Specifying the length of \hline $\left[\begin{matrix}     u(\lambda)\\\hline     v(\lambda) \\     \end{matrix}\right]$   $\left[\begin{array}{c}     u(\lambda)\\\hline     v(\lambda) \\     \end{array}\right]$   In the first code the \hline goes outside the brackets and in the second one there is unnecessary space. Please suggest some method to exactly place the \hline within brackets without extra space.
Horizontal line of custom length like an — Is there a way to get a custom-length horizontal line that appears like a "longer em-dash", if you will?
Is "mens" a valid word? I've been living in Ireland for almost a year now and I start noticing they use the word "mens" a lot. I can see it used in:   Shops, to denote the area where you can find men's clothes In sport, when they talk about "mens team".    My guess is just that they are lazy about the use of quotes, so that mens should actually be men's. However, there may be some rule I'm not aware of. So, is "mens" only limited to Irish English? When I'm allowed to use it? Hump, Rump, Lump, Bump I’m referring to the similar definitions of these four nouns – something raised and rounded.  Why do these four rhyming words have similar meanings?  I have not found very specific sources for these words on the  and . Hump is “probably from Dutch homp.” Rump is “from a Scandinavian source,” “from Old Norse rumpr” ultimately from Proto-Germanic “rumpo.” Lump is “perhaps from a Scandinavian source” and finally, Bump is “perhaps from Scandinavian,” “probably of North Germanic origin.”   Could these words come from the same root? Other than the fact that they all might come from northern Europe, the only hint I have in this direction is the following from , tracing the origin of Hump through Dutch, Middle Low German, Old Saxon and Proto-Germanic, to Proto-Indo-European *kumb-, *kumbʰ- (“curved”). Could this PIE root, which is not given in these online sources for any of the other three words, be a common root to all four words? I find myself looking at other –ump words and “seeing” a curved or rounded line: jump (a curved trajectory), grump (a downturned mouth), pump (the action of the pump handle), clump (a rounded clod of earth, not sharp), etc. Am I just seeing this because the words sound similar, or is there something more to my tendency? For example, the  suggests the origin of jump is "perhaps onomatopoeic (cf. bump)" although this view is not echoed on Wiktionary. Is it possible that these words do all share a common root and are simply onomatopoeic variations of each other? Are there other pairs or groups of words like these in English? (Wham! Bam! Ka-blam!) Does     this phenomenon have a name? Proof of inequality using AM-GM inequality prove that $x^2 + y^2 + z^2 \ge xy + xz + yz$  I tried proving it the way I prove $x^2 + y^2 \ge 2xy$. But it just doesn't seem to work. I tried using AM-GM. Should I be using GM-HM or AM-HM? I really don't know what the problem is and I'd appreciate any help and a full proof explanation. Thanks. How does the 'passwd' command gain root user permissions? How does Linux know that it has to give euid 0 (uid of root) to only certain process like passwd, setuid, etc.  If a process can gain root permissions, will it not lead to potential security breaches in the Linux platform?   For example, if I write a program that can can gain root user permissions like passwd, I may corrupt important system files like /etc/passwd, /etc/groups.   How does Linux manage to still be secure? Why is a conservative force defined as the negative gradient of a potential? I'm learning about work in my dynamics class right now. We have defined the work on a particle due to the force field from point A to point B as the curve Integral over the force field from point A to B. From math I know that if a vector field has a potential, we only need to evaluate the potential at point B minus the potential at point A to get the result of the curve Integral. In the text that I'm reading, it's explained that if the integral over a force-field is path-independent, then the force field $F = -{\rm grad}(V)$, where $V$ is the potential. Why is it defined as the negative gradient? Doesn't one determine the potential from $F$ mathematically. Why do we impose the sign on the potential? Typesetting A when a register is 1, B when 2, etc I have a register \count0=&lt;some-value&gt; and need to get the letter of the alphabet on the index of \count0. That is, if it is 1, I need an A, if 2, a B, etc.  Is this possible?  I'm reluctant sharing an MWE as it seems to overcomplicate things a bit:  \begin{tikzpicture} \node[regular polygon, regular polygon sides=7, minimum size=5cm] (A) {}; \foreach \i in {1,...,7}{     \count0=8     \advance\count0 by -\i     \node[circle, label=above:\scriptsize\the\count0, fill=black, minimum size=4pt, inner sep=0pt] (\the\count0) at (A.corner \i) {}; } \end{tikzpicture}   With the tikz package and the shapes.geometric tikz library.  This draws seven nodes labelled 1 .. 7 on a circle. I need to have A .. G instead of 1 .. 7. Correcting projection of 360° content onto a sphere - distortion at the poles I'm using the Autopano Giga 4.4 and Autopano Video Pro 2.6 to stitch and create spherical content, but I've recently moved into wanting to create 360° tours via Unity. I know this is partly a developers question, but if anyone out there can help me with the right specs for exporting a spherical image or video from Giga to use to create the image for the inside of the sphere on Unity, I'd appreciate it!  Experimenting with Premiere and FCPX to edit highlight reels of spherical content, I've had seamless experiences created. For some reason in Unity, the images appear to be stretched around the sphere wrong and it's creates issues on the top and bottom of the image:    The image shown is the bottom of the sphere. I'm using the Android platform to hopefully turn these tours into apps when completed. Thank you for any help! $X/{\sim}$ is Hausdorff if and only if $\sim$ is closed in $X \times X$ $X$ is a Hausdorff space and $\sim$ is an equivalence relation.  If the quotient map is open, then $X/{\sim}$ is a Hausdorff space if and only if $\sim$ is a closed subset of the product space $X \times X$.  Necessity is obvious, but I don't know how to prove the other side. That is, $\sim$ is a closed subset of the product space $X \times X$ $\Rightarrow$ $X/{\sim}$ is a Hausdorff space. Any advices and comments will be appreciated. What is meant by "Constant Amortized Time" when talking about time complexity of an algorithm? I've already tried clicking and holding the left button of my mouse, and it just won't work! Whenever I press it, it opens the game menu instead. How to create a soft or symbolic link? What are the most downvoted questions and answers on Stack Overflow, Server Fault, Meta, and Super User history to date?  Similarly, what are the most upvoted questions and answers on SO, SF, Meta, and SU to date? Workflow email with link to document in library Non constant analytic function from $\{z\in\mathbb{C}:z\neq 0\}$ to $\{z\in\mathbb{C}:|z|>1\}.$ Invalid selectOptions found. Use SelectOption type in Apex error with inner class object Contacts in Mavericks Messages display phone numbers instead of contact names Since updating to Mavericks the Messages app doesn't display the contact names for people I've been communicating with iMessage, it shows their phone number instead. My messages thankfully still stay synced between my iPhone and Messages on Mavericks. Missing settings in GNOME control center installed in Ubuntu MATE I installed GNOME Control Center following  to access Google Drive in Ubuntu MATE 16.04 LTS (MATE desktop environment 1.12.1)   The problem is GNOME Control Center is only showing language support, printers, firewall setup and backups... not online accounts or other settings.  This is what I get:  ~$ gnome-control-center gnome-online-accounts   ** (gnome-control-center:5744): WARNING **: Ignoring launcher landscape-client-settings (missing desktop file)  ** (gnome-control-center:5744): WARNING **: Invalid categories System;Settings; for panel software-properties-gtk.desktop  ** (gnome-control-center:5744): WARNING **: Ignoring launcher ubuntuone-installer (missing desktop file)  ** (gnome-control-center:5744): WARNING **: Could not find settings panel "gnome-online-accounts"   Any ideas?  Thanks! I want to resolve merge conflicts in my Git repository. How to do that ? I need to round the edges of this object.  The bottom edges are going to be rounded in conjunction with another object, so, I guess, this should be left out right now.  I tried using the bevel tool (and a bevel modifier) on an edge (series of Blender edges), but I got the problems you see on the images. When selecting all edges, the bevel doesn't know any limit and isn't applied symmetrically.  When selecting only the edges shown (or only the other ones), I can't proceed with the rest of the bevel, and strange little artifacts appear.  FYI: The top surface is derived from an icosphere.    Without the subdivision shown above, a stair comes into existence (bad):    Whole object: