Since I earned the privilege to downvote I used it when ever I saw a post of low quality and used this feature intuitively.  But when I asked myself today what exactly are downvotes meant for? Are they meant for incorrect content? Just for low quality? Or even for posts that are not helpful?   I went looking in the Stack Overflow helpcenter and noticed that there wasn't any information about it (expecting the little hint when you hover with your cursor over the downvote button). So maybe thats a good idea to add to avoid unintended abuse of downvotes?   Lets collect here some cases, what downvotes are meant to be used for and what not.

I have seen a few  here on Meta Stack Exchange that cover parts of this, but they are often too local, and none of them seem to cover all the relevant scenarios.  I will break it up into multiple parts in order to make this more specific:     When should I vote on a question:   What are the qualifications for a question to be deserving of being up-voted? When shouldn't I vote up on a question? What are the things that would cause a question to need to be down-voted?   How should I go about down-voting the question (do I wait a little while to give the OP a chance to change it, or do I down-vote it immediately)?  When shouldn't I vote down on a question?  When should I vote on an answer:   What are the qualifications for an answer to be deserving of being up-voted? When shouldn't I vote up on an answer? What are the thing that would cause an answer to need to be down-voted?   How should I go about down-voting the answer (do I wait a little while to give the OP a chance to change it, or do I down-vote it immediately)?  When shouldn't I vote down on an answer?  When should I vote on a comment:   While votes on comments do not affect reputation points, it might be useful to new users to know when to up-vote them.    It seems that a full, comprehensive list of these would be invaluable to new users looking to figure out how the voting system works, but this list seems to be missing from the meta site.


How many ways are there to arrange the letters in INTELLIGENT with at least two consecutive pairs of identical letters?  I know that we would use the inclusion exclusion principle here and that there are $\dfrac{11!}{2!2!2!2!2!1!}$ ways to arrange the word with no restrictions.   My first guess would be to assign two pairs of identical letters as a single block which we could choose two pairs from five possible pairs to get the pairs themselves. Then these pairs could be arranged in such a block in two ways. Then we would have to figure the number of ways to arrange this block in the entire word. I'm just confused where to go from here...

How many ways are there to arrange the letters in INTELLIGENT with at least two consecutive pairs of identical letters?  I got an answer of  $$C(5,2)\cdot\frac{9!}{2!^3}-C(5,3)\cdot\frac{8!}{2!^2}+C(5,4)\cdot\frac{7!}{2!}-6!\;,$$  but the solution manual says   $$C(5,2)\cdot\frac{9!}{2!^3}-2\cdot C(5,3)\cdot\frac{8!}{2!^2}+3\cdot C(5,4)\cdot\frac{7!}{2!}-4\cdot 6!\;.$$  Where am I going wrong? can someone explain where the $2\cdot,3\cdot$, and $4\cdot$ are coming from in the solution manual?


I have two columns [first name] [last name]  I need to merge them to one column to see [first name last name]

I need to combine multiple columns into a single column, so:  one     four    seven two     five    eight three   six     nine   Becomes:  one two three four five six seven eight nine


Let $f$ be Lebesgue integrable on $\mathbb{R}$. Show that  $ \sum_{n=1}^{\infty} f(x+n) $ converges almost everywhere.   I was thinking that maybe the finite sum could be compared to a simple function and maybe this could lead somewhere, but i've doubt this since I don't know what the level sets look like for the $f(i)'s$. The result seems a  bit obvious but I don't have a good idea.  Any helpful hints or help would be great

Assume $f:\mathbb R\rightarrow  {\mathbb R} $ is Lebesgue integrable, prove $\sum_{n\in\mathbb N } f(x+n)$ converges for almost everywhere x. This is a question discussed with friends. Thanks


Simply put, will continuously simmering vegetables for days, even up to a week or two, in a perpetual stock lead to unexpected or unwanted results? Since even the longest stock recipes I know don't take more than a day to make, I assume flavour extraction will stop after a few hours but does cooking veggies beyond that point generate off-flavours? I've also looked up safety concerns of perpetual broths; in this case, since it's a vegetarian one consistently kept at a simmer to which I will regularly add boiling water, I don't think it will be an issue. I'm still new to food-science though so I might have missed something there. Some answers, for example  by  or  by , partly answer this question, however, I don't think it's specific enough to render this one a duplicate.

I'm making veal stock that's later going to be reduced to a glace viande.   In the past, I was always close enough to observe the process and strain the stock . I also realize that an hour or two and even longer isn't an issue when making stock.  But today I will be away for most of the day and my stock pot will remain unattended on the lowest possible heat on the stove. I don't expect any problems from this procedure. But it prompted a question:  How long could a pot of bone stock be simmered? Is there an upper threshold when unwanted substances are extracted from the bones? When the flavour profile does not get "better" but starts to deteriorate?    Clarification:     I am not talking about cooking a day or two, I know that this is typically no problem. And yes, if necessary I could add water to counter evaporation. For this question, you may assume "no time limit". I am familiar with the concept of . But for a perpetual stew, parts of the stock are removed and new ingredients added. I'm asking explicitly about one unchanged stock: a pot of bones in water, optionally some spices and mirepoix.


I've been using Ubuntu or 4 years now, and haven't used windows since, and I need windows to do some important developing things, that Ubuntu can't (well it can but i can not figure it out) So I still need Ubuntu but I also wanna be able to run windows when i need to, with a partition. I know how to use partitions but I don't know how to use another operating system with partitions. So I have the .iso windows thing installed, so all i need to do is run it with a partition. I just dont understand how to use it with the partition. I know it is possible, I've seen it, but I don't know how to do it for myself. Do I need to use UFEI to do so? Or is it just partitions. I've searched and can't find anything that works properly.

I have Ubuntu on my laptop. Now I want install Windows 7 in a dual-boot. How can I do this? I can't lose my Ubuntu files, and I'm afraid that I might break . Go  for UEFI only!


I have submitted my manuscript to one of the peer-reviewed journals of chemistry and the decision was 'recommended for publication subject to minor revision'. I have submitted the revision but two weeks have passed and the status is still showing that the manuscript is in peer review in scholar one. Please suggest future steps. Thank you

I just received a decision letter from a journal editor (after three rounds of major revision). The letter shows that the reviewers "have asked for some other minor revisions". After getting the minor revision letter, I immediately completed the revision in accordance with the feedback from the reviewers (the suggested changes just involve adding a few sentences) and immediately resubmitted the revision to ScholarOne. A week has passed since I submitted the revision, but the status in ScholarOne remains unchanged. Is this normal? Can I assume that this basically means "acceptance with minor revision"? Thanks for your insight and sharing.


If I am following a closed question, can I please be notified when it is reopened? Concrete example:  on CrossValidated. It was originally closed as unclear, but the OP clarified, so I voted to reopen and followed the question, intending to write an answer when it was reopened. However, it turns out that it was reopened, but although I was following it, I did not get a notification. (The OP posted a comment alerting me to the reopening.) I think this kind of use case may be pretty common. Note that .

Does a feature like this exist? A question has been closed, because the user must write it in a better way. I have already an answer for it, and it would be great to have an alert/notification when it will be open again.


What would be the gravitational acceleration at half at Earth's radius? Something tells me it should be proportional to the mass distributed in that part, but I am not sure.  Of course, we assume we know what's the acceleration at Earth's surface. Also, for the sake of it let's assume Earth has uniform density and is a perfect sphere.

Would the effect of gravity on me change if I were to dig a very deep hole and stand in it? If so, how would it change? Am I more likely to be pulled downwards, or pulled towards the edges of the hole? If there would be no change, why not?


I have Windows and Ubuntu installed on the same hard disk (I created two partitions). The problem is that I can get only to the last system I installed. I installed Ubuntu and then Windows and therefore I can get only to my Windows. Is there a way to fix it?

I just installed Ubuntu alongside Windows 7. Now I cant boot Windows 7 because it automaticaly boots Ubuntu without displaying boot menu. How can I get menu with options to choose which Os to boot? Can anyone help?


I am pretty new to latex and have seen a paper which font I would like to use. I think some of the advance users will recognize it in a minute or so. Can someone help me out?  Thanks in advance.  Peter

Is it possible to identify the font used in a specific document/picture?  Answers to this question should identify:   Possible methods to do this (perhaps one answer per method) and adequately describe how to use it (as opposed to merely stating it); Ways of finding the identified fonts, if possible (free or not); and Any prerequisites associated with the method used, if required (for example, "In order to use method X, your document has to be in format Y").   This question is meant as an FAQ, based on an . Its aim is to facilitate the community with the general procedures involved in font identification. Similar cases are solved on a per-usage basis on 's  tag.


I just started my 2nd year of master and it's already time to apply for a PhD in math, deadlines are in ~1+ month.  In most samples, students had a clear idea of what they would like to study. They write that they have studied this and that, and that they would like to be under Prof. X's supervision because they worked on his papers.  As for me, I liked most math topics that I have studied, with very few exceptions. In short, I'm undecided, exactly when I buy an ice cream and  I'm facing 20 good flavours.   Most universities, on their application page, offer "undecided" among the options (algebra, number theory, ...). Although they may say "it's totally fine" (because everything is nowadays), what is the truth behind the appearances?  Stories from people who are on admissions committees or from [un]successful applicants who wrote that in their SOP are most welcome.  EDIT: I successfully got admitted to some really good US universities with "undecided" in my SOP

When applying for the PhD program in mathematics, usually, one is not required to specify in what field (e.g., PDE, dynamical system, etc.) he/she intends to do. However, I don't know whether it will be disadvantage that one does not have a specific field in mind at all.   I ask this question because some people suggest the students who are applying to the graduate school should talk to or connect with the professor who is in the school he/she intend to apply for. But if one does not even have a specific interest in mind, how can he/she talk to a professor about his/her application? (Even if the student is interested in analysis, say, there are lots of sub-field in analysis.)  So, here is my question:  Does one need a very specific field in mind to apply a PhD program in mathematics? Would this be thought as advantage or disadvantage of an application?


I have a list of words (some of them are colors, some of them are not) written in a .txt file.  I need to save these words into an array so that I can apply color to a grid later on. How do I turn this file into an array?

I have a file (called "number.txt") which I want to read to an array in Java. How exactly do I go ahead and do this? It is a straight-forward "1-dimensional" file, containing 100 numbers.  The problem is that I get an exception every time. Apparently it can't find it (I am sure its spelled correctly). When looking through code examples, it doesn't specify the file's entire file path, only the name of the file itself. How would I go about doing that if its necessary?  Also, when reading the file, will the array automatically contain all the lines of the file, or will I have to make a loop which which copies every line to corresponding subscript i?  I've heard of BufferedReader class, what it's purpose, and how does it corelate to reading input?


In an interactive shell session, how do I copy to clipboard text that was cut with Ctrl+U? Without using the mouse, obviously. Thus making it available for other GUI applications, instead of pastable only with Ctrl+Y only in the terminal where the Ctrl+U was issued.  Update: added bash tag to cover answers involving bash-only solutions.

In  the top answer shows how to copy text that has been previously selected with the mouse on a gnome-terminal, to the clipboard in X11.  My question is: Say I copy a piece of text from the terminal using bash set-mark and copy keyboard shortcuts (i.e. set-mark + M-w). Is it possible to share this clipboard with X11?   EDIT: In the original question, I talked about sharing the clipboard with GNOME, but as Gilles points out below, GNOME doesn't specifically have a clipboard (it's general to X), so I have updated the question.


I've been doing a number of panoramas of a flat barren landscapes lately, but I have been running into issues with a wavy horizon.  I can remedy this to a certain degree in Photoshop with cloning but surely there must be a better way to fix the geometry/projection.  I love the convenience of doing panoramas in Lightroom and getting a DNG output to work with afterwards. Is there a way by means of a plugin or otherwise to correct this in Lightroom itself?  If not, please recommend efficient Photoshop methods.

It's the lookout tower below. You can't shoot from a single place - you take pictures from four different positions, distant a few meters one from another.  I know there logically must be problems on nearby trees (distant only tens to hundreds of meters) but I'd accept enblend retouching/blurring here.  What do I need to prevent are bumps on the horizon. There shouldn't be any as it is tens of kilometers away!  Note 1: I hoped I could add control points manually (without help of Hugin's CPFind) - on the horizon only - but the results have still been poor.  Note 2: Taken without a tripod. I assume it's not a problem though as I've taken tens of other panoramas handheld and they've been stitched perfectly in Hugin.


Let: $S_m = \sum_{k=0}^n{((-1)^{n-k}}C_n^kk^m)$. I need to calculate $S_m$ for all $m=0, 1, \ldots, n-1$. As I undertood, it should be equal to zero for all $n, m$ (according to some computations on my PC). But I have no idea how to solve it more formally.

Prove $$\sum_{k = 0}^{n}(-1)^{n - k} \binom{n}{k} \cdot k^n = n! \qquad\text{and}\qquad \sum_{k = 0}^{n}(-1)^{n - k} \binom{n}{k} \cdot k^m = 0,$$ where $m \in \{0, 1, 2, \cdots, n - 1\}$.  To be honest, I tried to use some combinatorial ideas but was not able to see interconnections. Also, I had an idea to prove it using induction but failed to do that either. Help will be much appreciated! I just got stuck and don't see any continuation of solution for this problem


I'm trying to create a nav bar with a search bar within the nav bar. The problem is that the background color behind the unordered list part of the nav bar is just white like the rest of the page. Shouldn't it be the background color I set it to? HTML

 Home

 Home

         <input class="form-control py-2" type="search" placeholder="Search..." id="example-search-input">                      <button class="btn btn-outline-secondary" type="button">                              </button>

   CSS   ul {   list-style-type: none;   margin: 0;   padding: 0;   border: 1px solid #e7e7e7;   background-color: #f3f3f3; }  li {   float: left; }  li a {   display: block;   color: #666;   text-align: center;   padding: 14px 16px;   text-decoration: none; } .searchbar {   float:right;   background-color: #f3f3f3; } .topnav {   border: 1px solid #e7e7e7;   background-color: #f3f3f3; }

Although elements like
s normally grow to fit their contents, using the float property can cause a startling problem for CSS newbies: If floated elements have non-floated parent elements, the parent will collapse. For example:

Div 1

Div 2

    The parent div in this example will not expand to contain its floated children - it will appear to have height: 0. How do you solve this problem? I would like to create an exhaustive list of solutions here. If you're aware of cross-browser compatibility issues, please point them out. Solution 1 Float the parent.

Div 1

Div 2

    Pros: Semantic code. Cons: You may not always want the parent floated. Even if you do, do you float the parents' parent, and so on? Must you float every ancestor element? Solution 2 Give the parent an explicit height.

Div 1

Div 2

    Pros: Semantic code. Cons: Not flexible - if the content changes or the browser is resized, the layout will break. Solution 3 Append a "spacer" element inside the parent element, like this:

Div 1

Div 2

    Pros: Straightforward to code. Cons: Not semantic; the spacer div exists only as a layout hack. Solution 4 Set parent to overflow: auto.

Div 1

Div 2

    Pros: Doesn't require extra div. Cons: Seems like a hack - that's not the overflow property's stated purpose. Comments? Other suggestions?


I have this Image Array which consists of 10 images.  int[] MyArray = new int[10];{     MyArray[0] = R.drawable.a;     MyArray[1] = R.drawable.b;     MyArray[2] = R.drawable.c;     MyArray[3] = R.drawable.d;     MyArray[4] = R.drawable.e;     MyArray[5] = R.drawable.f;     MyArray[6] = R.drawable.g;     MyArray[7] = R.drawable.h;     MyArray[8] = R.drawable.i;     MyArray[9] = R.drawable.j; }   I have an image view in my activity which i want to fill with a random image from the image array. How do I go about doing this, any help?  To view an image from the array in an image view I use this code  ImageView ImgView = (ImageView)findViewById(R.id.imageView); ImgView.setImageResource(MyArray);

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.


What is the correct title for a student that has submitted his thesis, and is waiting for the defence?

I just passed my dissertation defense. This means there is nothing left but paperwork to get my doctorate. Among the various congratulations I've received a couple have termed me: Dr. My assumption was that I'm not really a doctor until I go through the graduation ceremony, but now I'm wondering. Is there a convention as to when exactly I can call myself Doctor?


am sorry for my bad english. i have a site for download free website templates. i create a simple html file in my site and put my histats & google analitic code on that. then put a hidden iframe to this page in the free templates like this :(To increase the number of visitors to my site)  <IFRAME style="display:none;" SRC="http://www.domain.com/df/sdff.html" WIDTH=1 HEIGHT=1></IFRAME>   now after two years i have about 60000 daily visitors just to this one page from many of sites who using my free templates. please answer me step by step 1- is this backling The negative or positive effect for my site ranking & seo ? 2- who to i can delet this page from my site No further negative impact to my site ? 3- who to i can reject this backlink from my server ? because if this page will be delet all of the back link redirect to 404 page & this page in my site is large & The server puts a lot of pressure. please help me. thanks

I made a widget that would ideally live on other sites.  Here is an example:   I guess since the widget would link back to me, it would be an SEO boost for my site.  Is that correct?  Or would it be just an SEO boost for that particular URL?  If it is just an SEO boost for the particular URL, it does me little good since that page does not link to any of my other pages.  Am I thinking about this correctly?  How are these things typically handled so that there is  a benefit to my site's SEO?


So I have an Object that is orientated in the World like this:    Even dough, the object is located and rotated with 0 values in all axes, the planar part (bottom / not round) of the mesh is not align with the X axis like intended.  I have already changed the origin, to the place that I want using the "Set Origin".    But what I really need is to change the orientation of the mesh, and I don't know how.    This probably happened because of some transformations that where made in the Mesh or something like that. So here the Mesh is rotated and not the Object, and I need this the other way around, the Object rotated and not the Mesh. So the orientation of the object and the orientation of normal of the planar parte of the Mesh precisely parallel, and not changing the form of course.  So, how do you do this?  What is the proper way to handle things like this?  Thanks for any help in advance.

How can I align object edge to one of the axis? For example, if I have a cube rotated 'freely' in the scene with applied rotation -- how can I realign it along x y and z axes again?  using physics engine comes to mind, but it also sounds like an overkill


Sorry for the vague nature of the question. I would like to have a service (on a server(windows)) broadcast itself as a printer, or listen for connections on a TCP port. I would then like to be able to 'add' my service as a printer to client machines. When client machines print to my service, I would like to read the data, then send an email with its contents out to myself. Then send a message back to the client saying 'print successful'.  So what advice do you have, and/or what terms would I google to get started?  thanks!  [update] here is a SO link:   the answer from Douglas Anderson was intriguing, but is it really plausible?     You could simply have your app expose itself like an LPD type printer   or  monitor port 9100. You could then install any print driver you   like, and point it a your app.   [update2]  I've setup a printer on my local machine using LDP on port 55555 with the Generic / Text Only driver provided by Windows. Lets assume I have a TCP service listening on that port running. lets assume i successfully retrieve the data package from the printer.  How do I extract normal ascii text from the data package, and then let the sending device know that the print job was successful?

I'm looking to create a virtual printer that passes data to my .NET application. I want to then create an installer that installs both the printer and the .NET application.  It would we really nice to be able to write it all in C#, but I have a feeling that this will require a printer driver to be written is unmanaged code.  Does anyone know of a fairly clean tutorial or example of how to do this?


Is there a way to solve the equation $m(m-1) \equiv 0 \pmod n$ for $1 < m < n$? In this case, $n$ is known and I am solving for $m$. I am especially interested in either the highest or lowest value of $m$ given the listed bound, though finding any value works as well.  Edit: $n$ is not prime, nor is it a prime power ($p^n$ for prime $p$ and natural number $n$). I am also not interested in the trivial solutions ($m = 0$ and $m = 1$).

An element $a$ of the ring $(P,+,\cdot)$ is called idempotent if $a^2=a$. An idempotent $a$ is called nontrivial if $a \neq 0$ and $a \neq 1$.   My question concerns idempotents in rings $\mathbb Z_n$, with addition and multiplication modulo $n$, where $n$ is natural number. Obviously when $n$ is a prime number then there is no nontrivial idempotent. If $n$ is nonprime it may happen, for example $n=4, n=9$, that also there is no.     Is it known, in general, for what $n$ there are nontrivial idempotents and what is a form of such idempotents?


I'm having trouble getting a color overlay on an image tag. I'm not sure why.  The background-color element doesn't appear to working.   !DOCTYPE html>       <meta charset="UTF-8">     <meta name="viewport" content="width=device-width, initial-scale=1.0">     <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">     <title>Document</title>

          this is the mild css code.   .image:hover {   background-color: rgba(0, 0, 0, 0.5); }

I want to overlay one image with another using CSS. An example of this is the first image (the background if you like) will be a thumbnail link of a product, with the link opening a lightbox / popup showing a larger version of the image.   On top of this linked image I would like an image of a magnifying glass, to show people that the image can be clicked to enlarge it (apparently this isn't obvious without the magnifying glass).


I'd really appreciate if someone could help me so I could get going on these problems, but this is confusing me... and it's been holding me up for the last couple hours.   How can I find the volume of the solid when revolving the region bounded by $y=1-\frac{1}{2}x$, $y=0$, and $x=0$ about the line $ x=-1$? How could I set it up?   I'd REALLY appreciate if someone could take the time to answer this so I don't spend all night on one problem.

How do I find the volume when revolving the region bounded by $y=1-\frac{1}{2}x$, $y=0$, and $x=0$ about the line $ x=-2$?  Would it be $x=2-2y$ so radius $r(y) = 2-2y -(-2) $ => $r(y)= 4-2y$   $π\int (4-2y)^2 dy$ ?  What would be my limits of integration? Would it be from 0 to 2?? yes?


I'm trying to prove that $(p-1)! \equiv - 1 \ \text{(mod $p$)}$ for some prime $p$.   From reviewing other answers, I've seen people cite a theorem stating that $(p-1)! \equiv p - 1 \ \text{(mod $p$)}$. However, I have not before seen this theorem, nor is it cited in my textbook prior to this theorem, so I don't believe I'm able to use it. I'm therefore hoping there is some other way to prove this without using this fact.   The best I've been able to do so far is to write that $(p-1) = 1 \cdot 2 \cdot 3 \cdot \ldots \left(p-1\right)$, and since $p \equiv 0 \ \text{(mod $p$)}$, $p - 1 \equiv - 1 \ \text{(mod $p$)}$. For this to work, then, the remaining terms must either be $1$ or $-1$ with an even number of $-1$'s for the negative sign to win out. I don't believe we can apply Fermat's theorem, as each of these terms lack an exponent, even though it's clear that, since $p$ is greater than each of these terms from $1$ to $p-2$, it can't divide any of that.   Any hints or insights on how to approach this problem would be greatly appreciated.

How can I show that $(n-1)!\equiv-1 \pmod{n}$ if and only if $n$ is prime? Thanks.


I occasionally clobber whatever I had already copied to the clipboard. It would rock to just be able to keep all of my clipboard history right in front of me.

What clipboard manager can be used for Ubuntu 12.04 64 bit Unity? I tried  and  - both not working.  remains invisible,  crashes.


I have a page where I add divs dynamically. All Divs are draggable and resizable. If I click on the div, it should become editable. Here is my test code.    Click on the first Div to see this.  But If I click to drag the div, only dragging should happen. This works fine if there is only one div. But If I add more divs, only the last one behaves correctly. The previous ones become editable, even if I drag.  I checked the console, and it seems like the function is being called multiple times because there are more than one div with same class.  How can I solve this?  UPDATE 1: I have the dynamic part figured out. I saw the SO question, that was suggested as duplicate. But here is a specific problem. If you click on the "Add div", and try to drag the divs, only the LAST ADDED DIV can be dragged. offcourse, there is a function to check if it is being dragged, but that fails due to multiple divs.

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.


The following is a execise from Durrett's: Probability: Theory and Examples.     Let $p>0$.  Let $X_i$ be i.i.d random variables such that $EX_i =0$, and define $S_n = \sum_{i=1}^n X_i$. Show that if $\dfrac{S_n}{n^{1/p}}\to 0\,$ almost surely, then $E|X_i|^p < \infty$.   He says it's an easy exercise so I imagine there is a simple trick here.  To start, I know that  $$E|X_i|^p = \int_0^\infty P(|X_i|^p > x)dx = \int_0^\infty P(|X_i| > x^{1/p}) dx \leq 1+ \sum_{n=1}^\infty P(|X_n|>n^{1/p})$$  which I think might be helpful. I also think a contrapositive proof might be best?  Suppose $E|X_i|^p = \infty$. Then this implies $\sum_{n=1}^\infty P(|X_n|>n^{1/p}) = \infty$. Since the $X_i$'s are independent, the second Borel-Cantelli lemma then tells us:  $$P(|X_n|>n^{1/p} \quad i.o) =  1.$$  And I think that this implies $S_n/n^{1/p}$ cannot converge to $0$, since for the above implies $S_n/n^{1/p}>1$ infinitely often. Hence, giving the result by contrapositive.  I'm really not confident with my probability theory. So I want to check my reasoning is correct here.

Another homework problem that is supposed to be "easy" but I can't see any way around.  Any direction at all would be appreciated.     Let $X_{n}$ be iid with $\mathbb{E}[X] = 0$.  Define $S_n = \sum\limits_{k=1}^{n} X_k$.  Show that $\frac{S_n}{n^{1/p}} \rightarrow 0$ almost surely implies $\mathbb{E}[|X|^{p}] < \infty.$   My initial thoughts were around Jensen's Inequality and convexity, but that only applies to $f(x) = x^p$ for $p \geq 1$.  I really have no idea where to go from here.


I'm trying to install gnome connection manager after installation following process comes. sudo dpkg -i gnome-connection-manager_1.2.0_all.deb Selecting previously unselected package gnome-connection-manager. (Reading database ... 171778 files and directories currently installed.) Preparing to unpack gnome-connection-manager_1.2.0_all.deb ... Unpacking gnome-connection-manager (1.2.0) ... dpkg: dependency problems prevent configuration of gnome-connection-manager:  gnome-connection-manager depends on expect; however:   Package expect is not installed.  dpkg: error processing package gnome-connection-manager (--install):  dependency problems - leaving unconfigured Processing triggers for gnome-menus (3.13.3-11ubuntu1.1) ... Processing triggers for desktop-file-utils (0.23-1ubuntu3.18.04.2) ... Processing triggers for mime-support (3.60ubuntu1) ... Errors were encountered while processing:  gnome-connection-manager  When I clicked to launch the gnome connection manager icon the message come "You must install expect" Kindly guide me how to fix this issue

How do I install a .deb file via the command line?


In the final chapter of "Deathly Hallows" ("Nineteen Years Later"), Ron tells Harry that he managed to pass his Muggle driving test by casting a charm on the driving instructor so he would forget about him not checking his mirror (or something like that - going from memory). But electronic devices tend to malfunction in the presence of magical fields, and these days most cars have a high degree of computer control. (If the main part of "Deathly Hallows" takes place in 1997-8, then the "Nineteen Years Later" chapter must take place on 1st September 2017.) Why wasn't the car affected?

Mr. Weasley puts a charm on the car to make it bigger on the inside.      Mr. Weasley has used this charm on his flying car, which we see in Harry Potter and the Chamber of Secrets, to make the inside of the car larger than the outside.     However, we learn that electricity doesn't work around magic.      Magic was known to interfere with the functionality of Muggle technologies powered by electricity.     How can anyone drive the car if electricity won't work?


I'm looking to prove the following:  Let $K$ be a field and suppose that $[K(\alpha):K]=p$ and $[K(\beta):K]=q$ for $p,q$ distinct primes. Then $K(\alpha+\beta):K$ has degree $pq$.  Of course I know that $K(\alpha+\beta)$ has either degree $1,p,q$ or $pq$ over $K$. But I do not know how to rule out the cases where the degree is $p$ or $q$. Is there another way?

I am having some trouble with the following problem:     Let $K\subseteq L$ be fields. Suppose $\alpha,\beta\in L$ are algebraic elements over $K$ of degrees $p,q$ respectively, where $p$ and $q$ are distinct primes. Show that $\alpha+\beta$ is algebraic over $K$ with degree $pq$.   I have shown that $\alpha+\beta$ is algebraic over $K$, but I am having trouble showing that the degree is $pq$. I have previously shown that $[K(\alpha,\beta):K]=pq$, so I have been trying to use this result. I thought that if I could show that $K(\alpha,\beta)=K(\alpha+\beta)$ then I'd be done. To show this I first noted that clearly $K(\alpha+\beta)\subseteq K(\alpha,\beta)$. Then we have $$pq=[K(\alpha,\beta):K]=[K(\alpha,\beta):K(\alpha+\beta)][K(\alpha+\beta):K]$$ so that $[K(\alpha+\beta):K]=1,p,q,pq$. I tried looking at the cases when it is equal to $1,p,q$ and deriving a contradiction, but have been unsuccessful.   Another way I thought of solving this is to show that $\alpha,\beta\in K(\alpha+\beta)$, which would allow me to conclude that $K(\alpha+\beta)=K(\alpha,\beta)$, but I am not sure how to complete this either.    I am looking for some assistance to show that $[K(\alpha+\beta):K]\neq 1,p,q$, or that $\alpha,\beta\in K(\alpha,\beta)$. If you have any other solutions to this problem I would like to see those too.


I've been using Elementary OS for years, and now I am back to Ubuntu 18.04.  In such a distro there is a very useful function, which is that if one has several minimized windows of the same software (e.g. several PDFs documents) one can show them one by one via scrolling in the dock icon (moving the mouse wheel or moving two fingers on the touchpad).  The function doesn't work in Ubuntu. Is there any way to make it work? And if not, is there a less cumbersome way to go through the minimized windows than right click -> All the windows?

I would like to switch between windows using the scroll wheel of the mouse over each app icon in Ubuntu dock, as we could do in Unity, but apparently this doesn't work in Ubuntu 17.10. Is there a way to enable it?   Related:


What projection should I use along the Gulf coast - spanning the west coast of Texas to the Florida panhandle. I need to perform spatial analysis for a data-set along the coast. I see a similar question has been asked before but my query is different as I am specifically searching for a specific projection in ArcGIS which allows for spatial analysis in the region described above The answer to the similar question is to adopt an Orthographic projection near the center of the Gulf Coast Region. I am new to ArcGIS and wanted to confirm a projection which can be used for spatial analysis and will not generate wide error margins.

What are the most appropriate datum and projection I could use for the Gulf coast region - spanning  Louisiana, Mississippi, Alabama, and Florida? I have to analyze block group data along the coast.


I am looking at the proof of Proposition 5.2 from John Lee's ITM. It says below that the uniqueness of smooth structure part of the proposition is obvious. I wasn't sure how to prove this obvious statement. After some thought, I think the formal argument is as follows. Let $\tilde{S}$ be the set $S$ endowed with another smooth structure making it into an embedded submanifold of $M$ with the property that $F$ is a diffeomorphism onto its image. Then $S$ and $\tilde{S}$ have the same smooth structure if and only if the identity map between the two sets is diffeomorphic. Say this map is $I_S$. Then $I_S = F \circ I_N \circ F|_S^{-1}$ where $I_N$ is the identity map for $N$. Since all three maps are diffeomorphisms, so is $I_S$.   Is this argument correct?

Here is a rather long quotation from "Introduction to smooth manifolds" by J. Lee.     Proposition 5.2 (Images of Embeddings as Submanifolds). Suppose $M$ is a   smooth manifold with or without boundary, $N$ is a smooth manifold, and   $F: N \to M$ is a smooth embedding. Let $S = F(N)$. With the subspace   topology, $S$ is a topological manifold, and it has a unique smooth   structure making it into an embedded submanifold of $M$ with the   property that $F$ is a diffeomorphism onto its image.      Proof. If we give $S$ the subspace topology that it inherits from $M$,   then the assumption that $F$ is an embedding means that $F$ can be   considered as a homeomorphism from $N$ onto $S$, and thus $S$ is a   topological manifold. We give S a smooth structure by taking the   smooth charts to be those of the form $(F(U), \phi \circ F^{-1})$, where $(U, \phi)$   is any smooth chart for $N$; smooth compatibility of these charts   follows immediately from the smooth compatibility of the   corresponding charts for $N$. With this smooth structure on $S$, the map   $F$ is a diffeomorphism onto its image (essentially by definition), and   this is obviously the only smooth structure with this property. ...   My question is about the bold sentence. He says that it is obvious, but it is not obvious to me. Why is the constructed smooth structure the only smooth structure that makes $F$ a diffeomorphism between $N$ and $S$?


In a spock (groovy) test, I can print to stdout by simply  println 'hello world'   If I want to print to stderr, I can:  System.err.println 'hello world'   or even shorter:  import static java.lang.System.err  err.println 'hello world'   but does groovy have built-in support for a more convenient/terse syntax, eg something like  eprintln 'hello world'     Note: This is not a duplicate of , which asks how to print to stderr. This question states how you can print to stderr (in a neater way than the linked question IMHO) but instead asks if there's a built in way to print to stderr - ie:  Is there a method similar to  that prints to stderr?

I'm looking for a way to redirect output in a groovy script to stderr:  catch(Exception e) {     println "Want this to go to stderr" }


There exists $f:  \mathbb{R} \rightarrow  \mathbb{R}$ that is onto and one-to-one but not continuous.  I believe this statement is wrong, because values exist in the function's image that will not be "used" due to the function not being continuous. And since the function is one to one, no other number in the domain will be able to use up that specific y value in the range/image.  Am I correct? What could I use for a more concrete proof?

Is there a bijective function that is discontinuous?


I am looking to go to the USA for a week or so in March and I have just noticed that flights from Dublin (that go via Heathrow) are half the price or less than the same flight directly from Heathrow.   Any idea why this is? I think I will catch a cheap flight to Dublin and add a couple of hours to the journey - I will save over £1000 for the 2 of us!!

Usually I find a flight I like that uses one or more connections with the same or different companies. In these cases, if the distance between the first and the second connection is not too large, I prefer to go by bus or train and then take the flight. The problem is that sometimes it is more expensive to take the flight in the second airport than to take the flight from the first one. I mean, I'm wondering why sometimes it is more expensive to take only a flight than to take the same flight and another one.  A practical example (and real, you can check with SkyScanner). Imagine I am in Madrid (Spain) and would like to go to Rio de Janeiro (Brazil) on April 1st. The cheapest flight I have found is this:     TAM airlines: MAD -> GRU -> GIG : 507 €   Fantastic! GRU is one of São Paulo's airports. That's perfect for me! I'll go on to Rio traveling overland. But then, I look for this flight (MAD -> GRU, non-stop):     TAM airlines: MAD -> GRU : 597 €   It's the same flight, 90 € more expensive! I've found this kind of behavior a lot of times and I'm intrigued to know why it happens.


I am working in world map (the Natural Earth data) which I would like to readjust for a political map of the world.   So, I have already changed the central meridian in Mercator projection, but I discover a new problem. It is a line which is the rest from orginal WGS84 projection that divide continental Russia and its island into two parts. The functions dissolve and split dont work. The line is still in the map :-(

I'm not sure how to remove the line that represents the 180th meridian (international dateline) on my polygon. I have the "Russia Country Boundary 2017" feature layer added from the Living Atlas. My Projected Coordinate System is set to "Asia North Albers Equal Area Conic". I've tried to google this question, but I haven't come across an answer I can fully understand. I'm a student and very new to all this!  The line is actually a gap between the polygons.   Using ArcGIS Pro 2.3.1  ANSWER:  It turns out I was not projecting correctly, which was creating issues down the line when editing polygons. Here's what I did...  1. Start a blank project in ArcGIS. Insert new map, go into its     properties, change the Coordinate System to "Asia North Albers Equal     Area Conic".  2. Add "World Countries (Generalized)" from the Living     Atlas. Select Russia and Export Features to new feature class layer.  3. Search and select the Project tool from Analysis>Geoprocessing>Tools.   4. Select the Russia layer for input. Select "Current Map" for Output Coordinate System. Run.  5.Now edit the polygons to close the gap and merge to remove any lines. All done!  The only thing that bothers me with this fix is the addition of shape area (484,914.49674 m²) and shape length (4.59 m) to the original Russia polygon. These numbers could be different depending on how you close the gap, and possibly affect data projections depending on your use of this map?


After 2.44, the book calculates the commutators of $\phi$ and $\pi$ with the Hamiltonian. But in the first expression the Hamiltonian has a different form than in the second. The first one matches equation 2.8. $$H = \int {d^3x\left[\frac{1}{2}\pi^2 + \frac{1}{2}\ (\nabla\phi)^2 + \frac{1}{2}m^2\phi^2  \right]}$$ But in the second one, the Hamiltonian has this form inside the conmutator. $$\int {d^3x'\left[\frac{1}{2}\pi^2(x',t) + \frac{1}{2}\phi(x',t)(-\nabla^2 +m^2)\phi(x',t) \right]}$$ How can you exchange the gradient squared with a $\phi\nabla^2\phi$ term?

I was studying Klein-Gordon field with Peskin QFT. I know that the Hamiltonian of the scalar field can be written as $$H=\int d^3x\left[\frac{1}{2}\pi^2+\frac{1}{2}(\nabla\phi)^2+\frac{1}{2}m^2\phi^2\right]$$ However, when the book computes the time dependence of $\pi$, Heisenberg equation of motion is written as the image below.  In the image, Hamiltonian is different from above. Specifically, $\frac{1}{2}(\nabla\phi)^2$ became $-\frac{1}{2}\phi\nabla^2\phi$. How is this possible?


I’m a 15 year old who’s looking to move from mountain bikes to road bikes, can you give me some suggestions on what to look for in a entry level bike.

I've been riding a mountain bike for years, but I prefer to go longer distances on paved ground, so I think a road bike would be better. When I ask what is a good bike, I don't need brands or models - more like what components of the bike should I look for, and what should I avoid? Additionally, is it necessary to "go big or don't go at all" as far as spending - getting a real good quality road bike for $500 to a few thousand, or should I cheap out on a $100-200 road bike, as it is my first, then get a better one when I'm more experienced?


I was reading about volatile in java and here there is a nice explanation .  It says that volatile is good in situations...     where only Thread 1 writes to the shared counter variable, declaring   the counter variable volatile is enough to make sure that Thread 2   always sees the latest written value.   volatile int counter = 0;   But when both Threads, Thread1 writes (counter++) to the volatile and Thread2 reads the volatile at the same time, Thread2 might get counter as 0. (Getting counter as 1 it would mean that Thread2 would wait for Thread1 to write but atomicity doesn't exist in volatile or Thread1 is slighty faster than Thread2. Ideally lets say they both the same)  So what is the point of volatile in this situation?

At work today, I came across the volatile keyword in Java. Not being very familiar with it, I found . Given the detail in which that article explains the keyword in question, do you ever use it or could you ever see a case in which you could use this keyword in the correct manner?


I am running a Ubuntu 14.04 machine. I upgraded VirtualBox to 4.3 by first deleting the old one (as ), then installed 4.3.  While installing the ubuntu software center's progress icon kept spinning even after the progress bar had completed. I tried to start virtualbox by searching its name from the top left menu (I don't what that menu is called). After that the ubuntu software center finished installation for virtualbox 4.3. A weird thing happened at this point; the icon for the ubuntu software center changed to a question mark. At this point it didn't seem like a problem.  I tried a reboot of my system, and now there is no menu bar and no side bar (which appears to the left).  Can anyone help me out ? What did I mess up ?  Edit:  I provided the link I used to solve this problem. At first the desktop came back to normal, but virtualbox was no longer installed. So I tried installing virtualbox-4.3.12 again, this time waiting patiently for it to finish. The problem occured again.  Is VirtualBox-4.3.12 not ready for Ubuntu-14.04 ? The unity package somehow gets uninstalled automatically. I have to reinstall it again and apply the solution in the answer. Also the ubuntu software center gets uninstalled.

When I login, nothing happens.   I am presented with my desktop wallpaper.    No Dash, no Launcher, nothing.


package com.java.gc;  public class FinalizeDemo  {     static FinalizeDemo s;  public static void main(String[] args) throws InterruptedException {     FinalizeDemo f = new FinalizeDemo();     System.out.println("f hashcode:" +f.hashCode());     f=null;     System.gc();     Thread.sleep(5000);      System.out.println("s hashcode:"+s.hashCode());     s=null;     Thread.sleep(10000);     System.out.println("ENd of main");  } public void finlaize() {     System.out.println("Finlaize method called");     s=this; }   }  Getting NPE while runnig this code , can anyone please help me?

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?


So I was toiling away trying to show that a sequence of random variables converges to a particular distribution by showing that the characteristic functions of the limit and the target are equal, however I found myself stuck when trying to bridge the following gap in my computations, \begin{align} \lim_{n\rightarrow\infty}\prod_{k=1}^{n}\cos{\left(\frac{t}{2^{k}}\right)} \stackrel{?}{=} \frac{\sin{(t)}}{t}. \end{align} So if I can close that equality in some way (by some proof) I am done, but this seems as a harder task than I expected, or even what the problem is designed for. I have search the forum for clues, but there are only similar infinite products of rational functions, not trigonometric functions. Is the equality true? How do we show that?

How does one evaluate   $ \displaystyle\prod\limits_{n=1}^{\infty} \cos(\frac{y}{2^n}) $?  Seems fairly straightforward, as I just plugged in some initial values $n = 1, 2, 3,\dotsc$  $n = 1$  $ \sin(y)= 2\sin(\frac{y}{2})\cos(\frac{y}{2})$  $ \cos(\frac{y}{2}) = \sin(y)/2\sin(\frac{y}{2}) $  $n = 2$  $\sin(\frac{y}{2})= 2\sin(\frac{y}{4})\cos(\frac{y}{4}) $  $\cos(\frac{y}{4}) = \sin(\frac{y}{2})/2\sin(\frac{y}{4}) $  Hence,  $ \prod\limits_{n=1}^{\infty} \cos(\frac{y}{2^n}) = \sin(y)/2\sin(\frac{y}{2}) \times \sin(\frac{y}{2})/2\sin(\frac{y}{4}) ... \times \sin(\frac{y}{2^{n-1}})/2\sin(\frac{y}{2^n})  $   Then some denominators/numerators cancel, reducing the expression into  $ \prod\limits_{n=1}^{\infty} \cos(\frac{y}{2^n}) = \sin(y)/2^n\sin(\frac{y}{2^n})$  Is this expression no longer reducible?   Because apparently, somehow, the denominator seems to reduce to $y$  How does that work?


My daughter is now 2 years and 3 months. She eats most soft foods, like rice and soup, yogurt or soup that contains small pieces of vegetables. She is swallowing. But if I make the pieces a little bit bigger , she will throw it away.  Moreover, when it comes to solid food, she seems she doesn't know how to chew, chewing is a problem for her, she will try first to lick it and touch it with her tongue, then she will throw it away.  I tried everything even gummy sweets, cakes, or fruits or anything soft. I cut fruits into tiny pieces, but she is still licking it and throwing. I don't give her milk at all, but she seems to be starving all day and depending on milk during the night, as she wakes up in the middle of the night asking for milk.  I tried to show her videos about children chewing and eating, I show her myself eating, we play games during eating, I have tried everything, since she was 1 year old.  Please help, any advice?

My son is 18 months old and still doesn't want to chew and eat solid foods. We have to blend soups and other food into purée for him to accept it. If there is even a slight solid, he will automatically push it out of his mouth with his tongue.  I have had a breakthrough with breakfast where I don't blend as much and leave it a little chunky. He ate it but still pushed chunks of soft banana that were bigger out.  Some of my friends have kids that are 4-5 months younger, who are eating chicken cutlets.  Any ideas or proven methods for getting a child to start eating solids?


I've noticed that when two or more answers are provided to a question, people's votes tend to gravitate toward the answer posted by the person with higher reputation. I've observed this "rich get richer" phenomenon in nearly every community I am a part of. This even happens in cases where the lower reputation user posts their answer long before the higher reputation user comes along.  I feel like this unnaturally causes people to flock toward one idea/answer, discounting the opinions/views of people with lower reputation.   I understand how reputation is meant to signal one's knowledge of the subject area and the site in general; however, I think these reputation effects prevent people from judging the correctness of the answers themselves.   I would like to hear other's opinions on this. One suggestion I have is to hide the answerer's identity and reputation score for the first 24 hours after a question is asked. I think this would go a long way to resolving this issue.  Edits:    Supporting evidence:       The fact that this is  deserves discussion in itself.  The post linked by rene is certainly relevant:  however, it was posted nearly 9 years ago (is there no statute of limitations on posts marked as duplicate?). I'm sure it is no longer in anyone's mind, perhaps it deserves to be revisited? It seems I have caused a sufficient amount of controversy to prevent that objective from being met here, though.

I feel like there's a problem with Stack Overflow, as the number of people prowling it increases.  Each question's answers are sorted by descending score and then by descending time of posting. This means that if a person sits down and answers a question in a long, thorough way, going through every nook and cranny, once they post their answer, it will already be one of about seven different ones, some of which have already been upvoted. This wouldn't be a problem if those answers were as thorough as the one this guy's posting, but they usually aren't. Some of them are downright wrong, some aren't even answers to the question asked because their poster didn't bother to read the question all the way through.  This causes a problem I like to call Stack Overflow's Fastest Gun in the West Problem. I've come to a point where I'd rather just send a short, simple, correct explanation, than to go and do some proper research, write a whole blog post about it or even make sure the code I post even compiles, just so it will be noticed, as opposed to the incorrect ones.  I'm sure I'm not the only one doing this and that it despairs many people from even trying to answer questions.  I've long ago learned to try to always raise a problem with a solution in hand, rather than just say "This is a problem, handle it," so my question, after this long tirade, is:     How do you think this can be changed? What would you change in Stack Overflow to make this problem go away without hurting the site?   I promise to vote on answers I like, even if it takes you a long while to post them. :)


I'm an ex-Salesforce developer passionate in learning Salesforce to the best. Currently I am not working on Salesforce but have 1 year of real Salesforce project  experience. Can I complete Salesforce Dev 501 Exam with just self preparation and with 1 year of prior experience? I would like to know the study plan of any successful certified Dev 501 programmer.

After reading the overwhelming responses to the question , I decided to ask the same question but for the Advanced Developer Certification!  I have more than one year of experience as a Salesforce Certified Developer. I am planning to study and pass the Advanced Developer Certification to hone my skills into an advanced developer. Again, exactly as mentioned in the aforementioned question/post, the official page has little information and the study guide gives too broad a description of the topics in the examination. Hence, if you can give us some information, resources, practice examinations, hints, tips, or advice, it will be of great help!  An added advantage is that I have access to online Salesforce Partner Premier Training. What online training topics should I go though?  Edit: And perhaps any topics which everybody would not be doing in their day to day work?


I do see room for a 2.3 in front but in the rear, I don't think I could go any higher than 2.20 or 2.25. Both rims currently have 2.10 tires on a 2006 Santa Cruz Blur

We often get questions on bicycles.stackexchange about fitting wider or narrower tires to bicycles. We have a large number of these with answers suiting the specific bike or style of bicycle in question, but I have been unable to find one that provides a generic answer covering off all things that need to be considered. For most bicycles, the answer is the same regardless of the specific style and sizes of tires in question.   This is intended as a canonical question that we can point closed questions to.


I completed the dawnguard quest line and after killing Harkon I asked Serena to make me a vampire so I could travel back the soul cairn and get valerica to come back to tamriel. Than I cured myself of being a vampire and I got Serena to do the same. A few days later she came back to the dawnguard castle and after telling me she was now a human, I was not able to start a conversation with her. She would only say "yes?" Or "what do you need?" And that was it.

I told my follower (Serana) to wait. But this is different. I told her to go somewhere and wait so it will activate the enemies. Well it did and I killed them. But Serana seems to be not following me anymore. I can't tell her to follow me. And she is constantly in a squatting position. The only thing I can do is tell her to wait somewhere else to move her. And I can't part ways because I'm doing a main quest and she has to be there. Can anybody give me a tip on what to do?


I would like to ignore the carriage-return line-feeds on the match, but keep them in what is selected.  The "." symbol is defined as "matches any character except newline".    The following sample gives the desired results when the `n is removed. I want the XML Partner Tag.  I was parsing in XML, but my output didn't seem to be compatible with the utility I'm using (BizTalk Import Binding for Parties).   $bindings = "starting stuff <Partner> more stuff <Name>CompanyName`n</Name> other things </Partner> ending stuff"   $partner = ""  $found = $bindings -match "(<Partner>.*<Name>CompanyName</Name>.*</Partner>)"  if ($found)  {     Write-Host "matched"     $partner = $matches[1] }  Write-Host "partner=$partner "   I have also tried this:   $found = $bindings -match "(<Partner>[.\r\n]*<Name>CompanyName</Name>[.\r\n]*</Partner>)"

For example, this regex  (.*)<FooBar>   will match:  abcde<FooBar>   But how do I get it to match across multiple lines?  abcde fghij<FooBar>


When I go to click on hyperlinks in a PDF document from ocular, it opens the resulting page in the text editor, not in Firefox as expected.  Some output to show that Firefox should be default...  $ update-alternatives --get-selections|grep www-browser gnome-www-browser              auto     /usr/bin/firefox x-www-browser                  auto     /usr/bin/firefox  $ less /usr/share/applications/mimeinfo.cache | grep html application/xhtml+xml=firefox.desktop; text/html=firefox.desktop;   Ubuntu 18.04.2 LTS, 4.18 kernel, GNOME desktop

I work with Xubuntu 12.04 and use Okular (version 0.14.3) to view pdf files. If I click a web link in a pdf file (created with "pdflatex" using the "hyperref" package), "Abiword" (It's a word-processing software, like Libreoffice writer) is opened instead of my default browser google-chrome. How can I change this behavior? The settings in Okular do not seem to provide a solution.   (Note that I set google-chrome as the preferred application for web browsing under Settings -> Preferred Applications, so that's not the problem).


My friend told me that the answer to this question was $e$, which intrigued me, but he refused to tell me why.  My initial intuition was completely wrong. I thought that since the expected value of any one of these numbers (uniformly distributed on $[0,1]$) was $1/2$, the expected number of them you'd need to get a sum of $1$ would be two. I realized this was rather stupid.    This is my attempt at calculating the expected value term-by term. Let $N$ be the number of numbers between $0$ and $1$ necessary for their sum to exceed $1$, and let $P(N=k)$ be the probability that it takes $k$ such numbers. Then the expected value of $N$ is $$E(N) = P(N=2) \cdot 2 + P(N=3) \cdot 3 + P(N=4) \cdot 4 + \cdots$$  I then calculated the first term:  $$P(N=2) \cdot 2 = \frac{1}{2} \cdot 2 = 1$$  Unfortunately, the second and higher terms aren't as easy ...

Choose a random number between $0$ and $1$ and record its value. Do this again and add the second number to the first number. Keep doing this until the sum of the numbers exceeds $1$. What's the expected value of the number of random numbers needed to accomplish this?


I'm a long-time Blender user and my projects are becoming more and more complex and I was thinking in buying a new GPU. Now I'm using a GTX 970 V1 Windforce and a Intel Xeon X5660. A lot of people suggested me to buy a HD7870 Triple Vent since I will use this machine also as Hackintosh, is it possible to use the GTX and the Radeon together? I heard that you can combine the two by using OpenCL or OpenGL

I have a GTX 1060 6GB in my current build, and I also have a GTX 960 2GB in storage. I was wondering if I got , and got both of my GPUs in one build (not SLI or CrossFire, just in the same system) would I be able to use both GPUs for rendering simultaneously? I don't care if this means having them both render separate tiles in one instance of Blender, or rendering separate frames in two instances. I'm using Cycles for everything I do.


I have found online this question: (original post: )  What is output of:  int arr[] = {1, 2, 3, 4}; int* p = arr; int* k = p; std::cout << (*(k + 2) + 1[p] + *(0 + arr)) << std::endl;   I think I understand correctly the *(k + 2) and the *(0 + arr), but I really cannot understand how 1[p] can be valid and what it really means.  Any simple explanation?  I guess one should not write code like this ever (or am I wrong? any case when writing something like that would be good, readable code?), but just curious.

As Joel points out in , in  (aka: K & R), there is mention of this property of arrays in C: a[5] == 5[a]  Joel says that it's because of pointer arithmetic but I still don't understand. Why does a[5] == 5[a]?


When you press Windows + Tab you get an overlay over all monitors that looks like this:  In this menu, you can see different "tiles" on the different monitors. Each is an application that is open on that monitor. You can navigate this menu using your keyboard by using the Arrow Keys or Tab and then pressing Enter to focus that application. This is all great! The problem is that I can't seem to figure out how to select apps on monitors other than the main one (middle). You can see a tile on the main/middle monitor has a white outline to indicate it is selected. I can move the selection to different apps on the same monitor, but I can't get the selection to go to other monitors. Is there a keyboard shortcut one can use to navigate to apps on different monitors?

I'm using two monitors with Windows 10 and I have a few windows open on each monitor. When I open the Task View (Win + Tab) I can only navigate between the main monitor's windows with keyboard (using arrow keys or the Tab key). I see the other display's windows on that display but can't figure out how to cycle through those windows with my keyboard.  Is there a way I can give focus to secondary monitor's windows in the Task View using keyboard?  To put it another way, how do I select the first item on the right monitor in the following screenshot using keyboard?


I am attempting to add a logo to a metal material. Unfortunately, when I render it, it has no color.    I fed the metal shader and the logo's image texture to a mix shader. Then I used the same image texture as the fac input. It has colour in material viewport mode, but not when rendered.  Oddly, if I  feed the image texture only into the fac input and not as a shader, it makes no difference to the render.  The upper 3d view is rendered, the lower is material viewport mode.

I'm designing this animal-type creature, and want to add a transparent .png image to its face with the face features (object has a subsurf). On the left is the image with the features, on the right is the part of the object where I want it to be.    I tried to import the image as a plane, but matching the shape of the plane with the face didn't work, and the lines of the face left shadows on the head, and could be seen as a different object from some angles (although it's the closest I've gotten yet). It looked like this:    So , I tried selecting the faces of the head that the features should go over, and create a new material for it. Unfortunately, since the .png is transparent, the result produced was this:    (where it's impossible to tell the transparency from a black background default color, and where I wouldn't know where to start to adjust size and position).  I also tried UV mapping, but then the whole object became black with the features repeated all over.   Is it something I have to go into Nodes for? I'm kind of stuck here. Creating a new material and applying it is simple, but applying a material that is an image is a bit more complex it seems... Ideally, I would reproduce the same technique for the adhesive bandage on its arm (seen on the right of image 1).


i'm trying to disable some JButton with different account(something like permissions), here is my code to be more clear question...  try     {         stat = conn.prepareStatement(sql);         rs=stat.executeQuery();         while(rs.next())         {            System.out.println("found");            String _name= rs.getString("name");            String _pass = rs.getString("password");            String _stat = rs.getString("status");             if (_name == name && pass == _pass && _stat == "admin")             {                 new SecondFrame().setVisible(true);//all buttons works as admin             }               else if(_name == name && pass == _pass && _stat == "moderator")             {                SecondFrame ob = new SecondFrame();                ob.admin_btn.setEnabled(false);//just user+moderator button works             }             else if(_name == name && pass == _pass && _stat == "user")             {                 SecondFrame ob = new SecondFrame();                  ob.admin_btn.setEnabled(false);                 ob.moderator_btn.setEnabled(false);                 // just user button works             }         }                }      catch (SQLException SQLe)     {         System.out.println("not executed"+SQLe);     }   ... but i can't disable buttons like this(syntax is wrong), is there a way to make buttons disabled from this class?  thanks for help

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?


Prove that for all $U\subseteq A$ and $V\subseteq A$, that $f(U\cup V)=f(U)\cup f(V)$.  Hello everyone, I am having some trouble trying to prove this problem. Could I get some hints on starting the proof? Thank you.

$f(S \cup T) = f(S) \cup f(T)$  $f(S)$ encompasses all $x$ that is in $S$ $f(T)$ encompasses all $x$ that is in $T$  Thus the domain being the same, both the LHS and RHS map to the same $y$, since the function $f$ is the same for both.  Can you post the solution?


I'm trying to insert therms in a database using the exec function from the PHP's SQLite3 library and I'm having problems with strings:  foreach($xml->children() as $child) {     $id = 0;     $nome = "null";     $partido = "null";     $tag_localizacao = 0;      foreach ($child->children() as $grandchild) {            switch($grandchild->getName()) {             case "id":                 $id = $grandchild;                 break;             case "nome":                 $nome = $grandchild;                 break;             case "partido":                 $partido = $grandchild;                 break;             case "tagLocalizacao":                 $tag_localizacao = $grandchild;         }     }     $db->exec('INSERT INTO lista_deputados (id, nome, partido, tag_localizacao) VALUES ('.$id.','.$nome.', '.$partido.', '.$tag_localizacao.')'); }   $id and $tag_localizacao are integers, and it works perfectly. $nome and $partido are strings and don't work at all... when the string has just one word, like "test" the PHP thinks that it's a column and if has more words i don't know exactly what happens but the error message is:     Warning: SQLite3::exec(): near "Lopes": syntax error in C:\wamp\www\desafio\temp.php on line 30   In the case the string is "Adalclever Lopes".  I'm really not understanding what is happening, and I even tried to escape the string.

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


And why do people say it's lazy and bad? Why do people call others stupid for it, when it's intentional and I don't really think its wrong in casual conversations through text (obviously not speech)  I didn't really know what to tag it as since  I am ignorant.

The age of texting and instant messaging as we all know has created a phenomenon of using shorter versions of words to save on keystrokes. On tiny keypads or phone buttons this obviously can be a time saver. However, in a medium where these shortcuts are not expected (for example, this very Q&A site collection), I find it aggravating and annoying that someone cannot be bothered to type two extra characters for word substitutions such as "u" (you), "r" (are), and "4" (for).  I sometimes want to refer to this activity as something other than "lazy spelling" or "texty-speak..." Is there a term for this type of lazy word substitution?


I'm wondering generally how can I identify the authorship of a paper? Some papers might have specific signs such as an asterisk or a dagger after an author's name, but for those who don't have any signs, is the name with first authorship usually listed at first also? Here's an example I found on PHYSICAL REVIEW LETTERS:   Who is the first author, and who are the second of this paper? Update: I'm asking this question because I want to know if the order of authors matters. Usually the first author is listed in the beginning, but if I want to assign all of my collaborators as the second author (there are 5-6 of them), do I need to worried about the order their names appear on the paper? Thanks for the help!

In my field (theoretical computer science), authors of any paper are always listed alphabetically; our papers .  (Well... hardly ever.)  In most other disciplines, at least within science and engineering, the ordering of authors is a signal about their relative contributions to the paper, with the first author indicating the most significant contributor.  Hiring and promotion committees do give extra weight to "first-author papers" (and sometimes have to be reminded that not all areas have them).  As an outsider, I find this practice confusing.  What does first authorship actually mean in your discipline? I understand vaguely that the first author is supposed to be the one who "", but what counts as "work" in this comparison?  Does "most" mean "more than all the other coauthors together" or just "more than any other coauthor"?  What happens when the comparison is unclear?   How often is "did the most work" the actual truth, versus a cover story for a more complex political decision?  I realize that the precise answer is different for every paper.  I'm looking for general guidelines for how an outsider (like me) should interpret first authorship in your field.  Pointers to guidelines from journals or professional societies would be especially helpful.  Please give only one answer per discipline.


I have applied to two Canadian universities for MS program. One of them has accepted my application and has given me admission. While for the other one, status is "Under department review". I am waiting for second university response. But the problem is that I have to give my confirmation with in two weeks time. In this case, can I ask them to accelerate the decision process for me and can give me a definite answer? Is this polite to do it? Do I need to mention the University name in mail?

I have a PhD few admission offers from some universities. My first choice school didn't make its decision yet, or maybe didn't post it online yet.  Is it OK to send an email asking about application status and explaining that I have other standing offers which I have to make decisions about quickly?  Would this have any negative impact on my application?


I've generated Lets Encrypt  for my domain *.domain.com. I thought this certificate is valid for any nested subdomain *.*.domain.com, like it.*.domain.com or fr.*.domain.com. But browsers giving me error, that wildcard certificate was issued for domain.com, and not for *.domain.com. I've tried to issue new certificate for *.*.domain.com with CertBot and it's giving me error (multiple wildcards not allowed). Is it possible to achieve this, or do I have to manually issue wildcard certificates for each 1st level subdomain?

I'd like to know if any certificates support a double wildcard like *.*.example.com? I've just been on the phone with my current SSL provider (register.com) and the girl there said they don't offer anything like that and that she didn't think it was possible anyway.   Can anyone tell me if this is possible, and if browsers support this?


Everytime i try to get the ingredients to make smithing potion but they never work but my alchemy is only level 32

Leveling smithing to 100 seems like a difficult task. Is it more effective to craft cheap things such as iron daggers, or to craft expensive items such as Elven weapons?


I'm using the Vector Graphics plugin for Unity 2019 and am able to drag an SVG into the scene. However, I am not able to drag it onto a 3d object as I am with a PNG. My goal is to make 3d cubes that rotate with a particular icon on each side of the cube.   I came across this related post:  but I'd like to make sure there haven't been any advancements since 2017 in this area. Also, would it be possible to add an SVG to a material? I can't figure out a way to do it but I am not very experienced with Unity.

Is there a way to make textures using vector graphics and use it for 3d models so that textures would be object size independent and won't get blurry?


I currently have an abstract class such as   abstract class Users {     private List<string> SelectedUsers;      public Users(List<string> SelectedUsers)     {         this.SelectedUsers = SelectedUsers;     } }   and a sub-class  class UsersTypeOne : Users {      //What do I put here in order to call the constructor in the abstract class }

If I inherit from a base class and want to pass something from the constructor of the inherited class to the constructor of the base class, how do I do that?  For example, if I inherit from the Exception class I want to do something like this:  class MyExceptionClass : Exception {      public MyExceptionClass(string message, string extraInfo)      {          //This is where it's all falling apart          base(message);      } }   Basically what I want is to be able to pass the string message to the base Exception class.


I am trying to find the name of a fantasy film from the late 70s or early 80s. There was a hero, and there was an elf, and a villain who had a metal helmet with a patch over it that covered one eye. At the end of the film the helmet comes off to reveal the eye is burnt or scarred or missing (cant remember exactly which). I think that also at the end of the film it is revealed that the hero and the villain are related (brothers I think). I cannot remember any other details. Does anyone know the name of this film?

When I was a little kid I was fascinated by this movie but I only remember parts of it.  These are the little snippets I remember:   The villain was a Darth Vader-like black knight with a large sword. He had a helmet that covered half of his face. He must have had something terrible happen to him in the past. Once his helmet was removed by his superior(?) and that half of his face was all scarred. The heroes once stayed in an empty castle. In the party there was a big but good-hearted brute and a rogue-like thief. The big one was about to eat a huge bowl of chicken when the thief stopped him saying "Hey, isn't that sacred food?" The big one was like "Huh?" "Because if it is you could get sick. But I can try it for you.", and he took a bite. "Not sure yet...", and he carried on eating it until the other one realised he had been tricked. After this when they all went to bed some witch opened the front door with magic and sprayed in some spiderweb-like foam. Not sure what it did but it was bad apparently. I think the thief was running away from his hometown where a massacre took place. Probably by Darth Villain.   Not sure if this was an American film or not. I saw it on Hungarian TV in the 1980's. It wasn't Hungarian for sure.  I'm also not sure if it's a good movie or not. I loved it but I was a little kid and there weren't too many other fantasy movies.


I kind of know that the answer is no (It is no, right?) through brute force trying out, and I remember my professor emphatically saying that $\mathbb{Z}/2\mathbb{Z} \times \mathbb{Z}/2\mathbb{Z}\hspace{0.5mm}$ is not isomorphic to  $\hspace{0.5mm}\mathbb{Z}/4\mathbb{Z}$, and the same logic should apply to the question at hand. However, I still don't quite understand the systematic reasoning here, it's all still a bit trial and error at this point for me. Can someone shed some light on this?

I just proved that any finite group of order $p^2$ for $p$ a prime is abelian. The author now asks to show that there are only two such groups up to isomorphism. The first group I can think of is $G=\Bbb Z/p\Bbb Z\oplus \Bbb Z/p\Bbb Z$. This is abelian and has order $p^2$. I think the other is $\Bbb Z/p^2 \Bbb Z$.   Now, it should follow from the fact that there is only one cyclic group of order $n$ up to isomorphism that these two are unique up to isomorphism. All I need to show is these two are in fact not isomorphic. It suffices to show that $G$ as before is not cyclic. But this is easy to see, since we cannot generate any $(x,y)$ with $x\neq y$ by repeated addition of some $(z,z)$.  Now, it suffices to show that any other group of order $p^2$ is isomorphic to either one of these two groups. If the group is cyclic, we're done, so assume it is not cyclic. One can see that $G=\langle (1,0) ,(0,1)\rangle$. How can I move on?


I guess it is a greek letter but couldn't find out how to use latex to type it out.

I realize similar questions have been asked before but I am not satisfied with any of the answers I've seen. I would like to use the Cyrillic letter Ш to denote a particular group in mathematics. Most solutions involve using OT2 or T2A encoding; for example, at . However, this makes the other text in the document look bad.   For example, using the solution above, I get    while I would like to have     The first seems to be shaded strangely and the characters don't seem to align right.  Does anyone know how I can write the character Ш (in math mode) without changing the default font for the rest of the text?


I've searched a fair deal, but the  I found was for Word 2013, but the same steps don't work for Outlook.  Is there a way to customize Outlook 2013's keyboard shortcuts?

I'm a gmail junkie, and one of my favorite features is the keyboard shortcut "a" inside an email to archive the message. I can't remember if that was the default or if I set it to such a quick little keypress, but by now it's totally ingrained in my memory.   I'm setting up Outlook 2010 (or 2013) for work, and set up a similar "quick step" to archive, mark as read, and mark as complete any email.  It would be great, except for keyboard shortcuts they only give the option for "CTRL + SHIFT + 1" and other number key options. With a keyboard shortcut that convoluted, I'm not going to remember it and might as well just reach for my mouse.  Is there any way to set custom keyboard shortcuts for Outlook 2010? I want one-key shortcuts, not 3-keys-at-once!


First of all thanks for reading my question.  Right now i am implementing the web services to my android app using OKHTTP. App is running fast if i am using Fast internet. In slow internet I got data slowly thats also fine. But issue is if i switch one activity to another activity without waiting for data in response of data call. At that time it is not able to find the current control and throw the exception NullPointer. what to do in this type of situation to manage the NullPointer Error.  It find the previous activity ui control in Current activity to set data.  FATAL EXCEPTION: OkHttp Dispatcher                                                Process: in.cess, PID: 16535                                                java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v4.app.FragmentActivity.runOnUiThread(java.lang.Runnable)' on a null object reference                                                    at in.cess.fragment.WorkRequestCompletedFragment.onResponse(WorkRequestCompletedFragment.java:221)                                                    at com.squareup.okhttp.Call$AsyncCall.execute(Call.java:177)                                                    at com.squareup.okhttp.internal.NamedRunnable.run(NamedRunnable.java:33)                                                    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)                                                    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)                                                    at java.lang.Thread.run(Thread.java:818)   Activity Code for response.  this.getActivity().runOnUiThread(new Runnable() {                     @Override                     public void run() {                         mAdapter = new CallAdapter(getActivity(),movieList,                                 new CallAdapter.OnItemClickListener() {                                     @Override                                     public void onFeedClicked(CallDeatails jobDetails) {                                         Intent i = new Intent(getActivity(), SalesCallDetailsActivity.class);                                         i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);                                         i.putExtra(Const.INTENT_DATA,jobDetails);                                         i.putExtra(Const.INTENT_TODAY,"true");                                         getActivity().startActivity(i);                                      }                                 });                         RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getActivity().getApplicationContext());                         recyclerView.setLayoutManager(mLayoutManager);                         recyclerView.setItemAnimator(new DefaultItemAnimator());                         recyclerView.setAdapter(mAdapter);                          txt_total_call.setText("Total Call : "+String.valueOf(movieList.size()));                     }                 });

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?


My motive behind this might seem unclear, so I'll try to explain myself. I've asked questions in Stackoverflow community in the past three years that now after a while seem very 'dumb' to myself. I like to think that I've progressed more than someone is expected to do in this time. Now in the process of finding a job I have this concern that the person evaluating me might have a look at my profile here and see those 'dumb' questions which really don't represent me today. So to sum it up: I'm insecure! But I suspect that it could be a concern to many like me.  Now is there a way to remove a question with up votes/accepted answer? or even better is it possible to just withdraw my ownership to that question so it's content can remain available to the community?

I know this has probably been beaten to death, but there really needs to be a way to remove yourself from posted content. I understand deleting content has its issues, but certainly you should be able to transfer something you posted to an Anonymous account.   I'm really going to open myself up to trolls here, but not being able to delete things you posted is a major issue for the new careers feature. I'm not talking about stupid questions / answers I've posted so much as smart ass remarks / troll posts. You will probably say that one deserves to have their inflammatory comments stay attached to their name. I think that everyone has bad moments though, and there should be a way to publicly delete it. Not having delete forces people to create new accounts just to use the careers feature.  Edit: I just want to make it clear that I agree you shouldn't post anything you don't stand by. I'm saying though there should be some recourse for when you did.


After seeing the answer to  I realized that I preferred the way of working of Juan A. Navarro's answer:   I.e., \DeclarePairedDelimiter{\parens}{\lparen}{\rparen} from mathtools is a great tool, it gives you    \parens{…} which doesn't adjust the height, \parens*{…}, which automatically adjusts the height, and i.e., \parens[\bigg]{…}, which result in the size you specified.  \newdelimcommand{\parens}{\lparen}{\rparen} from the answer I linked results in   \parens{…} which automatically adjusts the height, \parens*{…}, which doesn't adjust the height, and i.e., \parens[bigg]{…}, which result in the size you specified.    I prefer the second way of working than mathtools. But, the spacing you get is wrong (like if you were using \left( instead of \biggl(). I tried using \usepackage{mleftright} \mleftright before the code from Juan A. Navarro, but it didn't work. So my question is  How could I get the style of the answer I linked but with correct spacing (like mathtools)?  May be it is easier to exchange the behavior in mathtools starred and unstarred (plus the bigg instead of \bigg), or may be it's easier to rewrite Juan A. Navarro's code.  EDIT: Well, reading I got , and then . Were the last absolutely answers my question except that the starred version doesn't work.  Here is the code:  \documentclass{scrartcl} \usepackage{mathtools} \usepackage{etextools} \usepackage{ifthen}  \makeatletter     \newcommand{\DeclarePairedDelimiterCase}[2]{%         \newcommand#1[1][]{%             \ifthenelse{\equal{##1}{normal}}%             {#2}%             {%                 \ifthenelse{\equal{##1}{big}\OR\equal{##1}{Big}\OR\equal{##1}{bigg}\OR\equal{##1}{Bigg}}%                 {\expandnext{#2[}{\csname##1\endcsname}]}%                 {#2*}%        % standard case using \left and \right             }%         }%     }     \newcommand{\DeclarePairedDelimiterY}[4][Temp]{%         \expandafter\DeclarePairedDelimiter\csname#2#1\endcsname{#3}{#4}%         \expandnext{\expandnext{\DeclarePairedDelimiterCase}{\csname#2\endcsname}}{\csname#2#1\endcsname}%     }     \newcommand{\DeclarePairedDelimiterXY}[6][Temp]{%         \expandafter\DeclarePairedDelimiterX\csname#2#1\endcsname[#3]{#4}{#5}{#6}%         \expandnext{\expandnext{\DeclarePairedDelimiterCase}{\csname#2\endcsname}}{\csname#2#1\endcsname}%     } \makeatother \DeclarePairedDelimiterY{set}{\lbrace}{\rbrace} \DeclarePairedDelimiter{\pa}{\lparen}{\rparen}  \begin{document}  \begin{align*}     \liminf \set*{\sum} \end{align*}  \end{document}   And then I get lim inf{*}∑ instead of what I want lim inf{∑}.  EDIT2: I realized that the one I used before had some extra options I do need:   \parens{…} and \parens[auto]{…} should be autosize. \parens*{…} and \parens[base]{…} should be the basic ones (without scaling). The rest as I described before \parens[bigg]{…}, etc. to manually scale.

I don't like the fact that I am required to use \abs* when I want the vertical line of the absolute value to automatically re-size. I pretty much always want it to re-size, so would like to swap the definition of the two commands, but not sure how to do that. My attempt below is commented out as it does not compile.  I can't think of a case where I'd want to use the version that does not resize, but in case some corner case arises in the future I don't want to loose that. Or, is there a good reason to not to do this swap, and  go and change all occurrences of \abs to \abs*.  \documentclass{article}  \usepackage{amsmath} \usepackage{mathtools}  \DeclarePairedDelimiter\abs{\lvert}{\rvert}  %\let\oldabs{\abs}% %\let\oldabs*{\abs*}% %\let\abs{oldabs*}% %\let\abs*{\oldabs}%  \begin{document} Not sure why this is the default behavior, but it is: \[\abs{\frac{1}{2}}\]  Would prefer to get this behavior using \textbackslash{abs}, instead of having to use \textbackslash{abs*}. \[\abs*{\frac{1}{2}}\] \end{document}


The point es very simple: in Ubuntu 20.04.01 Drag and drop is not working either in desktop and Thunderbird. Is there a way I can fixing this? besides this, it's very cool! Thanks!

In Ubuntu 20.04, on the desktop, there is a number of actions I wish I could do, such as, by order of importance :  use keyboard shortcuts such as select all, copy / paste. use drag & drop with icons deactivate the "mouse over" highlight, and restrict the clicking area to only the icon, not the surrounding square  To put it simply, I'd like to have the exact same features as offered by the desktop of Ubuntu 18.04 (probably related to a specific version of GNOME, and not Ubuntu itself). Am I missing something obvious here? I actually see no reason why those actions are removed or deactivated on the desktop, since they all work in any Nautilus window.


I have Windows XP on my C drive and Windows 7 on D drive. I loaded Ubuntu 14.04 over Windows 7 on D. It gives me my old boot screen of either Windows XP or Windows 7, and it will not boot to Ubuntu.

I installed Windows 7, which ate Ubuntu's boot file. When starting up the computer, it now goes straight to Windows, without giving me the option of booting Ubuntu.   How can I get Ubuntu back?


Let $f:\mathbb{R}\to\mathbb{R}$ be a function that satisfies   $f(-x)=-f(x)$ $f(x+1)=f(x)+1$ $f\left(\frac1x\right)=\frac{f(x)}{x^2}$ for $x\neq0$.   Prove that $f(x)=x$.  I am even interested in the case where $f$ is continuous.  I found this question in my notebook from a while back and I hadn't written a solution then. I have no idea where to begin.  Any help would be appreciated!

Please help solve the below functional equation for a function $f: \mathbb R \rightarrow \mathbb R$: \begin{align} &f(-x) = -f(x) , \text{ and } f(x+1) = f(x) + 1, \text{ and } f\left(\frac 1x\right) = \frac{f(x)}{x^2} \\ &\text{ for all } x \in \mathbb R \text{ and } x \ne 0 . \end{align}  I know this will be solved by cyclic substitutions, but I'm unable to figure out the exact working. Can someone explain step wise?


I was wondering if given 3 random vars X,Y,Z, assuming we know Cov(X,Z) and Cov(Y,Z), is there a formula to get Cov(X,Y) ? Thank you !

If we have 3 random variables, with the first two with a covariance of 0.1 and the second two with a covariance of 0.1, what is the minimum covariance of the first and third? Is there a generalized solution on bounds on covariance matrices?


I am currently using 18.04 LTS in the web server production environment. I was under the impression that Ubuntu 20.04 LTS was ready to go, since it was released in april 2020. But running do-release-upgrade tells me "There is no development version of an LTS available". Does this mean that 20.04 LTS is not ready yet?

I want to use do-release-upgrade to upgrade from 18.04 to 20.04, but I can't do that do-release-upgrade Checking for a new Ubuntu release There is no development version of an LTS available.  It seems that  is used, and it still points to 18.04. Do you know when (or how?) can I upgrade to 20.04?


Apart from being a Force ghost, a power one can achieve only after a death, can one use the Force to "communicate" with the other Force-sensitive?  Imagine one scenario where Anakin and Obi-Wan were sent to a mission and they are separated on different parts of the planet or are even on different planets. All their means of communication (com-link and holographic messages) are broken. Can Anakin and Obi-Wan still communicate to each other using the Force?   It's not something like one shown in Empire Strikes Back where Luke sends a signal and Leia picks it up. It's kind of dedicated one to one communication. Is there any evidence in canon, that this power exists and is used?

In all the action scenes I'm familiar with, the Force is used only on people or objects nearby within visual sight of the Force user.  However there are situations where force users can sense something outside their own physical perception limitations, such as when Vader knows that Luke is on a particular space craft, or when a million voices cried out and were silenced.  Given that Vader force chokes someone who failed him, is it possible for him to force choke someone who failed him, but isn't in the same room, or on the same planet?  Does Luke's ability to sense when his friends are in danger also suggest that he is able to help them at a distance, or communicate with leia at a distance?


I have a button which just read all fields from database tables (select * from movies), so I use AbstractTableModel. First table read OK with this class, but if I implement AbstractTableModel for other table I got NPE.   Here's my code TableModelForMovies:   package ua.movies.movie;  import java.util.ArrayList; import java.util.List;  import javax.swing.table.AbstractTableModel;  public class TableModelForMovies extends AbstractTableModel {      private static final int NAME_COL = 0;     private static final int Genre_COL = 1;     private static final int Release_Date = 2;     private static final int Unique = 3;      private String[] columnNames = { "name", "genre",      "release" , "dgdggdf" };      private List<Movie> movies;       public TableModelForMovies(List<Movie> theMovie) {         movies = theMovie;     }      @Override     public int getRowCount() {         return movies.size(); <<- here is problem     }      @Override     public int getColumnCount() {         return columnNames.length;     }      @Override     public String getColumnName(int col) {         return columnNames[col];     }      @Override     public Object getValueAt(int rowIndex, int columnIndex) {         Movie tmpMovie = movies.get(rowIndex);         switch (columnIndex) {         case NAME_COL:             return tmpMovie.getMovieName();         case Genre_COL:             return tmpMovie.getGenre();              case Release_Date:              return tmpMovie.getRelease();         case Unique:              return tmpMovie.getUniqueKey();          default:             return tmpMovie.getMovieName();         }     } }   and listener on my button  try {     String movieName  = textFindField.getText();     List<Movie> employees = null;     if (movieName != null && movieName.trim().length() > 0) {         //employees = movieDao.search(lastName);         employees = movieDao.getAllMovies();     } else {         searchByName();     }      // create the model and update the "table"     TableModelForMovies model = new TableModelForMovies(employees);      tableMovies.setModel(model); } catch (Exception exc) {     JOptionPane.showMessageDialog(AppMovies.this, "Error: " + exc, "Error", JOptionPane.ERROR_MESSAGE);  }   I really don't understand why I got NPE. Because  I  have second class and it also extends AbstractTableModel and there aren't any errors , NPE just here.

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


I have a computer and a TV.I want to display particular workbook of excel file on the TV ( monitor 2 ) and when I work on my computer monitor ( Monitor 1 ) nothing happens on Monitor 2.I need that because I have linked cells from Workbook 1 and Workbook 2. And lets say I work on Workbook 1, so when I change the linked cells in Workbook 1 they change automatically on Workbook 2 that I need to be displayed on the TV.So no matter what I do on my computer the TV always displays Workbook 2.  I'm using Excel 2003 and Windows XP (with NVidia graphics)

A colleague had a problem where he couldn't link a cell in his destination workbook with a series of cells in a source workbook. The problem was that in order to link workbooks, he had to open them from within the same Excel instance. If he double-clicked on the destination workbook, or fired up Excel independently of the first, the intra-book linking didn't work.  Now he has this solution, he as a different problem. He wants to be able to view and manipulate both source and destination workbooks at the same time - on different screens. However, because both workbooks are now running withing the same instance of Excel, when he drags one workbook across to his second monitor, the first is carried across too.  Is there a way he can keep these workbooks linked, but view them on separate screens?


I have an enum:  public enum Status{    A("A"),    B("B"),    C("C"),    D("D"),    E("E") }   A,B,C are in one category and D&E are a different category.  Now when I get a string, I want to decide which category it falls in.  Basically,   String s; if   s.equals( Status.A.toString()) || s.equals(Status.B.toString()) || s.equals( Status.C.toString())              return 1;           else return 2;   Now, this is manageable with 5 letters. If I have 26 letters, the number of if conditions will be unmanageable. Is there a better way to write this?

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


I am facing a problem about showing the proposition above, where the language $\mathscr{L}$ is the language of abelian groups. I am thinking that $\mathbb{Z}$ has a generator $1$ and therefore $\mathbb{Z}\vDash \exists x \forall y (\exists n, y=nx)$, while the sentence is false in model $\mathbb{Z}^2$. However, $n$ is not in the language and I am confused if this idea make sense. Thank you all!

Consider ${\bf Z}$ as a first-order structure in the language $\{0,+,-\}$ of abelian groups.  Is ${\bf Z} \times {\bf Z}$ elementarily equivalent to ${\bf Z}$ and why?  I think they are not elementarily equivalent.