Where can I see the current server time on Stack Overflow?
Since the Stack Exchange sites run on one clock, and a clock that is not common to most of us (such as those of us in the US), can we display a clock with the site time (UTC) displayed somewhere on every page, such as at the bottom with the other text?  That way we are more aware of when the days turn over, and ecetera...  close votes, delete votes, flags, and normal votes would also benefit from this as well (thanks @Grace Note!)...    What do you guys think? yea or nay? thoughts?
How did Kylo Ren travel to the other planet in the TIE fighter? Help, i tried installing kaltools and my Ubuntu is messed up! I tried installing Kali Linux tools.  I started installing some tools and there were several things I had to "agree" to and one message said add users... something in terminal, and when I came back I saw terminal reporting removing a bunch of core programs that I needed. I canceled the process but I don't know if I should reinstall Ubuntu or not.  How can I repair my system? This is something I've been curious about since starting this whole 'meta' thing a couple years back.     Let's say a user posts a feature request.   Under what circumstances is the feature-request read by staff? If staff decline to do anything (I'd guess it's some sort of triage), under what circumstances is the feature-request reevaluated by staff?     Let's say a user posts a bug.    Under what circumstances is the bug tested? What generally determines whether a verified bug is actionable? (And/or what are the criterion for deciding what to do?)     For both of the above, would it be possible to see a general-but-relatively-detailed flow for what happens to these questions? Finite groups with exactly one maximal subgroup SQL group by day, show orders for each day I have an SQL 2005 table, let's call it Orders, in the format:  OrderID, OrderDate,  OrderAmount 1,       25/11/2008, 10 2,       25/11/2008, 2 3,       30/1002008, 5   Then I need to produce a report table showing the ordered amount on each day in the last 7 days:  Day,        OrderCount, OrderAmount 25/11/2008, 2,          12 26/11/2008, 0,          0  27/11/2008, 0,          0  28/11/2008, 0,          0 29/11/2008, 0,          0 30/11/2008, 1,          5   The SQL query that would normally produce this:  select count(*), sum(OrderAmount)     from Orders     where OrderDate&gt;getdate()-7     group by datepart(day,OrderDate)   Has a problem in that it will skip the days where there are no orders:  Day,        OrderCount, OrderAmount 25/11/2008, 2,          12 30/11/2008, 1,          5   Normally I would fix this using a tally table and outer join against rows there, but I'm really looking for a simpler or more efficient solution for this. It seems like such a common requirement for a report query that some elegant solution should be available for this already.   So: 1. Can this result be obtain from a simple query without using tally tables?  and 2. If no, can we create this tally table (reliably) on the fly (I can create a tally table using CTE but recursion stack limits me to 100 rows)? Shortcuts in Objective-C to concatenate NSStrings How would I verify the following double angle identity. $$ \sin(A+B)\sin(A-B)=\sin^2A-\sin^2B $$ So far I have done this. $$ (\sin A\cos B+\cos A\sin B)(\sin A\cos B-\cos A\sin B)  $$But I am not sure how to proceed. Often, TeX outputs underfull hbox and vbox warnings when running and in the generated log file. What are these and how can I get rid of them? On finding polynomials that approximate a function and its derivative (extensions of Stone-Weierstrass?) The Stone-Weierstrass Theorem tells us that we can approximate any continuous $f:\mathbb{R}^n\to\mathbb{R}$ arbitrary well on a compact subset of $\mathbb{R}^n$ by some polynomial. Suppose that $f$ is continuously differentiable, under what conditions can we guarantee we can find a polynomial $p$ such that $p$ approximates arbitrarily well $f$ and the partial derivatives approximate of $p$ arbitrarily well those of $f$ (on a compact subset of $\mathbb{R}^n$)? References are welcome. See below for my (probably naive) approach to the question.    It is straightforward to find conditions if $n=1$: Let $K:=[a,b]\subseteq\mathbb{R}$ and let $K_+$ denote some open cover of $K$. Suppose that $f:K_+\to\mathbb{R}$ is continuously differentiable and let $f'$ denote its derivative. Then, by Weierstrass's approximation Theorem we have that there exists a polynomial $q$ such that   $$||f'(x)-q(x)||\leq \varepsilon$$  for all $x\in K$. Choose some $y\in K$. For any $x\in K$ define  $$p(x):=f(y)+\int_y^xq(t)dt.\quad\quad(*)$$  By the Fundamental Theorem of calculus we have that $p'=q$. So for any $x\in K$  $$||f(x)-p(x)||=\left|\left|\int_y^x (f'(t)-q(t))dt\right|\right|\leq \int_y^x ||f'(t)-q(t)||dt\leq \varepsilon||x-y||\leq \varepsilon (a-b).$$  However, the above argument doesn't work in higher dimensions because the analogue of $(*)$ does not imply that $\nabla p = q$ (since not every vector of polynomials spans a gradient field). Can anyone suggest a way around this? That is, a way to to show that for continuously differentiable $f:\mathbb{R}^n\to\mathbb{R}$ and for any $\varepsilon&gt;0$, we can always find a polynomial $p$ such that   $$||f(x)-p(x)||+||\nabla f(x)-\nabla p(x)||\leq \varepsilon$$  for all $x$ in some compact set $K$? Feel free to add extra conditions on $K$, if it makes life easier. Suspend process without killing it So I've got a persistent program running in the background. Killing it just causes it to restart with a different PID. I'd like to suspend it (put it to sleep without actually killing it). Does kill -9 do this? If not, how should this be done? I am a computer scientist, and one of my professors today used the symbol $\propto$. I tried to search that using google, but it returns no results, and I do not even know its name.  So, I would like to ask, what does the operator $\propto$ mean? What is its name, and how is it used? The new search function allows quoted queries that include punctuation, and this is fantastic, most of the time. However, the search considers the punctuation as part of the word itself, so searches for "a test" will not show results containing a test,, a test., or a test?. The reverse is also true.  Is this the intended behavior ? &lt;--(space added so that behavior will show in results.)  It seems that the logical way to do fix this (while maintaining character search) is for queries with punctuation to match results with punctuation, while queries without punctuation to match either with and without.    Example:  vs     A more practical example is described in Arjan's answer below. I'm using the package braket for my physics notes, and this speeds things up a great deal but I'm constantly writing \ket{\psi} or \bra{\psi}, and because this specific pair of bra and ket appears so often, this gets repetitive and I would like a macro to speed this up.  However since the braket package works only in math mode, my attempt \newcommand{\ketp}{$\ket{\psi}}$ work when I'm writing in text mode, but when I'm writing in mathmode it breaks (unsurprisingly).  Is there any way I can get this command to work in both mathmode and textmode without having to define two different macros, one for each?    Thanks in advance for any help.  P.S. I'm certain this is a very simple question but I could find little to no explanation of this feature. If $G$ has no proper subgroup, prove that $G$ is cyclic of order $p$, where $p$ is a prime number.     I know that since $G $is a group with no proper subgroups, $g \in G$ is not just the identity. I don't know where to go from there. vertically align top line of item contents with item number \begin{enumerate}     \item This looks good.     \item       $\begin{aligned}         \mathrm{This} &amp;= \mathrm{is} \\                       &amp;= \mathrm{not\ nicely\ aligned}       \end{aligned}$     \item \begin{tabular}{ccc}             &amp; Neither &amp; is \\        this &amp; table.  &amp;    \\     \end{tabular} \end{enumerate}   It currently looks like this:    But I want it to look like this:    Vertically-aligned so that the top line of the ... item contents, lines up with the item number. A and B disjoint, A compact, and B closed implies there is positive distance between both sets Claim: Let $X$ be a metric space. If $A,B\in X$ are disjoint, if A is compact, and if B is closed, then $\exists \delta&gt;0: |\alpha-\beta|\geq\delta\;\;\;\forall\alpha\in A,\beta\in B$.  Proof. Assume the contrary. Let $\alpha_n\in A,\beta_n\in B$ be chosen such that $|\alpha_n-\beta_n|\rightarrow0$ as $n\rightarrow \infty$.  Since A is compact, there exists a convergent subsequence of $\alpha_n\;(n\in\mathbb{N})$, $\alpha_{n_m}\;(m\in\mathbb{N})$, which converges to $\alpha\in A$.  We have   $$|\alpha-\beta_{n_m}|\leq|\alpha-\alpha_{n_m}|+|\alpha_{n_m}-\beta_{n_m}|\rightarrow0 \;\;\;as\;\;m\rightarrow\infty.$$ Hence $\alpha$ is a limit point of B and since B is closed $\alpha\in B$, contradiction.  Is my proof correct? I feel as though I am missing something simple which would trivialize the proof. Darth Vader threw Emperor Palpatine to a pit. Well, , but unlike other times, Palpatine wasn't injured or unconscious when he was thrown.  Why didn't he simply prevent his fall using his lightsaber (I have seen such action in Star Wars: The Clone Wars TV series lots of time) and make his way out? Output of which command used for input to cd I would like to take the output of a which command, and cd to the parent directory. For example, say I have the following:  which someprogram   With output:  /home/me/somedirectory/someprogram   And I would like to cd to the directory that someprogram lives in:  cd /home/me/somedirectory   I'd like to accomplish this in one line. What is the most elegant, tricky, short way to do this? What are the biggest pros and cons of  vs ? Create UEFI bootable USB stick to install Windows AND Ubuntu from it I know how to make a UEFI bootable stick to install Ubuntu (explained ) and I know how to make one to install Windows 7 (, sorry). I guess for Win 8 the procedure would be similar, but I haven't looked into it.  I also know how to make a legacy bootable stick from which I can install Windows and Ubuntu using YUMI. I have failed so far though at creating a UEFI bootable stick that can do this. When I do a UEFI boot from my YUMI multiboot stick it gives me no option to choose between Ubuntu and Windows (hardly surprising I guess) and instead simply UEFI boots Windows (which I find kind of surprising to be honest but maybe this is due to the fact that I added the Windows image after the Ubuntu image and this simply replaced Ubuntu's EFI boot files).  So how would I proceed to create such a bootable stick?