Why is the path "//" valid any other combination results in "/"
How does Linux handle multiple consecutive path separators (/home////username///file)?
Mouse gestures for Unity desktop How to tell if a site is using Drupal 7 I know how to check , but is there a way to tell if a site is built with Drupal 7? Evaluation Symbol: Consistent Implementation Markdown in chat fails for multi-line messages iOS 9.2 double touch fingerprint sensor I was messing around this morning and found that if I quickly double touch (NOT double-click) the fingerprint sensor on my iPhone 6S+ (iOS 9.2), the current app (or the home screen) slides down to the bottom half-screen, showing a blurred home screen background on the top half.  It doesn't matter if I use a finger that the sensor recognizes.  It goes back to normal after about 8 seconds or if you double-touch again, but I can't figure out what this mode is for??  Is this a bug or some hidden feature I haven't heard about yet? In  (the original movie), Marty comes back from 1955 10 mins early to prevent Doc from being shot (which he fails at). He then rolls up to the Lone Pine Mall and sees himself hit 88 mph and shoot back to 1955 (again). Marty then carries on with this life as usual. What happens to the Marty that goes back to 1955 at the end of the film?  This obviously is a recursive problem where it would create another timeline and Marty would keep coming back 10 mins early to view another Marty zip back to 1955? I want to write applications for Ubuntu. I do not know much about programming but I want develop for Ubuntu. I am trying to learn Python right now. What do you think is the best way to develop apps for Ubuntu? Can you point me to some resources that can help me get started with developing for Ubuntu?  Related . What does the dot mean What cd/dvd burning software should I use? I have tried countless cd/dvd burning software on ubuntu 12.04 and none of them work for me,  any ideas guys?   I've tried tovidgui, bombono dvd,and mestelix, they are all so very confusing is there any program like dvdflick that is just straight to the point? We should make books of our best content! And that's a good idea!  We have a lot of high quality content here, certainly enough for a small book.   I'm not saying that it necessarily has to be integrated into the main site, but this is just a suggestion if anyone wants to implement it.   Stack Exchange probably could make money selling the physical books though. CC-BY-SA allows selling, as long as you allow others to make copies of your book, and credit the author.  What Wikipedia does is you can custom order any set of articles as a book (it even has a nice set of authors at the end, to satisfy the BY part of CC-BY-SA).  This could even tie into the docs feature. Infinite metric space has open set $U$ which is infinite and its complement is infinite Let $(X,d)$ be a metric space where $X$ is an infinite set. Prove that the space has an open set $U$ such that both $U$ and its complement are infinite sets.   I have considered if $d$ is the discrete metric, then one such $U$ exists. But if $d$ is not discrete, how do we find such $U$? Jordan form, number of blocks. Can I publish without affiliation? Autosegmental Representation in tikz-qtree This is what I want to achieve    and this:    But all I've been able to make with tikz-qtree is the following:  \documentclass[12pt,a4]{article} \usepackage[utf8]{inputenc} \usepackage{tipa,tikz,tikz-qtree} \begin{document}  \begin{tikzpicture} [baseline] \tikzset{frontier/.style={distance from root=90pt}} \Tree [.$\sigma$ [.O [ p ] ] [.R [.$\mu$ a ] [.$\mu$ : ] ] ] \end{tikzpicture} \begin{tikzpicture} [baseline] \tikzset{frontier/.style={distance from root=90pt}} \Tree [.$\sigma$ [.O [ p ] ] [.R [.$\mu$ a ]  ] ] \end{tikzpicture}   And this:  \begin{tikzpicture}[baseline] \tikzset{frontier/.style={distance from root=90pt}} \Tree [.$\sigma$ [.O [ l ] ] [.R [.$\mu$ a ] [.$\mu$ l ] ] ] \end{tikzpicture} \begin{tikzpicture} [baseline] \tikzset{frontier/.style={distance from root=90pt}} \Tree [.$\sigma$ [.O [ : ] ] [.R [.$\mu$ a ] [ l ] ] ] \end{tikzpicture} \end{document}   Which renders:    and    The important part here is the linking from the leaves to more than one parent (it would be nice if I had the option of making the line dashed too). Now, pst-asr doesn't quite achieve what I want it to. It's important that I have the moras ('mu's). (Also it's a pstricks package, which means I must typeset it in DVIPSPDF.) I have tried a bit of the forest-package (especially forest-GP1), but I can't make that work as I want either. Lastly, some have recommended xyling, but I find that package very difficult to use.  Any recommendations?  Thanks. Is there a name for an element $z$ such that $\,zx = z = xz\,$ for all $x$? Is there a general name for the following properties, (similar to the properties of existence of an additive identity, existence of multiplicative identity etc):   For any given set, the intersection with the empty set results in the empty set. For any real number, multiplication with zero results in zero. What is the difference between a URI, a URL and a URN? People talk about URLs, URIs, and URNs as if they're different things, but they look the same to the naked eye.  What are the distinguishable differences between them? Is Responsive Design good for web based software? We use unit length Quaternion to represent rotations. Following is a general rotation matrix obtained ${\begin{bmatrix}m_{00} &amp; m_{01}&amp;m_{02} \\ m_{10} &amp; m_{11}&amp;m_{12}\\  m_{20} &amp; m_{21}&amp;m_{22}\end{bmatrix}}_{3\times 3}\tag 1 $.   How do I accurately calculate quaternion $q = q_1i+q_2j+q_3k+q_4$for this matrix?Means   how can we write $q_i$s interms of given $m_{ij}$  accurately? Configuring, compiling and installing a custom Linux kernel Showing equality of sequence of holomorphic functions to limit function if converges uniformly locally I do not know how to proof following question:  Let $D$ be a domain in $C$.  ${{f}_{n}}$ be a sequence of holomorphic functions on $D$ that converges uniformly locally to a function non-constant $f$. Show that for each $z\in D$, there is a sequence ${{z}_{n}}\to z$ as ${{f}_{n}}({{z}_{n}})=f(z)$ for all sufficiently large $n$.  Actually, I know that I should use an assumption such as: ${{f}_{n}}({{z}_{n}})\ne f(z)$  Therefore, there is compact set    that  $\left\| {{f}_{{{n}_{k}}}}({{z}_{{{n}_{k}}}})-f(z) \right\|&gt;\varepsilon $  Then I think I have to use Montel theorem, but I do not know how to show the contradiction.