Is there a way to insert a character into a RegExp pattern?
How do you use a variable in a regular expression?
Blackboard bold variants for Greek letters It is common (or it used to be) to use a blackboard-bold variant of \mu to denote roots of unity in some mathematical papers.  However, despite searching (several times, periodically over several years) I have never been able to locate any package or technique that makes this possible, other than using Metafont or possibly hunting through the font definitions to see if it is something I can create a variant of (along the lines of the suggestions in Section 8 of the Comprehensive LaTeX symbol list).  Thus far, I haven't been sufficiently motivated to learn how to do any of this (although it probably would have resulted in a net time savings), and I feel like I cannot be the only person who would have tried.  Is anyone aware of an existing way to produce this character? I know that any group satisfying $x^2=1$ for all $x$ is abelian. Is the same true if $x^3=1$? I don't think it is, but I can't find a basic counterexample. I know I've seen somewhere how to typeset 1/2 as ½, but with arbitrary fractions (that is, a macro that takes two arguments and makes the first denominator and the second numerator...). Now I can't seem to find it.  How do I typeset an arbitrary fraction the same way as ½? Ubuntu 18.04 - Dell XPS13 9370 no longer suspends on lid close This was working perfectly on 17.10 but after upgrading to 18.04 yesterday, when the lid is closed the screen turns off but doesn't suspend properly.  I travel around a lot and immediately noticed the heat (and battery draining) when taking it out of the travel case.  I've tried uncommenting these lines in /etc/systemd/logind.conf  HandleLidSwitch=suspend HandleLidSwitchDocked=suspend   and restarted but didn't make any difference. iOS app stalls phone when on weak wifi sign I've recently noticed a bug on the Stack Exchange IOS app. When I open the Stack Exchange app on weak wifi, it hangs on the blue load screen as it launches and either crashes the app or the entire phone lags and didn't respond for about a minute.  I'm running iOS 8.4.1, I have the most up to date version of the app, and by 'weak' wifi I mean two out of four bars of strength. In case of a syntax error, pdflatex usually (in \errorstopmode) gets interactive and asks you what to do. I know I can press:   X to terminate S to enter \scrollmode (continue processing without stopping if further syntax errors arise, but stop for other errors) R to enter \nonstopmode (continue processing without stopping if further errors arise) Q to enter \batchmode (continue processing without stopping if further errors arise and suppress further output to the terminal)   Apparently, only the latter three (SRQ) can be provided implicitly by the respecive \...mode commands or the -interaction=...mode command line option. However, what I need is a mode that mimics the implicit pressing of X, that is, to make the pdflatex process terminate after the first error. I don't see advantages of using events over delegates, other than being syntactical sugar. Perhaps I am misunderstanding, but it seems that event is just a placeholder for delegate.  Would you explain to me the differences and when to use which?  What are the advantages and disadvantages? Our code is heavily rooted with events, and I want to get to the bottom of it.  When would you use delegates over events and vice versa? Please state your real world experience with both, say in the production code. Change the folder that Windows Explorer starts at In Windows7, when you open the Windows Explorer using the pinned Windows Explorer button on taskbar, it opens WE and points it to My Documents folder.  Is there a way to change this so it doesn't open My Documents, but rather "Computer" just as Windows+E keyboard shortcut does? Which is the best visualization for contingency tables? Which is best plot, from statistical standpoint, to show a , which is typically being analyzed by chi-square test? Is it a dodged barplot, stacked barplot, heatmap, contour plot, jitterred scatterplot, multiple lines plot or something else? Should one show absolute values or percentages?  Edit: Or as @forecaster suggests in the comments, the table of numbers is itself a simple plot and should be sufficient. What are all the member-functions created by compiler for a class? Does that happen all the time? Where can I find stock or custom ROMs for my Android device? Proof for maximal ideals in $\mathbb{Z}[x]$ I have been trying to prove the following theorem:      Every maximal ideal in $\mathbb{Z}[x]$ has the form $(p, f(x))$ where $p$ is prime integer and $f$ is primitive integer polynomial that is irreducible modulo $p$.    Idea: I tried to establish a homomorphism $\phi: \mathbb{Z}[x] \rightarrow \mathbb{F}$. Since $\mathbb{F}$ is a field it has characteristic $p$ and so integer prime p are mapped to 0 in $\mathbb{F}$. Hence $p\in \ker \phi$. Next we consider $\phi': \mathbb{Z}[x] \rightarrow \mathbb{Z_p}[x]$ and pick an arbitrary maximal ideal $M\in \mathbb{Z}[x]$. So, $\phi'(M)$ is maximal as long as $p \in M$ by correspondence. But now I am stuck at this stage and do not know how to proceed. I guess we might have to use primitivity given in problem but dont know how. How to simulate from a Gaussian copula? Suppose that I have two univariate marginal distributions, say $F$ and $G$, which I can simulate from. Now, construct their joint distribution using a , denoted $C(F,G;\Sigma)$. All the parameters are known.  Is there a non-MCMC method for simulating from this copula? Are fractions with prime numerator and denominator dense? Does "staff" take a plural verb? Which one of these two statements is correct?     Our staff do ...      Our staff does ...   And is staffs ever correct? Is $D_n$, the dihedral group of order $2n$, isomorphic to a subgroup of $S_n$ ( symmetric group of $n$ letters) for all $n&gt;2$? how do i get my stolen phone& pictures back? On 7 july 15 someone broke in my house and stole my galaxy note 3 it did not have service it has been disconnect for about 6mo now i would like to get my phone back because it had picture of me and my dad who died the day after father day this past june &amp; other family pictures that can not be replaced.how do i go about getting those back? How do I get to Orgrimmar from Silvermoon City at level 11? I have a level 11 Blood Elf and want to spend some of my honor points. I've heard that I could spend them in Orgrimmar, but the only problem is getting there.  How do I get to Orgrimmar from Silvermoon City? I'm not in a level 25 guild, so nobody can teleport me there. :( how to install the DDE to the ubuntu 20.04? I have installed the Ubuntu 20.04, and want now I want to install Deepin Desktop Environment (dde)  My steps are:   add the ppa and install using apt  sudo add-apt-repository ppa:leaeasy/dde sudo apt-get update sudo apt install dde    But during the command sudo add-apt-repository ppa:leaeasy/dde I get the following error:  $ sudo add-apt-repository ppa:leaeasy/dde  You can install deepin desktop environment by run  sudo add-apt-repository ppa:leaeasy/dde sudo apt-get update apt-get install dde ------ Ubuntu Bionic: https://drive.google.com/file/d/1xkQPb4tWocknuYeY-t41W--kz-9SSL0V/view?usp=sharing ------ Important Issue: Q: Can dde on Ubuntu 16.04? A: Sorry, the dde depends on qt version above than 5.6.      If you want to install dde, please upgrade to 17.04 or above.  More info: https://launchpad.net/~leaeasy/+archive/ubuntu/dde Press [ENTER] to continue or Ctrl-c to cancel adding it.  Hit:1 http://in.archive.ubuntu.com/ubuntu focal InRelease Hit:2 http://in.archive.ubuntu.com/ubuntu focal-updates InRelease                                      Hit:3 http://in.archive.ubuntu.com/ubuntu focal-backports InRelease                                    Ign:4 http://ppa.launchpad.net/leaeasy/dde/ubuntu focal InRelease                                      Hit:5 http://security.ubuntu.com/ubuntu focal-security InRelease            Err:6 http://ppa.launchpad.net/leaeasy/dde/ubuntu focal Release             404  Not Found [IP: 91.189.95.83 80] Reading package lists... Done E: The repository 'http://ppa.launchpad.net/leaeasy/dde/ubuntu focal Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.   I get the similar error with sudo apt-get update :  $ sudo apt-get update Hit:1 http://in.archive.ubuntu.com/ubuntu focal InRelease Hit:2 http://in.archive.ubuntu.com/ubuntu focal-updates InRelease                                       Hit:3 http://in.archive.ubuntu.com/ubuntu focal-backports InRelease                                     Ign:4 http://ppa.launchpad.net/leaeasy/dde/ubuntu focal InRelease            Hit:5 http://security.ubuntu.com/ubuntu focal-security InRelease Err:6 http://ppa.launchpad.net/leaeasy/dde/ubuntu focal Release   404  Not Found [IP: 91.189.95.83 80] Reading package lists... Done E: The repository 'http://ppa.launchpad.net/leaeasy/dde/ubuntu focal Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.   How can I install dde ? How to provide a file download from a JSF backing bean?