Similar questions have been asked here before, for example , but my point is slightly different. I have absolutely no issue with the total number of SE sites, on the contrary. However I don't think it makes sense to split topics if there is a high correlation between the users interested in these topics. Here is an example which I personally find a bit annoying:  The Stack Exchange site which I find most helpful and in which I am most active is Stack Overflow. Now as a professional software developer I am not only interested in coding issues but also in topics like project management or requirements engineering which become more and more off-topic in Stack Overflow.  To ask or answer such questions, I need to go to other sites like Project Management or Programmers. Especially the boundary between Stack Overflow and Programmers is far from being obvious.  I would find it much more convenient to have all software development related topics on one site. Of course this is my personal opinion but many questions, answers and comments give me the impression that lots of other users have the same issue.  Am I missing something?
I was just thinking that maybe if we have more Stack&nbsp;Exchange websites then each person would be a member of more different sites on average. Since the time a person can spend online on average is limited it means he will be spending less time on each website. But would this affect the quality of these websites? I'm not talking only about the quality answers given but also the number of answers given, the promptness. Won't these things go down?  I think that the rate of questions won't go down much because you need to know what you need to know. However, the average time a person spends browsing through these websites (and chances upon a question he can answer) would decrease. So are we creating too many different Stack&nbsp;Exchange sites?
Constructing a metric on a Lie Group Divergent infinite series $n!e^n/n^n$ - simpler proof of divergence? How to set the default format in text_format and hide the select? /**  * Implements hook_form_alter().  */ function MODULE_NAME_form_alter(   &amp;$form,   \Drupal\Core\Form\FormStateInterface $form_state,   $form_id ) {    if ($form_id == 'node_article_form') {     $form["body"]["widget"][0]['#allowed_formats'] = ['full_html']; // Your default format     $form["body"]["widget"][0]['#after_build'][] = 'MODULE_NAME_hide_format';   } }  function MODULE_NAME_hide_format(   &amp;$element,   FormStateInterface $form_state ) {   if (isset($element["format"]["format"])) {     $element["format"]["format"]["#access"] = FALSE;   }    return $element; } proving the inequality $\triangle\leq \frac{1}{4}\sqrt{(a+b+c)\cdot abc}$ How to count derangements? I was going through .Suppose that there are n persons who are numbered 1, 2, ..., n. Let there be n hats also numbered 1, 2, ..., n. We have to find the number of ways in which no one gets the hat having same number as his/her number. Let us assume that the first person takes hat i. There are n − 1 ways for the first person to make such a choice. There are now two possibilities, depending on whether or not person i takes hat 1 in return:  A) Person i does not take the hat 1. This case is equivalent to solving the problem with n − 1 persons and n − 1 hats: each of the remaining n − 1 people has precisely 1 forbidden choice from among the remaining n − 1 hats (i's forbidden choice is hat 1).  B) Person i takes the hat 1. Now the problem reduces to n − 2 persons and n − 2 hats.  From this, the following relation is derived: !n = (n - 1) (!(n-1) + !(n-2))  I have a hard time understanding point B and the equation derived. I was trying to understand with an example of 4 people named A, B, C and D and the corresponding hats A, B, C and D. Everyone of them are supposed to wear any hat except their own matching hat i.e. A can wear B, C or D.  If suppose A wears B hat so we will be left with only 3 people and 3 hats. So I can understand "(n-1)!(n-1)" part but what i didn't understand is part B(marked above). Can anyone help? It is my understanding that metals are a crystal lattice of ions, held together by delocalized electrons, which move freely through the lattice (and conduct electricity, heat, etc.).   If two pieces of the same metal are touched together, why don't they bond?   It seems to me the delocalized electrons would move from one metal to the other, and extend the bond, holding the two pieces together. If the electrons don't move freely from one piece to the other, why would this not happen when a current is applied (through the two pieces)? How to choose the number of hidden layers and nodes in a feedforward neural network? Is there a standard and accepted method for selecting the number of layers, and the number of nodes in each layer, in a feed-forward neural network? I'm interested in automated ways of building neural networks. Suppose $X$ is binomial $B(n,p)$. How can I find the probability that $X$ is even ?  I know $$P(X = k ) = \frac{ n!}{(n-k)!k!} p^k(1-p)^{n-k} $$  where $X=1,....,n$. Are they just asking to find $P(X = 2m )$ for some $m &gt; 0$ ? I am currently in the process of learning how to prove statements by induction. For the most part, I understand but I am at most clueless when it comes to prove some inequalities.  For example, I am having a hard time proving that: $n &lt; 2^n$ is true. (Even if it's clear that it is indeed true!)  In the induction step, I am stuck with: $n + 1 &lt; 2^{n + 1}$  I don't know what would be the assumption I should make from this statement.  Anyone could point me in the right direction? Thanks! How to highlight whole row and column under cursor in OpenOffice Calc? I need to work with large table. Something like in this illustation image will be helpfull for better orientation:    Is there some settings which makes this possible? I've often wondered why Stack Exchange has opted to keep the upvote/downvote buttons available for clicking on question/answers posted by the user. For instance:    Even though these buttons have no use for the user, why are they still placed on the post's left hand column? Moreover, the comments have no controls for flagging/+1'ing the user's own comment. What is the reason for this discrepancy? What benefit do the +1/-1 buttons provide to the user, even though they can't be used for anything? Configuring ADB for Nexus 4 on Ubuntu 11.10 I'm trying to deploy and test an Android app on my Nexus 4 from my Ubuntu 11.10 computer, but ADB doesn't recognize it. I think I need the Google USB drivers, but I cannot find instructions on how to install them on Ubuntu.  How can I install the drivers on Ubuntu 11.10 so that ADB will recognize my N4? In Python, I can compile a regular expression to be case-insensitive using re.compile:  &gt;&gt;&gt; s = 'TeSt' &gt;&gt;&gt; casesensitive = re.compile('test') &gt;&gt;&gt; ignorecase = re.compile('test', re.IGNORECASE) &gt;&gt;&gt;  &gt;&gt;&gt; print casesensitive.match(s) None &gt;&gt;&gt; print ignorecase.match(s) &lt;_sre.SRE_Match object at 0x02F0B608&gt;   Is there a way to do the same, but without using re.compile. I can't find anything like Perl's i suffix (e.g. m/test/i) in the documentation. Does borrowing from my 401(k) make sense in my specific circumstance? How to prove this binomial identity $\sum_{r=0}^n {r {n \choose r}} = n2^{n-1}$? Is it possible to activate an iPhone 4 without a SIM? I have forgotten my Facebook account password and also I have no access to the number which I use to log-in to Facebook account.   On this page (see the image below) they are asking for a government photo-ID to verify my account. The problem is that I don't have a driving license, voter ID card, passport etc. All I have is a school ID card but that hasn't worked for me. Is there any other way to recover my password? Probability density and distribution function I am new to probability course and find concepts very confusing. I am learning maximum likelihood estimation and as a starting point for that do we find the density or the distribution?   In general, do we find the distribution from density or is it vice versa and how does one find it? For example, for Gaussian distribution do we find the density of a variable or the distribution so as to estimate unknown parameter A in the case x[n] = A + w[n] where w[n] are uncorrelated gaussian noise. This may sound too trivial but I am really confused. In many contexts I have come across where pdf = prob. density function and in some areas I find pdf = prob distribution function !! How can I make a div not larger than its contents? I was just looking at the statistics for migrated questions in the  mod tools, and noticed this oddity:    The actual statistics, as visible to any 10k+ SFF user , are: 6 migrated to Worldbuilding, 2 to Literature, 2 to SFF meta, 1 to Movies &amp; TV, 1 to Writers, and 1 to Aviation.  Why is one of the meta migrations showing up with a blank icon rather than with the other?  Both migrated questions were closed as duplicates on meta. Both were migrated by 5 community members without mod involvement. One of the stubs on main has since been deleted, but so have the stubs for some of the other migrated questions. I can't think of anything to explain this discrepancy.