I have trouble when I use the command \cal{B} , sometime the content after this command  will be change to arrow or triangle or similar unwanted symbol . this is the code:-  \documentclass{article} \begin{document} \cal{B}=(b_i)$ \end{document}   any help appricated
4121
Why does \cal{M}_n give “M>” in parts of my LaTeX file and works correctly in other parts?
15751
I saw the following syntax in a bash script:   &gt;$(command) &amp;   I know that the ampersand &amp; at the end makes a command run in the background, but I have never seen it in combination with the dollar sign plus the brackets around the command.  What does it do?
18666
amsfonts doesn't have lowercase caligraphic letters, so when you do $\mathcal{Hello World}$ you get some odd results. (Likewise for \mathbb I believe)  Now, what surprises me is not that there aren't lowercase mathcal letters, but that given this, the document compiles at all! What is going on that means that \mathcal{lowercase} is interpreted as being a string of random symbols? It seems what letter gets turned in to what symbol is constant, so this isn't just random: there's a reason why this happens as it does.  What is going on? Can some explain the details of what's happening beneath the surface that means that LaTeX interprets lowercase letters inside \mathcal as a variety of mathematical symbols?  [I don't understand enough to work out what tags would be relevant here...]
29000
What's the correct way to do division using a backslash? If I write $a/bc + d$, will that be equal to $(a/(bc))+d$?   Basically, if I place a slash, will I divide by what's directly behind the slash $(b)$, the term that's behind the slash $(bc)$, or everything after the slash $(bc+d)$?
43127
I saw two less than signs on this Wikipedia article and I was wonder what they meant mathematically.    EDIT: It looks like this can use TeX commands. So I think this is the symbol: $\ll$
35837
Many command-line tools (grep, flex, etc.) use the ^ symbol to denote "beginning of line" and the $ symbol to denote "end of line." When did this convention arise? It seems perfectly reasonable to reserve two characters for these purposes, but it's a bit odd that on modern keyboards the $ symbol is to the left of the ^ symbol.  Is this a completely arbitrary decision? Does this come from some older keyboard layout? Is this convention used because some older tool decided to do things this way?  Regardless of the answer, are there primary sources that document this?
86774
I would like to insert the below mathematical symbol, it looks like a big Delta but different. Is there command to obtain a similar shape?
18684
I did not know that latex had different symbol for opening and closing quotation marks. I've used it like "abc" every where and just realised that I really should have used ``abc". Is there anyway I can convert all the quotations to become like ``abc"? Doing it manually will take forever as I have a lot of quotations.
44469
Does anybody know how to make the following symbol in LaTeX? I think it is some calligraphic \mathcal{E}.     It is not anywhere in  and online font recognizers do not recognize it.   The general font in the book I got this symbol from, Introduction to Quantum Optics by Grynberg, is not very extraordinary: this is a formula containing the strange symbol:
46973
A solution I saw somewhere suggested to use   \usepackage{bbold} $\mathbb{1}$   which works well and I get what I want. However, now other symbols used to represent real numbers, natural numbers, etc look ugly.    I'd like them to look (without using bbold)    I'd like to only use that package to achieve that strange double one. Is there any way I can do that?
123086
Just out of curiousity.. Why are the line endings different for Windows and Unix.  I was looking around for the answer but not found.
119973
\begin{center}     \section*{\textcolor{blue}{Ukaaranta }}     \end{center}     \subsection*{Shabhu Harivat}     \addcontentsline{toc}{subsection}{shambhu harivat}  \begin{center}     \section*{\textcolor{blue}{Krostru Shabda}} \end{center}   I have a need to create something like this, however when I run this program, it gives error at the second \end{center}.  Funny but the same command works above. I did not do anything different, just copy pasted and changed the text. Similar commands elsewhere in the document work just fine. I have no clue why it's behaving like this.   Hit ? and R - enter and it gives the desired output but it's a pain to do that every time.
100298
Is there a way to typeset the symbol ":⇔" correctly in LaTeX (i.e. with the right alignment and spacing)?  I know that using :\Leftrightarrow or :\Longleftrightarrow gets me the symbol I'm looking for (more or less), but the spacing doesn't look right to me. Constructions using \iff or \colon didn't really seem to do the trick, either.   Do I have to define such a symbol myself (if so: how?), or is there a package proving this? Unfortunately, I did not find anything myself (especially because I don't know what to search for exactly; I got the description "defined to be logically equivalent" from Wikipedia, since I didn't even know the correct name).
30854
I have seen -- used in the compgen command.  For example:  compgen -W "foo bar baz" -- b   What is the meaning of the -- in there?
12151
What characters/symbols are allowed within the CSS class selectors? I know that the following characters are invalid, but what characters are valid?  ~ ! @ $ % ^ &amp; * ( ) + = , . / ' ; : " ? &gt; &lt; [ ] \ { } | ` #
114561
Could I get an example as to how these three elements (are these called metacharacters?) differ?  I know that * means all or nothing, but I am not sure if it's the right way to think about it. On the other hand . and ? seem the same. They match one character, right?
16260
Is there an editor or IDE (or a script) for substituting the TeX-Commands $ and $$ for opening and closing math regions into the corresponding LaTeX-Commands \(,\) and \[,\]? I'm sure there is a tool - and I'm searching for. I think, this will result in better readable code. A simple search and replace wont do that - but with regular expressions, that should not be problem. I simply do not want to invent the wheel a second time.