $('#autocad-level-3-container').load('http://website.dev/wp-content/themes/dmi/ajax/autocad-level-3.php?p_id='+p_id);  });  });   This is my HTML:
     <select id="autocad-level-1" name="autocad-level-1">       <option value="0">Select</option>       <option value="1">Option 1</option>       <option value="2">Option 2</option>       <option value="3">Option 3</option>       <option value="4">Option 4</option>       ...     </select>

   What am I doing wrong here? I'm out of ideas.

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


I have a question that I am quite sure does not belong to SO: it is a general, broad question about programming language implementation.  Also, I do not feel it belongs to CS, because it is not strictly computer science (it is more of an engineering question). To be honest, after reading  I was leaning towards CS, but then in the CS FAQ I read "(avoid questions where) there is no actual problem to be solved"  In general, I wonder where to go for questions that:   are not about theory (for those, I would go to cs.stackexchange) are not really practical programming problems (for those, I would go to SO) are not design questions (programmers)   The question I am referring to are something like "Are function calls always implemented using a stack?" "Under which conditions can I transform a function call into CPS, and how would I do that?" (general, not related to a particular piece of code).  Where do questions about programming "curiosities", where there is no actual problem to be solved belong? Or maybe they do not belong to stackexchange at all?

Is there a general discussion section for curious questions? Or are we simply left to swallow such curiosity because the results of it may or may not benefit a big crowd? Sample question There's an idiom, "It costs a moon". As of now NASA hasn't revealed if the Moon has precious elements. This brings some curious thoughts to me... What if the Moon has precious metals, gas, etc.? Does anyone own the moon or other planets in our solar system? Like Americans? Russians, Germans, Japanese, Chinese or British? Are there any constitutions that refrain anyone from such access or ownership to solar elements (either research wise or commercial wise)?


I'm having some difficulty with the following problem.      Let $p$ be a prime integer, and if $a\in\mathbb{Z}$, write $\overline{a}$ for the coset of $a$ in $\mathbb{Z}_{p}$. Show that there is an isomorphism of rings $$\frac{\mathbb{Z}[X]}{\left\langle p, X^{2}+1\right\rangle}\cong \frac{\mathbb{Z}_{p}[X]}{\left\langle X^{2}+\overline{1}\right\rangle}\cong \frac{\mathbb{Z}[i]}{\left\langle p\right\rangle}.$$   Seeing any isomorphism of rings in which we mod out by ideals immediately makes me think that I should be using the First Isomorphism Theorem for rings. However, I'm not sure exactly what maps I should be using between the rings. I think that we could take an evaluation morphism between the first and second rings, but I'm not positive. I'm also confused slightly as to what the ideal $\left\langle p, X^{2}+1\right\rangle$ looks like (that is, the form of a typical element in the ideal is). Thanks in advance for any help!

I am asked to describe the quotient ring $\,\Bbb{Z}[X]/\langle X^2+1,2\rangle$ in two different ways. I would say that $\Bbb{Z}[X]/\langle X^2+1,2\rangle$ is isomorphic to $\Bbb{F}_2[X]/\langle X^2+1\rangle$ and $\Bbb{Z}[i]/\langle 2\rangle$ but I am not sure how can I justify that. Does we have $\langle X^2+1,2\rangle=\langle X^2+1\rangle\langle2\rangle$? I think the answer is no, because $\langle X^2+1,2\rangle=2P(X)+(X^2+1)Q(X)$. How can I justify the two isomorphism ?


Is there a difference in terms of performance between:  Example 1:  function abc(x,y){   return x + y; }  abc();   Example 2:  abc();  function abc(x,y){   return x + y; }   Example 3:  var abc = function(x,y){   return x + y; }  abc();   Which is better and what are the pros and cons of each?

I've recently started maintaining someone else's JavaScript code. I'm fixing bugs, adding features and also trying to tidy up the code and make it more consistent.  The previous developer used two ways of declaring functions and I can't work out if there is a reason behind it or not.  The two ways are:  var functionOne = function() {     // Some code };     function functionTwo() {     // Some code }   What are the reasons for using these two different methods and what are the pros and cons of each? Is there anything that can be done with one method that can't be done with the other?


I have a legacy table with a name containing non-printable characters (CHAR(31), to be specific).   The non-printable character is beside a underscore, and I've discovered that the shortcut CTRL+SHIFT+_ creates the CHAR(31) character (which means "US" - Unit Separator). The previous developer could have hit this combination by mistake, and created the table with this weird character in it.   When we issue a SELECT command against the table, it returns results. But when we try to issue any DDL against it (DROP, sp_rename, etc), the character causes a problem.  Examples:   DROP TABLE Table_Name;   Raises:     Msg 15225 - No item by the name of 'Table_Name' could be found in the current database 'MyDB', given that @itemtype was input as '(null)'.   EXEC sp_rename N'Table_Name', N'NewTableName';    Raises:     Msg 102 - Incorrect syntax near '_Name'.    I already duplicated the table with the correct name, and have corrected it on the dependent objects. The remaining step is just dropping it from the database.   Just an insight: when we copy+paste from SQL Server to Notepad++, it shows the hidden character ("US") on the middle of the table name, beside the underscore:

$sql = "SELECT Kill FROM tbl_pvporderview";   Problem is that I end up with: Incorrect syntax near the keyword 'Kill'.  Because kill is a T-SQL command... any way to bypass it?  I can't change the column name because it's used by the software a lot and I cant change the software that's using the database.  So it simply fails if I use sqlserv to select data from that column. '' or "" wont help.  The complete statement would be:  $sql = "SELECT serial,Kill FROM tbl_pvporderview WHERE Kill > (?) ORDER BY Kill DESC ";


We have a sequence $g_0=3$ and $g_n=2+g_0g_1g_2...g_{n-1}$ for $n\in \mathbb{N}$. How can I prove that $\gcd(g_k,g_n)=1$ if $k<n$? I know that this essentially asking to prove that they are relatively prime, but I am unsure where to begin. Could I show that all of the numbers in this sequence are relatively prime?

A Fermat number $F_n$ is of the form $F_n = 2^{2^n} + 1$  Furthermore, $F_n = 2 + F_0F_1F_2......F_{n-1}$ Now I already proved that  if $n \neq m$ then $\gcd(F_n,F_m) = 1$  Here is the proof  Without loss of generality , I assume that $m > n$ then we know that $$F_m = 2 + F_0F_1F_2........F_nF_{n+1}.....F_{m-1}$$ I assumed here that $n > 2 $ and $n < m-1$  Now we assume that $\gcd(F_n,F_m) = d$ then $d \mid F_n$ and $d \mid F_m$  Now if $d \mid F_n$ then $d \mid F_0F_1.....F_nF_{n+1}...F_{m-1}$ and so $d$ divides any linear combination of $F_m$ and  $F_0F_1.....F_nF_{n+1}...F_{m-1}$, In particular $d \mid Fm- F_0F_1.....F_nF_{n+1}...F_{m-1}=2$ and hence $$d \mid 2$$  Now since all Fermat numbers are odd then $d \neq 2$ and hence $d=1$  Now I want to use this to prove that there exists infinitely many primes.  I know that since Fermat numbers form an infinite sequence of increasing numbers and each Fermat number is relatively prime to all other Fermat numbers then we have infinitely distinct prime divisors for each composite Fermat numbers and we also add to those Fermat prime numbers.  I feel like there is a better mathematical argument that that novel that I wrote above :)


\documentclass{article} \begin{document} Test\footnote{Test} \end{document}   Now it like this:     And I want this:

This question led to a new package:      How can I get footnote or endnote text to appear right after the paragraph in which it was mentioned?  Update:  As my question lacks sufficient detail, I'll try to clarify.   The goal is to place the notes closer to the reader and to have a document which flows from start to finish, rather than one that is interrupted continuously by footnotes. By "footnote" or "endnote", I mean anything with a cross-reference mark (e.g. "1") pointing to another place on the page (the end of the paragraph).   Update:  The provided answer greatly solves the initial problem quite well. It is, however, incompatible with a number of other options provided by addition packages, such as footmisc and its included options such as para and stable. The bounty will go to an extended solution which:   Provides the ability to define the mark and text in different locations so that footnote marks can be placed within section titles (see footnotemark and footnotetext and stable options in footmisc for an example). E.g.:  \begin{footnotepar} \section{This is a section title\footnotemark}     \footnotetext{This is the text for a footnote which has a mark in the section title.}     This is text in the paragraph. \end{footnotepar}  Treats the footnote text as if it is no different from text within a standard paragraph and allows the text to behave in a similar manner (e.g. flowing into a paragraph, breaking at the end of the page). E.g.:      1 This is the text of the first footnote.  2 This is the text of      the second footnote. 3 This is the text of the third footnote.      4 This is the text of the fourth footnote. 5 This is the text of        the fifth footnote which partially appears on the top of the      second page. 6 This is the text of the sixth footnote.    Leaves points for uniformly controlling the size, font, and position of the footnote mark (the one appearing near the footnote), the footnote text itself, and the space after each footnote (e.g. placing \newline to go to a new line, or \hspace to add some space). Leaves points for uniformly enclosing an environment around each group of footnotes, for e.g., to enable the groups of footnote texts to be enclosed with \begin{multicols}{2} and \end{multicols} (or other environments).


I just built the lake view manor and it is fully furnished. I have 2 children's beds and chests. My husband gave me the option to move to the new location, but my kids don't have that option. Is there something else I need?

I have my first house in Whiterun, and I built a children's room there. I also have Lakeview Manor and built the children's beds and chests there too. Now I'm attempting to adopt, and the only home I can put a child in is the house in Whiterun. I would prefer to use my other home though. Is there a way to change which house they go in?


Do you know of a way to enter a file directly from the MXD extension QGIS? Is this possible? How about MapPackage files? I do not have access to the ArcMap software. Best Regards.

I recently tried to use QGIS and I wondered if you can convert a draft ArcGIS map (*.mxd file) into a QGIS project (*.qgs file).   This would avoid thematize the entire project.


I wish to upgrade from Snow Leopard (10.6.8) to anything higher.  Disk Utilities repair says the disk needs to be repaired.  So, I need to boot onto something other than the boot drive to run disk utilities.  I downloaded El Capitan from the App Store.  It appears to be an install app.  I tried , but it requires 10.7 or higher.  Not sure how to make a bootable image from the install app in Applications.  I can't use OS X Recovery, that also requires 10.7 or higher.   require the DVD media, which my parents likely never had.  All the   found for bootable USBs require a disk image.  Any options?  Edit 1: I created a USB drive using , "Option 2: Use Disk Utility."  I modified a bit (El Capitan instead of Yosemite, got the BaseImage.dmg by copying and using xattr to remove the invisible bit, ..), but I have a USB key with "Mac OS Extended" format and 7.8G of stuff on it.  When I boot up holding down the option key, it doesn't show any menu to choose where to boot from, it just ignores my USB drive.  When I open the "Startup Disk" system preferences dialog, it does not show the USB drive (even though it is mounted).  It is plugged directly into this mac mini, not through a hub or keyboard.  I looked around for related questions (e.g., ), and found nothing relevant.  Any idea of how to debug a USB drive being ignored upon (Snow Leopard) startup?

Does anyone have a Terminal command-line recipe for making a new bootable USB flash drive for one of the new MacBook Air's?  Is there a way to dd copy the USB boot device that comes in the box and make the new copy bootable?  I'd like to make a new backup copy of the USB rescue device for my MBA, preferably on a much larger flash drive with room for a backup of some of my working directories.  Added:  And is it possible to make, not just a rescue drive, but a bootable USB drive that will boot a fully updated version of the OS (say 10.6.8 or later)?  If so how on a MacBook Air 11, and how big a USB stick will this require?


I have got "localhost/management". I have got my site for customers: "localhost/website". So I got 2 websites (one for management, one for customers). Now I have made a javascript which causes to show a popup onload. The javascript is included into the customer side. Now what I need to do is make an HTTP request from my javascript to the management side (which is connected to database) and get a value from that. So when a value is (1 - show popup at customer side) (0 - not show popup at customer side). The value has to come from the database. When I'm at the management side and when I made some changes (like updating info) then the value has to change too. I'm working with localhost.

I need to do an  request in JavaScript. What's the best way to do that?  I need to do this in a Mac OS X dashcode widget.


I'm a little conflicted as to why we consider $\vec{a}^T\vec{b}$ to be the same as dot product $\vec{a}\cdot\vec{b}$ is some calculations, where both $\vec{a}$ and $\vec{b}$ of let's say size $n\times1$. We know that $\vec{a}\vec{b}^T$ results in a matrix of size $n \times n$, shouldn't $\vec{a}^T\vec{b}$ result in a matrix of size $1 \times 1$? In comparison, $\vec{a}\cdot\vec{b}$ is a scalar. I feel like I'm missing some kind of convention?

I am learning linear algebra, and I am a bit confused by the dot product and how the answer to the process turns out to be a scalar rather than a matrix.  For $2$ vectors with $2$ components, I learned that dot product is equivalent to a $1 \times 2$ row vector left multiplied by a $2 \times 1$ column vector.   The result of such a multiplication should result in a $ 1 \times 1 $ vector.   But I am learning that the dot product somehow transforms the result into a scalar, rather than a $ 1 \times 1 $ vector.  Maybe I am missing something but the difference between a $ 1 \times 1 $ vector and a scalar seems important, because you can multiply a scalar by a matrix of any size, but you can only left-multiply a $ 1 \times 1 $ vector by another matrix with $1$ row.  Thanks for any help in understanding this.


is it possible to have a skewed orthogonal perspective camera? I want to make a perspective like in the old ultima games where the x and y axis are aligned with the screen and the z axis is at a 45 degree angle. Essentially the same question has been asked before here:  However sadly I can't use the proposed solutions there. I cannot shear the image after rendering because I need the image to be pixel perfect. Also I cannot transform the rendered model because that will mess with the lighting. Ideally, I'd like to be able to enter the view transform matrix of the camera directly myself. Can this be done somehow, maybe via scripting?

For the start, I thought was orthographic, but when I used the orthographic camera, it didn't match up. Client say they want a so-called "industry schematic", talking about a 135 degree look.  I found a trick to do this, which is using lattice. I align the lattice with the cube, and move the upper four points a little bit along the axis showing on the following image. But I want to achieve this by just using the camera.


I'm having an interesting (albeit frustrating) issue with Python.   I'm attempting to populate a 2d array called plaintexts based on some calculations, and I've found that all of the entries in this array are duplicated. Ie, plaintexts[0] == plaintexts[1] == ... == plaintexts[n]. I assumed I messed up value assignment so I tried to halve my code to find the issue, but after a fruitless hour I assigned a value to plaintexts[0][3] at the end of my code and lo and behold, that same value popped up in every other row.   Below is my relevant code:  placeholder = ['0'] * 33 plaintexts = [placeholder] * len(ciphers)  for i in range(2):      for j in range(1, 2):          for k in range(0,len(ciphers[0])-1,2):             .             .             .             .             if charType == '010':                 if(plaintexts[i][k/2] != '0'):                    .                   .                   .                   .                 else:                     plaintexts[i][k/2] = (' ', xorstr.lower())                   .                   .                   .                   .  plaintexts[0][3] = '13414113133' print plaintexts[0][3] print plaintexts[1][3] print plaintexts   I'd appreciate any help in figuring out the issue.

I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


"I don't think they can go with us, can't they? / can they?" Which one is correct?

He did nothing*.   Which is the correct question tag for the sentence above?   didn't he? did he?   What is the effect of using nothing for negation?


What is the difference between 2*a and 2a? What is the difference between  2(3+4) and 2*(3+4)?  We all know that omitting the multiplication sign still means multiplication so nothing changed!  This question is related to a well-known mathematical debate as follows: 6/2(1+2) If we use the rule of order of operation which states that : Parentheses first, exponents next, multiplication and division from left to right and finally addition and subtraction from left to right The result will be 9 However, some would say that 6/2(1+2) is like 6/(2(1+2))  Having mentioned that they would say what is the result of 9a^2/3a?  I know this question might be "duplicate" or whatever... But I really searched a lot and didn't find a satisfying answer.  Is 3a the same as 3*a or (3*a)?  So 9a^2/3a = (9*a^2) / (3*a) Or 9*a^2/3*a

Given $5x/30x^2$ I was wondering which is the correct equivalent form.  According to BEDMAS this expression is equivalent to $5*\cfrac{x}{30}*x^2$ but, intuitively, I believe that it could also look like: $\cfrac{5x}{30x^2}$  I asked this question on MathOverflow (which was "Off-topic" and closed) and was told it was ambiguous. I was wondering what the convention was or if such a convention exists. According to Wikipedia the .


I  created a search method for a linked list.  It works correctly when I search for something that does exist in the list.  If I search for something not in the list, then I get a null pointer exception.  I don't see how its possible to get this exception.  Here is the method:   // these two search methods return the node containing the substring given public UNode search(String cityName) {     return search(cityName,this);//line 90 }//end search()------------------------------------------------------------- private UNode search(String cityName, UNode current) {     if(current != null)     {         if (current.getCity().getName().contains(cityName))         {             System.out.println("Node '" + current.getCity().getName()                      + "' has been found and returned.");             return current;         } else         {              return search(cityName,current.next);//line 105         }     }     else     {         System.out.println("No node containing the substring '"                  + cityName + "' can be found, returning null");         return null;     } }//end search()-------------------------------------------------------------   To my understanding, this is what happens when searching for something that does not exist:  The method keeps calling search() recursively with current.next, it gets to the last element and calls search(cityName, null), then since current is null, it says it is not found, and returns null.  Am I missing something here?  What am I doing wrong?  Should I just throw the null pointer exception?  Here is the method where I call the search method:  public static void uNodeTest(City[] cities) {       UNode unvisited = new UNode();      unvisited.addCities(cities);       String a = unvisited.getNext().getNext().getNext().getCity().getName();      System.out.println(a);      UNode current = unvisited;     while(current.getNext() != null)     {         System.out.println(current.getCity().getName());         current = current.getNext();     }     UNode phil = unvisited.search("not a city"); }   Stack Trace:  java.lang.NullPointerException at cityproject.UNode.search(UNode.java:105) . . . at cityproject.UNode.search(UNode.java:105)//(omitting repeats) at cityproject.UNode.search(UNode.java:90) at cityproject.CityProject.uNodeTest(CityProject.java:104) at cityproject.CityProject.main(CityProject.java:79)

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


First question, am I seeing this slang correctly? amint I Second, is there an alternative way I should say it? And if not, how would you write it? "Well yeah, I’m standing here amint I?"

Why do we say "ain't I" or "aren't I" instead of "amn't I"? What's the history of this usage? Are there any other similar patterns in English?  I'm guessing it has something to do with the dispreference of two consecutive nasal consonants, but a more authoritative answer would be great.


I used the command poweroff and unexpectedly the system went off. I didn't used sudo therefore I didn't expect computer to be turned off. Why it was possible for me to use this command without root privilege?

For some reason, I can run halt, poweroff, shutdown, and reboot as a regular user without root. How can I fix this? Is it something to do with user groups, or is it a seting somewhere?


how to generate a long that is in the range of [0000,9999] (inclusive) by using the random class in java? The long has to be 4 digits.

How do I generate a random int value in a specific range? I have tried the following, but those do not work: Attempt 1: randomNum = minimum + (int)(Math.random() * maximum);  Bug: randomNum can be bigger than maximum. Attempt 2: Random rn = new Random(); int n = maximum - minimum + 1; int i = rn.nextInt() % n; randomNum =  minimum + i;  Bug: randomNum can be smaller than minimum.


Find the value of $\csc^2 \pi/7 + \csc^2 2\pi/7 + \csc^2 3\pi/7$  My try : Converted it into Sin and then tried to apply series formula but failed

What is the value of $$\textrm{cosec}^2\left(\frac\pi7\right) +\textrm{cosec}^2\left(\frac{2\pi}7\right)+\textrm{cosec}^2\left(\frac{4\pi}7\right) \qquad\qquad ? $$  I tried to write $\textrm{cosec}^2\left(\frac{4\pi}7\right)$ as $\textrm{cosec}^2\left(\frac{3\pi}7\right)$. Then converted in $\sin$... But in vain.. Is there any other approach?


Is a field just a commutative ring?  My algebra professor didn't give a very wide introduction to this algebraic structure, and I did not get a real grasp of what a field is.  We're studying polynomials of $\mathbb{K}[x]$ and he keeps repeating $\mathbb{K}[x]$($\Bbb{C}[x], \Bbb{R}[x] $ or $\Bbb{Q}[x]$) are fields so they have $y$ or $z$ property, but I don't get the difference between them and a commutative ring.

The ring axioms require that addition is commutative, addition and multiplication are associative, multiplication distributes over addition.   A field can be thought of as two groups with extra distributivity law.   A ring is more complex: with abelian group and a semigroup with extra distributivity law.  Is a ring a more basic structure than a field, or vice versa? What's the relation between them? What's the background why people study them?


My website changed significantly this month.  Amongst the changes was the website's title.  Two weeks ago, I finally used Webmaster Tools and submitted the page.  So far, Yahoo and Bing have updated the title in the search results, but not Google.  I've resubmitted via Webmaster Tools the website, and the bots have crawled the page, and have added "content keywords".  But the title still doesn't match.  The "content keywords" lists many of the words in the new title (but contains keywords of the existing title also).  Must say that 4 of the top 5 key words in the "significance" list are the new title's.  Still, no change.  Any remedies for this problem?  Is adding the "alt" tag for the logo significant enough to trigger the change?  There isn't an appropriate place to put the company name between  tags on the front page.  Any suggestions?  Thanks.

I'm just wondering how it is possible that IGN.com has this in its title tag:      Video Games, Cheats, Walkthroughs, Game Trailers, Reviews, News, Previews & Videos at IGN   while on Google its title is simply "IGN".   How can one achieve such a thing? Does it use some special meta tag I can't see?


Prove that for an arbitrary (possibly infinite) language, that for a finite L-structure $M$, if $M \equiv N$ then $ M \cong N$   I'm struggling to think of what to do, I presume the best thing is to keep it simple and assume the Language to only be relational.  I'd start by assuming we have a finite Language and taking $|M|$ = k = $|N|$ and as I've assumed the language to only be relational and finite take {$R_1,...,R_p$} to be the relation symbols. I'm guessing I need to show that there is some sentence $\sigma$ that is true in both $M$ and $N$? I have no idea what that sentence would be could someone help me out? Thanks.   Also how would I even begin to answer it in the infinite case?

I am trying to prove that if $T$ is a complete first order theory that has a finite model then it has exactly one model up to isomorphism. To this end, I assumed that $T$ is complete with a finite model $M_n$. Then I assumed that $M_m$ was another model of size $m \geq n$. We know that if a theory has two finite models with different cardinalities then the theory is incomplete hence $m = n$. Now two things remain to be shown: one is that any two models of finite size $n$ are isomorphic and the other is that every infinite model is also isomorphic to this finite model (is this even possible? but we clearly need to do something about the infinite case)  Thanks for helping me finish this proof. For the record: this is an exercise in Just/Weese, page 84.  Edit  I'm looking for a sentence $\varphi$ such that if $M_n \models \varphi$ then $M_n \cong M_m$. There are no assumptions on the language. But I think it's not possible to have a finite model for an infinite language so the language must be finite.   Edit 2  After some more thinking, if there is a finite model $M$ of size $n$, let $$ \varphi = \exists v_1, \dots , v_n ((v_1 \neq v_2) \land \dots \land (v_{n-1} \neq v_n)) \land \lnot \exists v_{n+1} ((v_{n+1} \neq v_1) \land \dots \land (v_{n+1} \neq v_n))$$ that is, $\varphi$ says that the model has exactly $n$ elements. Since $T$ is complete, either $\varphi$ or $\lnot \varphi$ is provable from $T$. Since we have a model in which $\varphi$ is true we therefore know that $T \vdash \varphi$. Hence any model of $T$ must have exactly $n$ elements.   Now the question is, how do I show that any two $n$-element models of $T$ must be isomorphic?


Let $a>0$ and $f:[0,a] \to \mathbb{R}$ continuous function that is twice differentiable on $(0,a).$ Also $f(0)=0$ and $f'$ is strictly increasing function on $(0,a).$   I have to show that the function $g$ defined as $$g(x) = \frac{f(x)}{x}$$ is strictly increasing on $(0,a].$    Progress: I computed $g'$ and got $g'(x) = \frac{f'(x)x-f(x)}{x^2}.$ I have to show that $g'(x)>0 \ \ \forall x \in (0,a].$  Since $x^2$ is always positive for $x \in (0,a]$ I have to show that $f'(x)x-f(x) >0 \ \ \forall x \in (0,a].$ I know both terms are positive, but I don't know how to show that $f'(x)x>f(x) \ \ \forall x \in (0,a].$

Suppose $f$ is a differentiable function over $\mathbb{R}$ satisfying $f(0) = 0$. Show that if $f'$ is strictly increasing, then $\frac{f(x)}{x}$ is increasing over $(0,\infty)$.   Attempt:  Since $f'$ is increasing we know that $f'' > 0$ for all $x$. Now let $g(x) = \frac{f(x)}{x}$ and thus $f(x) = xg(x)$. Then we wish to show that $g'(x) > 0$ on $(0,\infty)$ and so since $f'(x) = xg'(x)+g(x)$ and $f''(x) = xg''(x)+2g'(x) > 0$, we have $g''(x) > \frac{-2g'(x)}{x}$. I am not sure how to use this though to prove the statement.


Unable to create environment variables using a tcsh script.  Tried set, but works only inside the script. setenv doesn't work outside the script. export says "command not found" in the terminal I'm trying to run.  #!/usr/intel/bin/tcsh #set WV "/p/hdk/cad/custom_waveview/O-2018.09-SP2/bin/wv" setenv WV "/p/hdk/cad/custom_waveview/O-2018.09-SP2/bin/wv" echo $WV env $WV "/p/hdk/cad/custom_waveview/O-2018.09-SP2/bin/wv"   I expect the output to be /p/hdk/cad/custom_waveview/O-2018.09-SP2/bin/wv, when i echo the environment variable WV on the terminal, but i am getting the error of undefined variable.

I'm trying to write a shell script that, when run, will set some environment variables that will stay set in the caller's shell.  setenv FOO foo   in csh/tcsh, or  export FOO=foo   in sh/bash only set it during the script's execution.  I already know that   source myscript   will run the commands of the script rather than launching a new shell, and that can result in setting the "caller's" environment.  But here's the rub:  I want this script to be callable from either bash or csh.  In other words, I want users of either shell to be able to run my script and have their shell's environment changed.  So 'source' won't work for me, since a user running csh can't source a bash script, and a user running bash can't source a csh script.  Is there any reasonable solution that doesn't involve having to write and maintain TWO versions on the script?


I have got a problem with executing a submission of dynamically added (by function) with two scripts in HEAD.  My HTML is:  <html> <head> <title>Web Page</title> <script src="js/jquery.min.js"></script> <script src="js/script.js"></script> <script src="js/forms.js"></script> </head> <body> <div id="container"> </div> </body> </html>   So when I dynamically by function adding a form into  and trying to submit the data it doesn't work. All required code for execution the form is in js/forms.js I suppose it doesn't see the dynamic objects.  The form which is being added dynamically looks like (with jQuery code):  $('#container').append("<form class='input-form'><input type='text' id='login' /><input type='password' id='password' /><input type='submit' /></form>");   And the script is:  $('form.input-form').on('click', '#sendbutton', function () { preventDefault(); var value_login = $("#login").val(); var value_password = $("#password").val(); alert(value_login + value_password); });   Would anybody suggest how to make it working in jsfiddle? Or what I am doing wrong?  The real example here:

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


Compiler can't find 'polish' package. - I have no idea what is happening, I was editing the same document a week ago and everything worked perfectly fine. Another error that occurs is "l. 299 \ProcessOptions*". I am quite new to LaTeX so would appreciate your help. (I use TeXworks)

I recently updated my operating system from Ubuntu 13.04 to Ubuntu 13.10. Since then, I am facing difficulties compiling my TeX code in which the french babel package is called. Please note that all my sources were compiling very fine before the system upgrade. However, now, given the following header:   \usepackage[francais]{babel}  I receive the following error:  ! Package babel Error: Unknown option `francais'. Either you misspelled it   What should I do? Please note that if I remove this part of code (\usepackage[francais]{babel}), everything is compiling well. I also tried it with french, and I receive the same result. Thank you in advance for your help.  MINIMUM WORKING EXAMPLE : \documentclass[11pt,a4paper]{article} \usepackage[utf8]{inputenc} \usepackage[francais]{babel} \usepackage[T1]{fontenc} \usepackage{amsmath} \usepackage{amsfonts} \usepackage{amssymb}  \begin{document} This is a MINIMUM WORKING EXAMPLE. \end{document}   ! Package babel Error: Unknow option `francais'. Either you misspelled it


Assume that $f(x)$ and $g(x)$ are both continuous real functions, and that, for $x \ne 0$, $f'(x) = g(x)$.  Is then $f(x)$ differentiable at $x = 0$, with $f'(0) = g(0)$?

Let $f$ be a real-valued function continuous on $[a,b]$ and differentiable on $(a,b)$. Suppose that $\lim_{x\rightarrow a}f'(x)$ exists. Then, prove that $f$ is differentiable at $a$ and $f'(a)=\lim_{x\rightarrow a}f'(x)$.    It seems like an easy example, but a little bit tricky. I'm not sure which theorems should be used in here.    ==============================================================  Using @David Mitra's advice and @Pete L. Clark's notes I tried to solve this proof. I want to know my proof is correct or not.  By MVT, for $h>0$ and $c_h \in (a,a+h)$ $$\frac{f(a+h)-f(a)}{h}=f'(c_h)$$ and $\lim_{h \rightarrow 0^+}c_h=a$.    Then $$\lim_{h \rightarrow 0^+}\frac{f(a+h)-f(a)}{h}=\lim_{h \rightarrow 0^+}f'(c_h)=\lim_{h \rightarrow 0^+}f'(a)$$   But that's enough? I think I should show something more, but don't know what it is.


I'm using an environment called Greenfoot, a simple Java based 2d game engine, however I do not think the issue is related to Greenfoot, but java in general. In Greenfoot, there is a World class, in which all of the Actors (just objects) interact with each other. Whenever you create the World (it is constructed each time you start the game) you are actually creating a MyWorld object, which extends world and you can write your own code into. My specific game is Chess, and my problem is related to the enpassant rule. All of my chess pieces are children of one super class Piece which in turn is a child of the Greenfoot class Actor. For every piece except the pawn, they use the method in Piece makeMove(x, y), shown here. protected void makeMove(int x, int y) {     MyWorld w = (MyWorld)getWorld();     if(canMove(x, y))     {         w.mainBoard.movePiece(getX(), getY(), x, y);         w.makeMove();         w.displayBoard();         w.setEnPassant(-1);     } }  The first line gets the world the object is in, using the getWorld() method. Since getWorld() returns an object of type World, but my actors are in the object of type MyWorld, I just use casting. There is no scenario in which getWorld() will be called and a MyWorld will not be returned. Nothing else here is super important, it just checks if it is possible to make the move fed to it, and if so, all of the code inside just moves the piece and updates the board, all of this works. Also, setEnPassant sets a variable stored in the MyWorld object to -1, I use this variable to tell if enPassant is a possible move or not, and I reset the value in makeMove since makeMove will be called every turn. The problem comes from the Pawn class, which extends Piece. To make enPassant work, I have to override the makeMove method inside of Pawn, see here: protected void makeMove(int x, int y) {     int y1 = getY();     super.makeMove(x, y);          if(Math.abs(y1 - y) == 2)     {         MyWorld w = (MyWorld)getWorld();         w.setEnPassant(getX());     } }  First, I store the current y value (the up and down coordinate). Then, I call super.makeMove(x, y), which moves the piece to its new spot. Next, I have an if-statement which checks whether or not the pawn moved 2 squares. The only time this can happen is at the very beginning, and if the pawn does move two squares it attempts to set the enPassant value to whichever column it is in. This is essentially broadcasting "I am available to be en passanted," and if there is a pawn on the other side who is in the proper spot, it will see that there is an en passant it can make. The problem I am having is only on the very last line. Defining MyWorld w works, but calling setEnPassant() throws a NullPointerException. In fact, any method I call here throws a NullPointerException. No matter what I do with the object w, a NullPointerException is thrown. I've done a few things which patch the issue, like for some reason moving super.makeMove(x, y) to the end of the method causes no problems. However, I need it to be at the beginning so that it does not immediately reset the EnPassant value to -1. Another very strange solution I found was by changing the return type of makeMove in both Piece and Pawn to MyWorld. In Piece, I return the world w, and in Pawn, I use that same world w to set the en passant value. So instead of saying MyWorld w = (MyWorld)getWorld();  I write MyWorld w = super.makeMove(x, y);  There may be some more elegant ways of handling en passant but I don't really want to hear about any of those. Really I would just like to know why there's an error here and not in other places, and why the strange fixes I found made it not throw the NullPointerException.

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


can anyone help me to prove that $Z := \{(x, y, z) ∈ R^3 | x^2 + y^2 − z^2 = 0\}$ is not a manifold (even it is not a topology manifold)?

Prove that:  $$Z:=\Big[ {(x,y,z) in $R^3$|x^2 +y^2-z^2=0}\Big]$$  is not a manifold.(Even It is not a topology manifold )


If $R$ is a UFD and $f \in R[x]$, then we can't always use Eisenstein's Rule directly to show that $f$ is irreducible in Frac$(R)[x]$. However if we have $\phi$, an automorphism of Frac$(R)[x]$, then $f$ is irreducible if and only if $\phi(f)$ is irreducible. In order to apply Eisenstein to the resulting polynomial, you need $\phi(f) \in R[x]$, then you can deduce that your original $f$ was irreducible (we are using a 'shifted' version of the rule).  For example, for the cyclotomic polynomials $x^{p-1} + \dots + x + 1$, you cannot use Eisenstein directly, however if you consider $\phi : \mathbb{Q}[x] \rightarrow \mathbb{Q}[x]$ which sends $x$ to $x+1$ and does nothing on $\mathbb{Q}$, then using the binomial the resulting polynomial is Eisenstein at $p$.      What I am wondering is given an irreducible polynomial, can you always find an automorphism such that you can apply Eisenstein to show it's irreducible?   If not in general then what about the case where $R = \mathbb{Z}$ and $\phi$ is an automorphism of $\mathbb{Q}[x]$?

My Question is to check Irreducibility for polynomials not satisfying Eisenstein Criterion.  As an Illustration, to check whether $x^{p-1}+.....+x+1$ for p a prime is irreducible or not, we replaced $x$ by $x+1$ and by using Eisenstein's Criterion for the resulting polynomial we conclude that resulting polynomial is irreducible and so is the original polynomial.  In general, for a given irreducible polynomial $f(x)$ with coefficients in a known U.F.D, is there some element $a$ such that we can apply Eisenstein's criterion to $f(x+a)$?  I am sure there would be no general structure for this but I expect there to be at least some special cases.   Any Reference/suggestion would be appreciated.  Thank You.


I Have to prove that $P(A-B) \neq P(A)-P(B).$ I Know how to prove that $P(A\cap B) = P(A)\cap P(B).$,but not this one. Can someone help me please?Thanks.

I need help proving or disproving this! If anyone could show me the sequence of steps I can use to help me show the left is equal to the right I would be grateful.  $$\mathcal P(A-B)=\mathcal P(A)-\mathcal P(B)$$


When I build a regression model, which is considered most important:   removing insignificant variables, checking jfor multicollinearity and removing those variables that contribute to it, multiple R-Squared, or something else?   If I have to take care of all of the above, what should be my order of preference?  If I want to evaluate the model, is there is hard and fast rule that says residuals should be normally distributed?

In linear regression analysis, we analyze outliers, investigate multicollinearity, test heteroscedasticty.   The question is:  Is there any order to apply these? I mean, do we have to analyze outliers very firstly, and then examine multicollinearity? Or reverse?    Is there any rule of thumb about this?


By definition, a set $S$ is called countable if there exists an bijective function $f$ from $S$ to the natural numbers $N$.  If we take a function $g\colon\mathbb{Z\times N\to Q}$  given by $g(m, n) = \frac{m}{ n} $ to "construct" rational numbers, $g$ would only be a surjection from the countable set $\mathbb{Z\times N}$ to $\mathbb Q$. It's not injective, or is it?

I want to prove that $\mathbb{Q}$ is countable. So basically, I could find a bijection from $\mathbb{Q}$ to $\mathbb{N}$. But I have also recently proved that $\mathbb{Z}$ is countable, so is it equivalent to find a bijection from $\mathbb{Q}$ to $\mathbb{Z}$?


I need to compile file using psfrag ans eps figure. I use texworks on windows and I have read that there are problems with pdflatex and I should go the latex->dvi->ps way but all I have found so far is not at all understandable for me... could you help me please? Thanks by advance :)

I am trying to configure TeXworks to run the following chains:   latex with automatic dvi viewer opening latex+dvips with automatic ps viewer opening   Essentially, I want to learn how to configure TeXworks to create my own chains of commands possibly with a long list of executables that are usable and commands used within TeXworks. That is, what can go under Program and Arguments.  For example, from the post:  if I want to compile via latex+dvips+ps2pdf, I would need to use  -e $latex='latex -synctex=1' -e $dvips='dvips -P pdf -t a4' -pdfps $fullname   with latexmk as the Program as shown below:    When I analyze the pdfLaTeX settings its much simple than the one shown above. Any clarifications on how to create these settings and explanation or tutorials to understand TeXworks at this level will be very helpful. Is latexmk the only Program which can be used? I have tried changing it to latex.exe or the sort but no good results.


My problem is that I have a non-structured .txt file like the one below that contains different links because there is a signature in each link:    What I want is to extract all the links that begins with http:// web.alphorm.com  I used the regex shown below:  matchObj = re.findall(r'(http:// web.alphorm.com/.*&Key-Pair-Id=APKAJF2PMCJPGKXG2GEA)"}',                       string)   But it doesn't really gives me what I want. It shrinks the text file and gives me the searched links, but along with other undesirable links and text!   What is wrong with it?

I have this gigantic ugly string: J0000000: Transaction A0001401 started on 8/22/2008 9:49:29 AM J0000010: Project name: E:\foo.pf J0000011: Job name: MBiek Direct Mail Test J0000020: Document 1 - Completed successfully  I'm trying to extract pieces from it using regex. In this case, I want to grab everything after Project Name up to the part where it says J0000011: (the 11 is going to be a different number every time). Here's the regex I've been playing with: Project name:\s+(.*)\s+J[0-9]{7}:  The problem is that it doesn't stop until it hits the J0000020: at the end. How do I make the regex stop at the first occurrence of J[0-9]{7}?


Can someone tell about how it is possible to write locally finite sets $n_{Z}$  with the free abelian group generated by the prime divisors? First I thought it was a cartesian product of spaces but it is in a free abelian group, so I dont know how to continue. It looks like I use the prime divisors to generate the locally finite subsets, is that all I have to do ?

Could someone be able explain how to add prime divisors or their multiplication with the locally finite set $n_{Z} Z$ in $\sum n_{Z} Z$? .


Let $f, g \in \mathbb{F}_5[X]$ where $f=X^9+X^8+ \cdots +X^2+X+1, g=X^4+X-2$.      (1) Find the greatest common divisor $h$ of $f$ and $g$.      (2) Find polynomials $m,n \in \mathbb{F}_5[X]$ such that $mf + ng = h$.   (1) By using polynomial division, I found out that $h = 3X^2+4X+3$.  I don't know how to approach (2) (systematically), so could somebody please show me how that would work?  Thanks in advance!

I have two polynomials: $f: x^3 + 2x^2 - 2x -1$ and $g: x^3 - 4x^2 + x + 2$. I have to do two things: find $gcd(f,g)$ and find polynomials $a,b$ such as: $gcd(f,g) = a \cdot f + b \cdot v$. I have guessed their greatest common divisor: $(x-1)$, but I did it by looking for roots of both polynomials, and now I am stuck. How do I find the greatest common divisor using the Euclid algorithm? I started with $f(x) = g(x) + 3(2x^2 - x - 1)$, but then things go nuts, and I can't use Bézout's identity to bring it all back to $gcd(f,g) = a \cdot f + b \cdot v$.


df -h   gives:  Filesystem                         Size  Used Avail Use% Mounted on  udev                               3.9G     0  3.9G   0% /dev tmpfs                              799M   81M  718M  11% /run /dev/mapper/buildingbase--vg-root  287G   27G  246G  10% / tmpfs                              3.9G     0  3.9G   0% /dev/shm tmpfs                              5.0M     0  5.0M   0% /run/lock tmpfs                              3.9G     0  3.9G   0% /sys/fs/cgroup /dev/vda1                          472M  466M     0 100% /boot /dev/vdb1                          2.0T  647G  1.4T  32% /mnt/bigstorage tmpfs                              799M     0  799M   0% /run/user/1000   my kernel  uname -r  4.4.0-72-generic   And than my installed kernels...  dpkg -l | tail -n +6 | grep -E 'linux-image-[0-9]+'   as you can see NO OLDER KERNELS :-{  ii  linux-image-4.4.0-72-generic       4.4.0-72.93                                amd64        Linux kernel image for version 4.4.0 on 64 bit x86 SMP ii  linux-image-4.4.0-75-generic       4.4.0-75.96                                amd64        Linux kernel image for version 4.4.0 on 64 bit x86 SMP ii  linux-image-4.4.0-78-generic       4.4.0-78.99                                amd64        Linux kernel image for version 4.4.0 on 64 bit x86 SMP ii  linux-image-4.4.0-79-generic       4.4.0-79.100                               amd64        Linux kernel image for version 4.4.0 on 64 bit x86 SMP ii  linux-image-4.4.0-81-generic       4.4.0-81.104                               amd64        Linux kernel image for version 4.4.0 on 64 bit x86 SMP ii  linux-image-4.4.0-83-generic       4.4.0-83.106                               amd64        Linux kernel image for version 4.4.0 on 64 bit x86 SMP ii  linux-image-4.4.0-87-generic       4.4.0-87.110                               amd64        Linux kernel image for version 4.4.0 on 64 bit x86 SMP ii  linux-image-4.4.0-89-generic       4.4.0-89.112                               amd64        Linux kernel image for version 4.4.0 on 64 bit x86 SMP ii  linux-image-4.4.0-91-generic       4.4.0-91.114                               amd64        Linux kernel image for version 4.4.0 on 64 bit x86 SMP ii  linux-image-4.4.0-92-generic       4.4.0-92.115                               amd64        Linux kernel image for version 4.4.0 on 64 bit x86 SMP   How can I clean up /boot?  Of course   sudo apt-get autoremove   is not working... not enough space

My first issue was when I tried to apt-get update or apt-get upgrade. On upgrade I get the following error:  You might want to run 'apt-get -f install' to correct these. The following packages have unmet dependencies: linux-image-server : Depends: linux-image-3.2.0-27-generic but it is not installed E: Unmet dependencies. Try using -f.   I tried running apt-get install -f and this was the output(after saying yes on prompt)  (Reading database ... 186183 files and directories currently installed.) Unpacking linux-image-3.2.0-27-generic (from .../linux-image-3.2.0-27-generic_3.2.0-27.43_amd64.deb) ... Done. dpkg: error processing /var/cache/apt/archives/linux-image-3.2.0-27-generic_3.2.0-27.43_amd64.deb (--unpack):  failed in write on buffer copy for backend dpkg-deb during `./boot/System.map-3.2.0-27-generic': No space left on device  No apport report written because the error message indicates a disk full error                                                                           dpkg-deb:    error: subprocess paste was killed by signal (Broken pipe) Examining /etc/kernel/postrm.d . run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.2.0-27-generic   /boot/vmlinuz-3.2.0-27-generic run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.2.0-27-generic /boot/vmlinuz-3.2.0-27-generic Errors were encountered while processing: /var/cache/apt/archives/linux-image-3.2.0-27-generic_3.2.0-27.43_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1)   I tried running apt-get autoremove and it gives me the same error as apt-get upgrade.  When I run df, I get this for /boot:  /dev/sda1                    233191     230297         0 100% /boot   So, I read elsewhere that I should try to purge old kernels. I checked for what kernels I had with:  $ dpkg -l linux-image-\* | grep ^ii ii  linux-image-2.6.38-13-server  2.6.38-13.52  Linux kernel image for version 2.6.38 on x86_64 ii  linux-image-3.0.0-13-server   3.0.0-13.22   Linux kernel image for version 3.0.0  on x86_64 ii  linux-image-3.0.0-14-server   3.0.0-14.23   Linux kernel image for version 3.0.0  on x86_64 ii  linux-image-3.0.0-15-server   3.0.0-15.26   Linux kernel image for version 3.0.0  on x86_64 ii  linux-image-3.0.0-16-server   3.0.0-16.29   Linux kernel image for version 3.0.0  on x86_64 ii  linux-image-3.0.0-17-server   3.0.0-17.30   Linux kernel image for version 3.0.0  on x86_64 ii  linux-image-3.2.0-24-generic  3.2.0-24.39   Linux kernel image for version 3.2.0  on 64 bit x86 SMP ii  linux-image-3.2.0-25-generic  3.2.0-25.40   Linux kernel image for version 3.2.0  on 64 bit x86 SMP ii  linux-image-3.2.0-26-generic  3.2.0-26.41   Linux kernel image for version 3.2.0  on 64 bit x86 SMP   When I try to remove the oldest with this:  $ sudo apt-get purge linux-image-2.6.38-13-server Reading package lists... Done Building dependency tree Reading state information... Done You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies: linux-image-server : Depends: linux-image-3.2.0-27-generic but it is not going to be     installed E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).   How can I free up or extend boot without messing up my installation?


Before the recent changes to the top bar, I'm pretty sure that review queues were always listed in descending order of items pending.  Now we have a drop-down preview on the review icon (thanks!), and I can't figure out what determines the order.  It's not number of items pending (either ascending or descending).  It's not a fixed order of queues.  And it's not necessarily the same order as on the review page when you click through to it.  Examples follow.  This is not a duplicate of .  The SO and network top bars aren't the same, and neither of the explanations on that question, including one from Shog9, is consistent with what I am seeing now.  If Shog's explanation is correct then Close and Reopen should be first on Writers (they're not) and not first on Mi Yodeya (they are).  I don't have enough reputation on SO to check whether what that question reports is still true there.      This is what I currently see on Writers, where I am a moderator.  The sizes of the queues, in order, are: 0, 0, 2, 0, 3, 1.    But it's not a fixed order of queues either.  This is what I see on Mi Yodeya, where I am also a moderator.    And it doesn't match the order on the reviews page:    The reviews page is in descending order, as usual.  I haven't looked at enough cases with the new topbar to know if that's consistent, but I'll assume it is.      This is from Meta.SE, where I am not a moderator, so it's not somehow connected to moderator status.

Currently item order in review page is differ from the equvivalent list from review popup:        In the picture above item order for page view is:   Triage  Documentation  First Posts  Late Answers   For popup menu:   First Posts  Late Answers Triage  Documentation    What's the reason to not make them same? Is it just was overlooked?


In old heritage buildings(50-100yr old). The glass windows (generally coloured) if we tap on the base of the glass and the top of the glass its a completely diff sound. You can clearly make out that the top of the glass is thinner than the base of the glass. So does glass really flow over time ?

I was told by a condensed matter physicist that glass is a liquid with a very high viscosity (it would be more precise to say that it is a ). The example given was that in cathedral windows the glass flows very, very slowly, so they are thicker at the bottom.  I recently read this  in Scientific American, which contradicts the previous statement.  Are there any serious studies about this aspect of glass? Is it only a problem of definition?


I followed the steps listed here:   And if I hit ctrl + shift + T, zsh opens up, but if I start Tilda, it still uses bash.  BUT, the tricky part: if I sudo su on Tilda, zsh appears!  What is happening?

When you drop to the terminal via Applications -> Terminal or Ctrl+Alt+F1 etc. bash is used by default to interpret your commands. If you wish to use another command interpreter (like zsh or fish), how do you get this to start as default?


I want to install Ubuntu 13.10 in my VirtualBox.  When I try it with the 64-bit version, I get this error:  This kernel requires an x86-64 CPU, but only detected an i686 CPU   Ii have an Intel core i5-2430m. as far as I know, it's an 64-bit CPU, and I tried it with the 32-bit version and got this error:  This kernel requires the following features not present on the CPU: PAE   So what should I do now to make it run?  Thank you

I was trying to install Ubuntu 12.04 in VirtualBox 4.2.12r84980. I see    this kernel requires an x86-64 CPU, but only detects an i686 CPU, unable to boot   But I am using a 64 bit Windows 8, and trying same .iso for trying Ubuntu. Then what is the problem?


I want to remove this annoying workspace switch indicator:    I usually use the multiple workspaces to switch quickly and work more efficiently, but this icon doesn't even fade after a few good annoying seconds.

Every time I switch between workspaces in Ubuntu 18.04, I get this thing on the screen (picture below). Is there any way to completely hide it? I want to be able to switch between workspaces instantly without that indicator lingering for a second on my screen.


Which is correct?   "...during the entire hour and twelve minute lecture."   or   "...during the entire hour-and-twelve minute lecture."

Zero hour contract (or zero-hour contract) can be found :                    But more frequent with an s:              or hyphenated:        (to note that this Independent article mixes hyphenated and non hyphenated forms in the same article)  My question is not about zero+plural noun, I am aware of ,  but on the "s" being left when "zero-hour" is used in front of a noun, i.e. as an adjective.   I've noticed that "hours" is sometimes (but rarely though) used, in for instance, "" or "" but "eight-hour day" and "eight-hour shift" seem to be more frequent.   The only explanation I can think of is that an apostrophe ('s) has been lost somewhere in the process and thus should not correct spelling have been either zero-hours' contract or zero-hour contract?  If not why are the usual forms "eight-hour day" (no s) and "zero-hours contract"?


I have windows 8.1 pre-installed in my laptop. But I really didn't like it. Ubuntu is much better. I don't have much knowledge related to how things are done. I want to install Ubuntu in place of windows. But I also want a copy of my windows8.1 so that in future if I ever need I might install windows 8.1 again. I was not provided a windows 8.1 cd with my laptop.

I currently have Windows 7 on my computer and I want to install Ubuntu alongside Windows safely.  Could someone please provide clear instructions?


My understanding of work is that it is the product of a force and the displacement of the object in the direction of the force. So if an object is already moving at 1m/s and we apply a force of 1N in the same direction of motion, is the work done 1J after the object has moved 1m?  This seems wrong to me as it feels like the work done should be less than the case where the object starts with 0 velocity.

Assume a point-mass $m$ is travelling in a straight line, and a force $F$ will act on $m$ (in the same direction as $m$'s velocity) over a constant distance $d$; why doesn't $m$'s velocity matter to the calculation of work done on $m$ by $F$? Work is defined such that, in this example, the work done by $F$ on $m$ is equal to $Fd$, but it seems that if $m$ were moving slower, it would spend more time in the field, allowing $F$ more time to act on $m$, thereby doing more work. In fact, if $m$'s velocity were very great, it would hardly spend time in $F$'s field at all (so very little work done). Maybe I misunderstand work; can someone address this confusion of mine?


Can you advise over it..this was question for me to check but was not able to get this ...if the group can help.. can you advise.. my question is clear that we should not be root or root user to do that

There's an executable that's usually run by user A and writers in a directory only readable, writable, etc. by user A.  Is it possible to allow user B in the same group to run the executable as user A so that it writes in the same directories, etc., without user B knowing the password of user A and without having access to root (i.e. cannot use visudo)?


My question is:  Is $a \le b$ true if $a < b$?   For instance: Is $3 \le 4$ a true statement? I think yes, because $a \le b$ is defined as $a < b\vee a = b$ and this should be true, even if $a = b$ is always false, right?  Thank you very much for your help! FunkyPeanut

If I know for two numbers a and b that    $${a < b }$$  Then is it correct to say that    $$ a \leq b $$  I know that the second statement is true as long as the first one is. It seems OK as it is true but from the other side it seems kinda weird (to me), to say that, if you know, that a is strictly less that b.It's like you lose some extra information.


I would like to change the color (bg and fg) of the remark environment in a Beamer document. I have setup my document using:  \usetheme{AnnArbor} \usecolortheme{crane}   I read in some other question that I should use something like:  \setbeamercolor{theorem text}{fg=black}   or something like  \setbeamercolor{block title example}{bg=orange,fg=white}   I have tried both, using remark or rem instead of theorem or example to no avail. I have to make it clear that I don't want to create a new environment, as I use Lyx and I need to stick to the default "remark" environment, only modified through the preamble.  UPDATE  I have checked that Lyx adds the following definitions to the preamble:  \theoremstyle{definition}      \newtheorem*{defn*}{\protect\definitionname}   \theoremstyle{remark}   \newtheorem*{rem*}{\protect\remarkname}   \theoremstyle{definition}   \newtheorem*{example*}{\protect\examplename}   \theoremstyle{plain}   \newtheorem*{fact*}{\protect\factname}   \theoremstyle{definition}   \newtheorem*{problem*}{\protect\problemname}   \theoremstyle{definition}   \newtheorem*{xca*}{\protect\exercisename}   Is this a Lyx related question instead of a Beamer one?

Hello I'm writing a beamer presentation and I would like to change the colour of the text in the theorem block from one place and it will affect my whole presentation.  Is this possible?  My example:  \documentclass{beamer}   \usetheme{Madrid}   \usecolortheme[RGB={201,20,35}]{structure}   \setbeamercolor{background canvas}{bg=black}  \setbeamercolor{normal text}{fg=white}   \setbeamercolor{theorem text}{fg=black}    %\useoutertheme{shadow}  \useinnertheme{rounded}   \usepackage[utf8]{inputenc}  \usepackage{default}   \begin{document}   \begin{frame}{Primul Slide}   Bla bla bla    Bla bla bla   \begin{theorem}  This is a theorem it is very important!!  \end{theorem}   \end{frame}   \end{document}


I need to add the family font Droid Arabic Kufi Fonts from  into Dspace main css file. Thanks

Is there a way to add some custom font on a website without using images,  or some other graphics?  For example, I was working on a wedding website, and I found a lot of nice fonts for that subject. But I can't find the right way to add that font on the server. And how do I include that font with CSS into the HTML? Is this possible to do without graphics?


So I am in this minecraft world and I was messing around with a command block right next to my build and accidently /tp myself to a random location and it was a repeating block so I am stuck, HELP!

I set a command block to /tp. It was supposed to activate only if you had 0 time left, and to activate the command block with a hopper clock to keep giving it power.   But it is not checking if you have 0 time left, so it keeps teleporting me. I can't get close enough to the command block to break it, so I'm stuck in a neverending teleport loop.  Any ideas?


I just installed Ubuntu for the first time after years of windows usage. In my windows setup I used to have my graphics card powering my main screen and the iGPU power the secondary one. I don't have the slightest idea about getting the same setup in Ubuntu since it won't recognize my second screen. How do I get a second screen powered by iGPU?   Here's a picture of how everything looks after I finished nvidia driver installation

I'm trying to get Intel and Nvidia graphics card working together with two monitors. One monitor should use the Intel card and the other the Nvidia card. Of course, I want to use only one keyboard and one mouse to switch between both screens. Bumblebee didn't work for me.  I don't want to use the xserver-xorg-video-all package because I need the Nvidia card for gaming and I can't use only one graphics card because I need one for KVM virtualisation and the other one for my Linux desktop  So I tried to install the drivers and to configure the Xserver manually. The Nvidia driver is working and I get a video output. But I don't get a video output with the Intel card.  I followed   The config files:


The button is defined in the mainUI thread Here is the part of my code causing trouble-          button.setOnClickListener(new OnClickListener() {         public void onClick(View v){             new Thread(new Runnable() {                  public void run() {                     try {                         OutputStream outToServer = client.getOutputStream();                         DataOutputStream out = new DataOutputStream(outToServer);                         out.writeUTF("Hello from " + client.getLocalSocketAddress());                         final String msg = edi.getText().toString();                         out.writeUTF("Client: " + msg);                          runOnUiThread(new Runnable() {                             @Override                             public void run() {                                 tex.append(msg);                                 if (msg == "quit") {                                     button.setClickable(false);                                     tex.append("quitbutton");                                 }                                 tex.append("Client: " + msg + "\n");                                 edi.setText("");                             }                         });                      } catch (Exception e) {                         e.printStackTrace();                     }                 }}).start();         }     });   Rest of the code here is working perfectly fine. When I send in "quit" as string, the msg variable has it correctly. Problem seems not to be entering the if block at all, because if it did, it should have shown "quibutton" text in the textview, which it ain't.  I'd appreciate any kind of help, thanks :)  Edit- I didn't realize that I wasn't comparing the strings in the right way, not that I don't know how to. It probably got mixed up with C++ operator overloaded function in my head that I wanted to compare strings using == directly.

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


Just wondering if i need to check correlation between categorical and numeric independent variable in R, is there any specific package available in R. Or should i just find the correlation between the numerical independent variable?

I have a nominal variable (different topics of conversation, coded as topic0=0 etc) and a number of scale variables (DV) such as the length of a conversation.   How can I derive correlations between the nominal and scale variables?


i would like to get 847F56B42427DCCD3CB311F905BBEF2097F3AA5F  from "ImageURL": "http://cloud-3.steamusercontent.com/ugc/929312733724516985/847F56B42427DCCD3CB311F905BBEF2097F3AA5F/",  i allready found the regex for this (?<=\/ugc\/.*?\/)(.*.)(?=(\/"))  But Java doesn't accept the "*" in the lookbehind and i struggle to find another solution. The url is always the same, only the numbers after ".../ugc/" are changing.

I have several strings in the rough form:  [some text] [some number] [some more text]   I want to extract the text in [some number] using the Java Regex classes.  I know roughly what regular expression I want to use (though all suggestions are welcome). What I'm really interested in are the Java calls to take the regex string and use it on the source data to produce the value of [some number].  EDIT: I should add that I'm only interested in a single [some number] (basically, the first instance). The source strings are short and I'm not going to be looking for multiple occurrences of [some number].


The computer is relatively old and underpowered, so video playback of high quality videos is jerky with any player.  How do I convert a high quality video to low quality video?  EDIT: I tried avconv -fs to limit size and -filter scale=iw/2:ih/2 to resize to 1/2; with output to mp4 and mpg. All 4 resulting files are not very good: vlc can play the video, but the quality is abysmal on the 1366x768 screen. The source format is Video: h264 (High), yuv420p, 1920x800, 2030 kb/s, 23.98 fps, 23.98 tbr, 24k tbn, 47.95 tbc, bitrate: 2127 kb/s (as reported by avconv).

I need a good video converter application that can convert from/to many video formats. On Windows I found  to be good. I would like its equivalent or something better on Ubuntu.


Say you wanted to find the period of $x(t)=\sin(at)\sin(bt)$ where $a$ and $b$ are real constants. How could you go about this?

Suppose that period of $f(x)=T$ and period of  $g(x)=S$, I am interested  what is  a period of $f(x) g(x)$? period of $f(x)+g(x)$? What I have tried is to search in internet, and found following  for this.  Also I know that period of $\sin(x)$ is  $2\pi$, but what about $\sin^2(x)$? Does it have period again $\pi n$, or? example is following function $y=\frac{\sin^2(x)}{\cos(x)}$ i can do following thing, namely  we know  that  $\sin(x)/\cos(x)=\tan(x)$ and period of tangent function is $\pi$, so I can represent $y=\sin^2(x)/\cos(x)$ as $y=\tan(x)\times\sin(x)$,but how can calculate period of this?   Please help me.


This is the only mammal that can fly.   We were taught that an independent clause must have a complete thought/idea. How can "This is the only mammal" be treated as an independent clause?

We were taught that an independent clause must have a complete thought/idea.     This is the only mammal that can fly.     How can "This is the only mammal" be treated as an independent clause?            It was a grammar lesson and there was no context there. In this situation how can I decide that it is an independent clause? Though for sure, there should be an independent clause in a correct sentence, and the clause starting with 'that' is not independent. But by this way, I can't fit it with the rule that every independent clause must have a complete thought. A simple sentence must have an independent clause. If the sentence has no independent clause how we can call it a sentence? Can even two dependent clauses form a sentence?


I need to compare two files with same tags, but they have some different values and I need to print three lists:  Set<Costo> list1 = read.getCostos("path1");         Set<Costo> list2 = read.getCostos("path2");          Set<Costo> list3 = ListaCostoUtil.listaConjunta(list1, list2);         Set<Costo> plus = ListaCostoUtil.listaComplementoMenos(list3, list2);         Set<Costo> minus = ListaCostoUtil.listaComplementoMas(list3, list2);   where list1 is my first XML file and list2 is the other, I need to print a list3 where is a complete list of all the elements from list1 and list2.  With list plus I just need to compare my list3 with list2 and throw all the elements that are not on list2 with a "+" and it's the same with minus but just adding a "-", how could I start doing it? thanks

I'm trying to write an automated test of an application that basically translates a custom message format into an XML message and sends it out the other end.  I've got a good set of input/output message pairs so all I need to do is send the input messages in and listen for the XML message to come out the other end.  When it comes time to compare the actual output to the expected output I'm running into some problems.  My first thought was just to do string comparisons on the expected and actual messages.  This doens't work very well because the example data we have isn't always formatted consistently and there are often times different aliases used for the XML namespace (and sometimes namespaces aren't used at all.)  I know I can parse both strings and then walk through each element and compare them myself and this wouldn't be too difficult to do, but I get the feeling there's a better way or a library I could leverage.   So, boiled down, the question is:  Given two Java Strings which both contain valid XML how would you go about determining if they are semantically equivalent?  Bonus points if you have a way to determine what the differences are.


I just noticed , the GoDaddy-SOPA one.  On thing that confused even me, as a 6k user on Meta, was this:    Now, I knew after a second's thought that the question was closed and no new answers were being accepted. However, that protection threw me off. Specifically the last line:      To answer it, you must have earned at least 10 reputation on this site.   So... If I have 10 rep I can answer it?  No, but that's what it says.  The whole point of a protection is to keep answers from new users clogging up the question. If the question is closed, it doesn't need the protection, right? If it is later reopened, the protection should come back.  Therefore, I propose that we simply hide the protection indicator when a question is closed,** to reduce a small amount of confusion.

If the question is locked, obviously new users can't post answers to it because no one can post answers. It seems somewhat redundant to list that box there. I'm not saying remove the protection from the question just because it's locked. After all, a question can be unlocked (although unlikely). However, it is unlikely and it's just an extra box there that doesn't really mean anything on the post anymore.  Most notably for the "protected" box, it states:     To answer it, you must have earned at least 10 reputation on this site.   Yet, because it's locked, that statement is untrue.    The "protected" box should be hidden when it is not possible to add additional answers to the question in the first place, which includes when the question is locked or closed. If the question is unlocked or reopened, it should be shown again.


Show that if the optimal value of the objective function of a linear programming problem is attained at several extreme points, then it is also attained at any convex combination of these extreme points.     Definition. convex combination  A point $x\in\mathbb{R}^n$ is a convex combination of the points $x_1,x_2\dots x_r$ in $\mathbb{R}^n$ if for some real number $c_1,c_2,\dots,c^r$ which satisfy$$\sum_{i=1}^rc_i=1\text{ and }c_i\ge0,\space1\le i\le r$$have$$x=\sum_{i=1}^rc_ix_i$$    Proof.  let $f:\mathbb{R}^m\to\mathbb{R}$ be the objective function, $M$ be the optimal value, $c_1,\dots,c_n\ge0$ and $\sum_{i=1}^nc_i=1$  Assume $x_1,\dots,x_n$ are optimized solutions which are on the extreme points  $$f(x_1),\dots,f(x_n)=M$$  Show any convex combination of $x_1,\dots,x_n,s.t.$  $$x=c_1x_1+\dots+c_nx_n$$ is also a optimized solution$$\text{WTS } f(c_1x_1+\dots+c_nx_n)=M$$  Since $f$ is linear, have the following:  $$f(c_1x_1+\dots+c_nx_n)=c_1f(x_1)+\dots+c_nf(x_n)$$  $$=c_1M+\dots+c_nM=(c_1+\dots+c_n)M=M$$  Therefore convex combination of also also has a optimized value  Now show them are all feasible solutions  Since $x_1,\dots x_n$ are feasible we have  $$Ax_1,\dots,Ax_n\le b\wedge x_1,\dots,x_n\ge0$$  $$\text{WTS }A(c_1x_1+\dots+c_nx_n)\le b\wedge c_1x_1+\dots c_nx_n\ge0$$  Since $Ax_1,\dots,Ax_n\le b$ that   $$c_1Ax_1\le c_1b\wedge\dots\wedge c_nAx_n\le c_nb$$  $$\Rightarrow c_1Ax_1+\dots+c_nAx_n\le b(c_1+\dots+c_n)$$  Since A is a linear transformation, have the following:  $$\boxed{A(c_1x_1+\dots+c_nx_n)\le b}$$  Second part that $$\boxed{c_1x_1+\dots+c_nx_n\ge0}\text{ is trivial}$$  This proves any convex combination of these extreme points are optimized feasible solution.$\tag*{$\square$}$  Is my proof correct, any suggestions$?$

The question asks me to "show that if the optimal value of the objective function of a linear programming problem is attained at several extreme points, then it is also attained at any convex combination of these extreme points."  I try to write a convex combination of all extreme points $$f=c_1x_1+…+c_nx_n.$$  However, a theorem of extreme point is that "not a convex combination of other points". This makes me confused. If a convex combination can not be an extreme point then how can I get the optimal value of the objective function？


Does an Indian citizen with valid passport and with expired US visa travel from USA to India via Munich without any transit visa?

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


When I tried to bold-face words spanning comma for English grammar questions that whether or not comma should be used, e.g. "unified**, will** induce the risks of strangling the usage of ...", that comma and following words put inside pair of double asterisks won't bold-faced in preview. I may not understand the correct way to do that or it's just how things are designed this way? I ended up moving the opening double asterisks in front of the word before the comma I wanted to highlight.

Possible Duplicate:          This is a simple bug: You can't make individual letters in a word bold.  Example:  **SVG** stands for **S**calable **V**ector **G**raphics      SVG stands for Scalable Vector Graphics   Dirty(?) Workaround:  I found a workaround that uses the Unicode character "Zero-Width Joiner" to separate the letters from the rest of the word code-wise, but not visually.  **SVG** stands for **S**&zwj;calable **V**&zwj;ector **G**&zwj;raphics      SVG stands for Scalable Vector Graphics


Is the following statement true: Gradient descent is guaranteed to always decrease a loss function.  I know that if the loss function is convex, then each iteration of gradient descent will result in a smaller loss, but does this statement hold for all loss functions? Could we design a loss function in such a way that performing gradient descent was not optimal?

In  it says     To make gradient descent work correctly, we need to choose the learning rate η to be small enough that Equation (9) is a good approximation. If we don't, we might end up with $\Delta C>0$, which obviously would not be good! At the same time, we don't want $\eta$ to be too small, since that will make the changes $\Delta v$ tiny, and thus the gradient descent algorithm will work very slowly. In practical implementations, $\eta$ is often varied so that Equation (9) remains a good approximation, but the algorithm isn't too slow. We'll see later how this works.   But just a few paragraphs before we established that $\Delta C\approx−\eta\nabla C⋅\nabla C=−\eta\|\nabla C\|^2$ is obviously always negative (for positive $\eta$). So how can $\Delta C$ be positive if we don't choose a small enough learning rate? What is meant there?


I use following code:

    and get    I hope align green part to center, how to do it?

How can I horizontally center a
 within another
 using CSS?

Foo foo


I am running 13.10, when I try to wake my computer from suspend the screen doesn't seem to activate. Any pointers as to where I am going wrong? I just have to manually reboot the computer for it to come to life again!

I'm using Ubuntu 12.04 & everything about it is great except that it just won't resume after suspend. I've tried the suggestions listed in this thread  but none worked. I'm using Lenovo Y510P. I'm new to Ubuntu, or unix for that matter, so please let me know if there's anymore  information that I should be posting. Thanks.  update  I tried the suggestion by Dima on this post . The machine wakes up from hibernation but immediately the screen gives a screen like this     Wondering if this is an issue with the graphics card or something.


I just noticed that my profile on Programmers no longer shows my flag weight. Instead I see the number of helpful flags. At the same time, the definition for the Marshal badge has been changed to "500 helpful flags".  Does that mean there is no more flag weight? All that counts now is the number of helpful flags? Doesn't this also mean that there is no more penalty for declined flags?

Update , but there appears to be no documentation out there. The change in flag weight caused by each flagging still missing. TL;DR: Flag weight is not very clear. Just telling the user how many flags got approved/rejected would increase the flagging behavior. Additionally, flag feedback could improve this even more. Question:  is shown on a User's profile as a number between 0 and 750, each user starts with 100. The problem is that after reaching 500, flag weight increases in a sub-linear fashion, and it becomes hard to tell how many flags were considered to be correct or incorrect. I find it easy to remember "I am at 250" and when I come back, discover "I am at 280", so I had 3 flags approved. Nowadays, "I am at 576.3529". When I view my profile tomorrow, I'll be at 577.1285 or something, but I won't know how many flags got approved, denied or were ignored.  Would "10 flags approved, 3 flags denied, 2 flags pending" not provide more useful information? Even if it's just a pop-up box (StackExchange seems to use span-title for that). Additionally, being able to see what flags were denied would provide feedback to the user that is flagging in a way not desired by the moderator(s), and improve the flagging quality.  Maybe we can click on the flag weight to see a page with all our flags, the status (approved/denied/pending), the moderator that reviewed the flag, and maybe a comment the moderator left to explain why the flag was denied?


Given positive integers $n, r$, with $p$ a prime, and $n^2/r^2 = p$, prove that $n$ is divisible by $p$.  Use proof by contradiction (I am sure there are easier ways to prove this, but this is what the book requests, since the chapter is exercises on proof by contradiction). I started off by assuming that $n$ is not divisible by $p$, therefore: $n = ap + b$ for a non-negative integer $a$ and a positive integer $b$. $n^2 = pr^2$, so $(ap+b)^2 = pr^2$ I expanded this out to get a quadratic polynomial in $b$: $b^2 + 2apb + a^2p^2-r^2p = 0$ Using the quadratic formula, I found: $b = -ap \pm r\sqrt{p}$ Since $a$, $r$, and $p$ are integers, and $p$ is prime, then both of these values of $b$ would therefore be irrational, violating the condition that $b$ must be a positive integer. I'm not sure if this proof works or not.  It doesn't feel very elegant (compared to some of the examples in the book).  Could you please critique it?

I want a proof of Euclid's theorem (if p is prime and p|(a.b) where a and b are integers, then either p|a or p|b) using the fundamental theorem of arithmetic.  I already understand the proof assuming p is not |a and using gcd(p,a). I want a proof that rely's on FTofA.  Searching on line I can find examples of using Euclid's lemma to prove Fundamental Theorem of Arithmetic but I want to go the other direction, and assuming Fundamental Theorem of Arithmetic, prove Euclid's lemma.


I'm trying to understand the java compiler generics types erasure with the following exemple. Can someone explain me why can i add a new motor bike into a list of Car ?   List<Vehicle> list = (List<Vehicle>)(Object)new ArrayList<Car>();  list.add(new MotorBike());

I read about Java's type erasure .  When does type erasure occur? At compile time or runtime? When the class is loaded? When the class is instantiated?  A lot of sites (including the official tutorial mentioned above) say type erasure occurs at compile time. If the type information is completely removed at compile time, how does the JDK check type compatibility when a method using generics is invoked with no type information or wrong type information?  Consider the following example: Say class A has a method, empty(Box<? extends Number> b). We compile A.java and get the class file A.class.  public class A {     public static void empty(Box<? extends Number> b) {} }     public class Box<T> {}   Now we create another class B which invokes the method empty with a non-parameterized argument (raw type): empty(new Box()). If we compile B.java with A.class in the classpath, javac is smart enough to raise a warning. So A.class has some type information stored in it.  public class B {     public static void invoke() {         // java: unchecked method invocation:         //  method empty in class A is applied to given types         //  required: Box<? extends java.lang.Number>         //  found:    Box         // java: unchecked conversion         //  required: Box<? extends java.lang.Number>         //  found:    Box         A.empty(new Box());     } }   My guess would be that type erasure occurs when the class is loaded, but it is just a guess. So when does it happen?


I have the following string, from which I want to extract the value of the key2 which is value2  [key1=value1,key2=value2,key3=value3]   I tried giving the following regex ,key2=(.*),\w+but it is extracting ,key2=value2,key3but I am want only the value value2  What regex can be used for this one?

I have this gigantic ugly string: J0000000: Transaction A0001401 started on 8/22/2008 9:49:29 AM J0000010: Project name: E:\foo.pf J0000011: Job name: MBiek Direct Mail Test J0000020: Document 1 - Completed successfully  I'm trying to extract pieces from it using regex. In this case, I want to grab everything after Project Name up to the part where it says J0000011: (the 11 is going to be a different number every time). Here's the regex I've been playing with: Project name:\s+(.*)\s+J[0-9]{7}:  The problem is that it doesn't stop until it hits the J0000020: at the end. How do I make the regex stop at the first occurrence of J[0-9]{7}?


I will be flying from Halifax to Calgary (for any non-Canadians, its about 4500km, 5 hour flight) a couple weeks from now, and need to bring my new iMac with me.  The reason I say 'new' iMac is because the current model is smaller and lighter than previous ones.  The official size and weight from the Apple site are:     Height: 17.7 inches (45.0 cm)      Width: 20.8 inches (52.8 cm)      Stand depth: 6.9 inches (17.5 cm)      Weight: 12.5 pounds (5.68 kg)   I am hoping that I will be able to take it as carry on, because I really don't want to check it with the rest of the luggage.  My question is:  does anyone have experience taking their iMac with them on a plane?  If so, could you take it as carry-on?    Here are the specs:   Note that this is different to the existing question on , because an iMac is a different shape and has an integrated screen.

I am moving from Egypt to the Netherlands and I need to take my PC with me. I won't be taking the monitor, just the case, but I'm wondering what the best way would be.  Am considering taking it as carry-on because I'm allowed 8kg and at least then I can handle it myself. Has anyone done this before and can give me tips or warn me that this doesn't work? Would putting it in my normal suitcase as checked baggage be a better idea?


I have been writing functions like   var functionname = function(param) { }   rather then   functionname(param) { }   does it provide any advantage of the format or any garbage collection happens when i write like the first syntax?

I've recently started maintaining someone else's JavaScript code. I'm fixing bugs, adding features and also trying to tidy up the code and make it more consistent.  The previous developer used two ways of declaring functions and I can't work out if there is a reason behind it or not.  The two ways are:  var functionOne = function() {     // Some code };     function functionTwo() {     // Some code }   What are the reasons for using these two different methods and what are the pros and cons of each? Is there anything that can be done with one method that can't be done with the other?


I was making a scene in blender and I wanted to change the texture from "Material_1" to "Material_2". It lets me change it but when I go to rendered view the part looks the same. can someone please help me

How do you add more than one material to a mesh?   I have tried adding two materials to the object, and then assigning one of the materials to a vertex-group, but I could not find a place to assign it.  I am making a striped bouncy ball that I want to deform, so adding a different material by separating the mesh into different objects would not be ideal.


I have a simple python module as follows: from kafka import KafkaConsumer  consumer = KafkaConsumer(     'myTestTopic',     bootstrap_servers=['localhost:9092'],     auto_offset_reset='earliest',     enable_auto_commit=True)  for message in consumer:     message = message.value     print(message)  This will return something like follows:  b'&name=bob&gender=M&type=student&sId=1204&note=temp&' b'&name=bob&gender=M&type=student&sId=1204&'  My question is: Is there a neat way to remove/trim the first two characters e.g: (b') and the last character (') from each line that will be returned? So essentially it will appear like:  &name=bob&gender=M&type=student&sId=1204&note=temp& &name=bob&gender=M&type=student&sId=1204&

I'm using this code to get standard output from an external program:  >>> from subprocess import * >>> command_stdout = Popen(['ls', '-l'], stdout=PIPE).communicate()[0]   The communicate() method returns an array of bytes:  >>> command_stdout b'total 0\n-rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file1\n-rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file2\n'   However, I'd like to work with the output as a normal Python string. So that I could print it like this:  >>> print(command_stdout) -rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file1 -rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file2   I thought that's what the  method is for, but when I tried it, I got the same byte array again:  >>> binascii.b2a_qp(command_stdout) b'total 0\n-rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file1\n-rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file2\n'   How do I convert the bytes value back to string? I mean, using the "batteries" instead of doing it manually. And I'd like it to be OK with Python 3.


Let $m, n \in N$ and $a, b \in Z$ so that $ m\mid n$ and $a \equiv b \mod n.$ Then $a \equiv b \mod m$

I noticed relation between modulo operation and number which is power of two  Example I have to calculate $ 3431242341 \mod 2^5 $, which is $ 5 $ but it is equivalent to  $ ( 3431242341 \mod 2^9 ) \mod 2^5 $   I tried many examples and it seems to be true in general, and I am not sure if it is a coincidence or true in general that I can use first modulo operation ( greater number) and the result will be the same.


I have a project where I want to get numbers only as input so I'm using a input of type number but this also allows decimal seperators etc. how would I prevent the use of , . and e.  I have looked around and couldn't find one that gave the desired result, sinds they either didn't block the decimal inputs, or would allow a user to still paste it in the field.  I have javascript and jquery that I can use, but I do not want to use an external librairy.  If anyone would be able to help me that would be appriciated.  function LimitKeys($id) {             $field = document.getElementById($id);     $value = $($field).val(); //if the value contains multiple e , or . the value is no longer valid and gives me blank     console.log($value);     $regex = /[^\d]/;      $val = $value.replace($regex, "");// cant replace in blank     console.log($val);     //$($field).val($val); }  $('.number-only').keypress(function (event) { //sinds it's on keypress it won't catch the paste of data.     console.log(this.value);     var regex = new RegExp("^[0-9]+$");     var key = String.fromCharCode(!event.charCode ? event.which : event.charCode);     if (!regex.test(key)) {         event.preventDefault();         return false;     } });

Is there a quick way to set an HTML text input (<input type=text />) to only allow numeric keystrokes (plus '.')?


Let $A$ be the set of all functions $f:\mathbb R\to\mathbb R$ that satify the following two properties:  $f$ has derivatives of all orders, and  for all $x,y \in \mathbb R$, $f(x+y)-f(y-x)=2xf'(y)$   Show that any $f \in A$ is a polynomial of degree $\le 2$. One proof is very easy. Any polynomial of degree $\le 2$ belongs to $A$ is easy to prove. Please help me with the proof of the converse : No other functions belong to $A$.

Let $A$ be the set of all functions $f:\mathbb{R}\to\mathbb{R}$ that satisfy the following two properties:  (1) $f$ has derivative of all orders, and  (2) for all $x,y \in \mathbb{R}$, $f(x+y)-f(y-x)=2xf'(y)$.  Which of the following sentences is true?  (a) Any $f\in A$ is a polynomial of degree less than or equal to 1  (b) Any $f \in A$ is a polynomial of degree less than or equal to 2  (c) $\exists f \in A$ which is not polynomial  (d) $\exists f \in A$ which is a polynomial of degree 4  It is a problem from TIFR GS-2018. I have found polynomials upto degree 2 hold this properties but have to exclude the possibility of (c) and (d). I also found out if $f'(x)$ has at most one real root and clearly graph of $f$ is symetric about that root. How can I proceed further?


I am confused...  People usually say that "DNA" is made of two strands deoxyribonucleic acid bound together. Nonetheless, the acronym "DNA" means "deoxyribonucleic acid".   So by logic, a molecule of "DNA" should be only made of one strand of deoxyribonucleic acid, and not two! Right?  This is really confusing...

Our molecular biology teacher told us that a double helix of DNA was composed of two DNA molecules linked together by hydrogen bonds. The thing is, until now, I always thought a DNA molecule was composed of two strands, those being polynucleotides, both of them being linked together. I can't find a link which is saying the same as my teacher, even if it seems technically correct to call a double helix a dimer of two DNA molecules.  I was curious to know what was the exact terminology.


#include<stdio.h> void main() { char ch; ch=getchar(); printf("%d",ch); }   This gives me error NZEC (non zero exit code) but when I use-  #include<stdio.h> void main() { char ch; scanf("%c",&ch); printf("%d",ch); }   No execution error and accepts solution What's wrong with getchar() ?  I am quite new to C so don't know much I checked few answers on difference between scanf and getchar but I could not understand. Please help me in understanding this behaviour.  Solution: I did not know that my query is related to this question:   Moreover both of these are working-  #include<stdio.h> void main() { int ch; ch=getchar(); printf("%d",ch); }   changing char to int and-  #include<stdio.h> int main(void) { char ch; ch=getchar(); printf("%d",ch); return 0; }   changing void to int

What is the correct (most efficient) way to define the main() function in C and C++ — int main() or void main() — and why? And how about the arguments? If int main() then return 1 or return 0?  There are numerous duplicates of this question, including:       — For C++, with a very good answer indeed.     Related:


I remember from my basic physics class 3 years ago that (every?) object naturally emits EM radiation. I also remember that temperature is directly proportional to the frequency of the EM waves. Does it then follow that any object with a low enough temperature emits waves with a very low frequency, such as radio waves? If so, are these emissions detectable with current instruments?

I already know the fact that when solid objects heat up, they emit thermal energy which is also known as infrared radiation.  However, if the atoms in that solid were to begin gaining more or less kinetic energy, could the excited electrons then begin emitting radio wave or gamma wave radiation in the far regions of the electromagnetic spectrum?