I just edited a typo in  which was rightfully closed as a duplicate. When I did, I saw that I could edit the automatically inserted text, possibly removing it. I didn't try to do so, but, should I be allowed to edit that text?  I'm going to post another question to test this.  EDIT: Yes, I was able to delete the automatically added text which linked my duplicate question to the "real" question... isn't that... not good? I guess you'd have to be pretty stupid to delete that text from your own question, but...
I've noticed the following happen a few times:   A user posts a question. The question is closed as a duplicate and the usual "Possible Duplicate" links are added at the top. The user promptly removes the duplicate links, even though the question is still closed as a duplicate. (excessive use of list items =P)   Now, I could understand this behavior if there was some dispute about whether or not the question was a duplicate, and the OP were to remove the links and post reasons why they disagree with the closing. However, I've noticed this happening without any attempt to defend the question (such as ).  In my opinion, no one should be allowed to remove the "Possible Duplicate" links as long as the question is still closed as a duplicate. The links should remain for the benefit of the community, so they can navigate to the duplicate questions and either post answers there or read them over and judge if the closing was actually fair. Once/if the question is reopened the links could be edited out if one so chooses.  I guess this is part discussion, part feature request:  Could the "Possible Duplicate" links remain un-editable for as long as the question is still closed?
A concept of the exterior derivative for functionals Meaning of $\int\mathop{}\!\mathrm{d}^4x$ What the following formula mean?  $$\int\mathop{}\!\mathrm{d}^4x$$  I know that this $\int f(x)\mathop{}\!\mathrm{d}x$ is the integral of the function $f$ over the $x$ variable, but the following $\int\mathop{}\!\mathrm{d}^4x$ leave empty the argument and also have the $\mathrm{d}$ elevated to the fourth power. What that mean?  Update.  In the Einstein-Hilbert action we have (note that I have understand that the other parts of the integral are relevant only after your answers, thus sorry.):  $$S=\frac{c^4}{16\pi G}\int\mathop{}\!\mathrm{d}^4x \, \ R \sqrt{-g}$$ Making sense of principal component analysis, eigenvectors & eigenvalues Use of "to lunch" vs."for lunch" Which is right?      I went to the (mall) to meet my parents for lunch / to lunch   This for a paper I am submitting for a writing assignment. I have heard "to lunch" is right, but is it right in this sentence please? What is the most elegant way to check if the directory a file is going to be written to exists, and if not, create the directory using Python? Here is what I tried:  import os  file_path = "/my/directory/filename.txt" directory = os.path.dirname(file_path)  try:     os.stat(directory) except:     os.mkdir(directory)         f = file(filename)   Somehow, I missed os.path.exists (thanks kanja, Blair, and Douglas). This is what I have now:  def ensure_dir(file_path):     directory = os.path.dirname(file_path)     if not os.path.exists(directory):         os.makedirs(directory)   Is there a flag for "open", that makes this happen automatically? Enlarged partition, filesystem still reports old size When writing my custom function I need to manually append node name to a taxonomy term link. To get the taxonomy term part done I use:    $link_uri = taxonomy_term_uri($term);   $path_alias = drupal_get_path_alias($link_uri['path']);   This works ok, now - I want to append node name ("/" . $node_name), but instead of raw string, I want the Pathauto transliterated output, as set in the URL alias configuration, for that node context.  What function should I use to mimic that output? I looked at hook_pathauto_alias_alter(&amp;$alias, array $context) but I'm not sure that's what I need. Play a Sound with Python Let $X$ be a beta distributed variable with parameters $a$, $b$. Let $Y$ be a beta distributed variable with parameters $c$, $d$. Let $Z = \max(X, Y)$.  Does anybody know of a fast way to compute the mean and variance of $Z$ given $(a, b, c, d)$?  $X$, $Y$ don't necessarily need to have beta distributions, but they should be similar -- in $[0, 1]$.  What I really want to find is a way to quickly approximate the distribution of the sample max of a bunch of random variables. Let $Z = \max(\{X_1, X_2,\dots , X_n\})$. If I know parameters (not necessarily beta-distribution) for $X_1, X_2,\dots, X_n$, can I quickly compute a set of parameters (same distribution as $X_i$) to form a distribution that closely approximates $Z$?    EDIT: To clarify, the purpose of this has to do with programming AI for board games. If we are evaluating a position in a chess game and we determine one move leads to a 60% chance of winning while all others have a 20% chance of winning, then we value the position as a 60% win. This is the minimax algorithm... However, what I'm curious about is whether this can be improved upon. In the simple case, we approximate: $$ \mu_c = \max(\{\mu_1, \mu_2,\dots, \mu_n\}) $$ where $\mu_c$ is the expectation from the current position and $\mu_i$ is the expectation from each of the sub-trees.  It seems like we should be able to do better than this. Can we find a function f that replaces max and closely approximates parameters for the distribution of the sample maximum? $$ (\mu_c, \sigma_c) = f\left(\{(\mu_1,\sigma_1), (\mu_2,\sigma_2), \dots, (\mu_n, \sigma_n)\}\right) $$ In this case, we still want $\mu_i$ to be the expectation from each of the nodes. However, $\sigma_i$ does not necessarily need to be variance/standard deviation; just a parameter that represents uncertainty.  Just as: $$ \max(\{a, b, c\}) = \max\left(\{\max(\{a, b\}), c\}\right) $$ We should expect: $$ f\left(\{a, b, c\}\right) \approx f\left(\{f(\{a, b\}), c\}\right) $$ So $f$ does not necessarily need to take parameters for more than two nodes.  One thing, however, is that $f$ should be relatively fast to compute. If the integrals must be calculated, I think doing double exponential integration might work well, but I'm not sure -- “Screen overlay detected” dialog? Turned off everything, doesn't work I started receiving the “Screen overlay detected” dialog when trying to change apps settings.  Tried to turn off all "draw over other apps" as it says here - , first without system and then with, but it still doesn't work.  Then, I restored apps to original settings and it just made a bigger mess, dialog continue appearing. Any way to go back to previous settings???  Thanks! PhD in Europe without scholarship from non-European homeland Lazy loading properties after an insert Proof that a Combination is an integer How do I make ditto marks? In France, students are taught not to repeat the same text twice when there is little difference between a line and the one below. It's a quick way to take notes.  I reproduced this effect by tinkering:    The code is as follows:  \documentclass[aspectratio=1610]{beamer}  \usepackage[T1]{fontenc} \usepackage[french]{babel}  \usepackage{amsmath, amsfonts, amssymb} \usefonttheme[onlymath]{serif}  \begin{document} \begin{frame} Lorsque le \og \textit{carreau carré} \fg{}   mesure: \begin{itemize} \item $\rm 1\,cm$ de côté, l'unité d'aire est appelée le \og \textrm{centimètre carré} \fg{} et est noté $\rm cm^2$; \item $\rm 1\,dm$ \hspace{1mm}'' \hspace{3mm}'' \hspace{8mm}'' \hspace{8mm}'' \hspace{5mm}''\hspace{8mm}'' \hspace{5.5mm}''\hspace{1mm} \og \textrm{décimètre carré} \fg{} \hspace{2mm}'' \hspace{2mm}'' \hspace{4mm}'' \hspace{1.5mm} $\rm dm^2$; \item $\rm 1\,m$ \hspace{3mm}'' \hspace{3mm}'' \hspace{8mm}'' \hspace{8mm}'' \hspace{5mm}'' \hspace{7mm}'' \hspace{5.5mm}''\hspace{1mm} \og \textrm{mètre carré} \fg{}  \hspace{9mm}'' \hspace{2mm}'' \hspace{4mm}'' \hspace{1mm} $\rm m^2$; \item etc. \end{itemize} \end{frame} \end{document}   How can I get the same effect more simply than by tinkering like I just did? Formation of ammonia from air and moisture On extended bicycle trips I sometimes slept under a plastic sheet, which helped with mosquitoes on hot nights. But there was a noticeable build-up of ammonia which made this almost impossible for more than an hour or so at a time.   Air is mostly nitrogen $(N_2)$ and there is always water (containing hydrogen) on a humid day. But I wonder about the mechanism for the formation of ammonia under these circumstances? There are (according to Wiki) trace amounts of methane and $H_2$ in the air. But methane and hydrogen (g) are I think pretty stable.   I wonder if the presence of exhaled air (containing $CO_2)$ could be a factor?  Thanks for any ideas. How can I evaluate $\sum_{n=0}^\infty(n+1)x^n$? How can I evaluate $$\sum_{n=1}^\infty\frac{2n}{3^{n+1}}$$? I know the answer thanks to , but I'm more concerned with how I can derive that answer. It cites tests to prove that it is convergent, but my class has never learned these before. So I feel that there must be a simpler method.  In general, how can I evaluate $$\sum_{n=0}^\infty (n+1)x^n?$$ In templates, where and why do I have to put typename and template on dependent names? What exactly are dependent names anyway?    I have the following code:  template &lt;typename T, typename Tail&gt; // Tail will be a UnionNode too. struct UnionNode : public Tail {     // ...     template&lt;typename U&gt; struct inUnion {         // Q: where to add typename/template here?         typedef Tail::inUnion&lt;U&gt; dummy;      };     template&lt; &gt; struct inUnion&lt;T&gt; {     }; }; template &lt;typename T&gt; // For the last node Tn. struct UnionNode&lt;T, void&gt; {     // ...     template&lt;typename U&gt; struct inUnion {         char fail[ -2 + (sizeof(U)%2) ]; // Cannot be instantiated for any U     };     template&lt; &gt; struct inUnion&lt;T&gt; {     }; };   The problem I have is in the typedef Tail::inUnion&lt;U&gt; dummy line. I'm fairly certain that inUnion is a dependent name, and VC++ is quite right in choking on it. I also know that I should be able to add template somewhere to tell the compiler that inUnion is a template-id. But where exactly? And should it then assume that inUnion is a class template, i.e. inUnion&lt;U&gt; names a type and not a function? Why is "that"/"which" omitted in this sentence? Shape of confidence interval for predicted values in linear regression I have noticed that the confidence interval for predicted values in an linear regression tends to be narrow around the mean of the predictor and fat around the minimum and maximum values of the predictor. This can be seen in plots of these 4 linear regressions:    I initially thought this was because most values of the predictors were concentrated around the mean of the predictor. However, I then noticed that the narrow middle of the confidence interval would occur even if many values of were concentrated around the extremes of the predictor, as in the bottom left linear regression, which lots of values of the predictor are concentrated around the minimum of the predictor.  is anyone able to explain why confidence intervals for the predicted values in an linear regression tend to be narrow in the middle and fat at the extremes? Are there any programs that will let me dictate (speech-to-text) to any program? Or at least to a text editor and text fields in Firefox.  I’m not interested in anything that uses an online service, it has to be on-device. It may be a commercial product.