How can I get inside the castle safely?
How Do I get into the castle walls?
Find a value anywhere in a database Suggested edit review should show custom rejection reasons Somewhat similar to , but rather more limited: when Rejecting an edit, not only the count of custom rejection reasons but the actual text of the reasons should be shown, IMO. Just now I  on SO that tidied some code in a trivially correct and substantially superior way because it looked perfectly legitimate and I couldn't understand why anyone would bother with a custom rejection reason. As it turned out, it was code in a question, of course.  In this case, the rejection reason correctly identified the problem, and had I seen it, I would have been reminded of that aspect I had neglected to check. Let $P$ denote the quotient space obtained by the action of $\mathbb{Z}\backslash2\mathbb{Z}$ by the antipodal map $z\mapsto\frac{1}{z}$ on the riemann sphere $\hat{\mathbb{C}}$ (identified here with $\mathbb{C}\cup\left\{\infty\right\}$). I identify $P$ with the set:  $\left\{ z\in\mathbb{C}:\left|z\right|&lt;1\right\} \cup\left\{ e^{it}:0\leq t\leq\pi\right\} $   that is to say, I use elements of the above set as the representatives for the equivalence classes in $P$. I am looking for formula for a function $f:P\times P\rightarrow[0,\infty)$ such that $f$ is a metric on $P$. Specifically, I would like a formula for $f$ that I can evaluate by plugging in representative elements in the above set (or something like that, more or less).  Thanks in advance.  Edit: forgive me for sounding desperate, but I cannot make due with an explanation of how to obtain such a formula. I want the formula.   An analogy for you if I have yet to make myself clear: suppose I was asking for the area of a square with side length $s$. The answers I have received so far for my question are akin to saying "multiply $s$ by itself" or "use the area formula for a square". The answer I am looking for is akin to saying "$s^{2}$". I need the formula. And please, no expressions with differentials, nor matrices, or any of that. I need to know how to compute the metric by using the complex numbers in the indicated set that I have identified with $P$. Is openssl rand command cryptographically secure? I'm wondering if the openssl rand command produces cryptographically secure random bytes. For example when in need for a random password or token:  openssl rand -hex 32   The man page unfortunately does neither state it's cryptographically secure, nor that it's not.  On the one hand, I think this is openssl, its sole purpose is to do cryptography. On the other hand, the man page states something about reading and writing seed data instead of directly querying a CSPRNG.  So it is somewhat unclear for the end user. Does someone know? Unfortunately MyApp has stopped. How can I solve this? How to solve $y^2=3x^4+3x^2+1$ for integers. If $x,y \in \mathbb Z$ , then find all the solutions of   $$y^2=3x^4+3x^2+1$$       I was asked this question by my friend who said that he encountered this while solving another problem. I have tried several things but am unable to solve this question. Moreover, this has to be done using elementary methods only. So far, I have tried to factorize and use Pell's equation. At the end, I'm getting $$2y_{n} + (2x^2_{n}+1)\sqrt{3}=(2+\sqrt{3})^{n}$$   where $n \in \mathbb Z^{+}$    But I'm not able to figure out how to show a contradiction from here. Can anyone please help me out? Thanks. Alignment of equals sign in multiple align environments In ArcMap, when you export data to PDF it preserves the layering within the PDF so that you can turn on/off individual map layers (within the PDF itself).  When I export from QGIS to PDF, I don't appear to have the option for this.  Does QGIS support preserving layers when exporting to PDF?  Is there a special setting needed to enable this capability?  Or has anyone wrote a plugin for this feature? Elementary formula for permutations? Implementing switch cases I'd like to have command built around a switch-case environment in LaTeX, much like the example below:  \documentclass{article}  \usepackage{xstring}  \newcommand{\dothis}[1]{% \IfStrEqCase{#1}{{a}{so you typed a}     {b}{now this is b}     {c}{you want me to do c?}}     [nada] }  \begin{document}  \dothis{a}  \dothis{b}  \dothis{c}  \dothis{e}  \end{document}   My problem with it is that it requires the xstring package. Is there any other way to do this? Preferably without loading additional packages and avoiding disgraceful thickets of \if-\else-\fi statements? Usage of into vs in vs inside When should 'into', 'in' and 'inside' be used?  What are the differences between the three?   For example, what are the differences between the following statements?  Are any of them incorrect?        The frog jumped into the well.   The frog jumped in the well.   The frog jumped inside the well. Most people spend part of each day standing, and if they have normal anatomy their heads are over their heels in this position.  Even sitting or lying down, the head is higher than the heels (if not over the heels).  Yet the phrase "head over heels" is used in ways implying it is an unusual situation.  How did such usage come to be, and why does it persist?  Why is the more obvious "heels over head" not used? Why am I not able to shutdown, log-off and restart after an upgrade to Ubuntu 13.10? After the update neither my desktop (Asus) nor my laptop (HP) respond to the shut-down, log off or restart commands in the right top tool bar.  How do I fix the issue? What are 'user' and 'system' times measuring in R system.time(exp) output? Render semi-transparent volume with cycles I want to render an image of a fire in cycles, but as a png with a transparent background. Without a transparent background, the output image looks like this:    But as soon as I tick the "Transparent" checkbox under Render->Film, all the semi-transparent parts of the image are not rendered and it looks like this    which is clearly not what I want. I've tried to add a holdout shader or a transparent shader to my smoke domain material nodes, but it didn't help. I've only found answered questions for semi-transparent glass, but none for volumes. My node setup looks like this:    but the transparent shader doesn't do anything.  Has anyone an idea how to fix this?  Thanks  Edit: I've just changed the flow type to "Fire and Smoke" instead of "Fire" and now the semi-transparent parts render too, but I don't want the smoke. Is there a way to switch the mesh selection mode by a shortcut? "How" vs. "that" in "You know how we have pizza on Thursdays, right?" From time to time I hear sentences like this:      You know how we have pizza on Thursdays, right?   Here, how doesn't mean exactly how those guys eat pizza, it is something like "that" in this context.   So what is the difference between using how, that or just skipping the conjunction? No feedback when comment fails to post on Android 2.3.5 In the mobile theme on Android 2.3.5, comments that do not meet the minimum length will fail to post but no feedback message is displayed to the user.  The submit button changes to its active state, but nothing else happens. I am trying to solve the following exercise.      Assume that $m$ and $n$ are co-prime positive integers, and that $k$ is a field. Prove that the ideal generated by $x^{m} - {y^n}$ is a prime ideal in $k[x,y]$.   I tried the following approach : Consider the ring homomorphism ${\varphi}:k[x,y]\rightarrow{k[t]}$ defined by $\varphi(x) = t^n$, and $\varphi(y) = t^m$, and extend $\varphi$ to $k[x,y]$ to ensure that it is a ring homomorphism. Then the ideal $(x^m - y^n)$ is clearly contained in the kernel of $\varphi$. It remains to prove the reverse set inclusion. i.e. to prove that this ideal is exactly equal to the kernel of $\varphi$. I don't know how to go about this! Examples:        Why, I'd love to.   Why, of course!      I get the concept of starting a sentence with a word not completely related to the overall response, but this one seems to be a particularly odd choice&nbsp;— is there any semantic meaning I'm missing?