Take the 2-minute tour ×
TeX - LaTeX Stack Exchange is a question and answer site for users of TeX, LaTeX, ConTeXt, and related typesetting systems. It's 100% free, no registration required.

The braket package has convenient commands like \Braket and \Set, where | are automatically expanded vertically. This allows to easily typeset expressions like

\documentclass{minimal}
\usepackage{braket}
\begin{document}
$$\Braket{\psi |i\hbar\frac{\partial}{\partial t}|\phi}$$ 
\end{document}

I'd like to do the same thing with other delimiters, for example to typeset conditional probabilities like $P(A=\frac12|B)$.

Edit to clarify the question I'm interested to cases where I don't know which size of the |-sign is the biggest. An example could be $P(A=\frac12|B=2^{2^2})$.

share|improve this question
2  
Remember to never use $$ in LaTeX documents. –  egreg Nov 27 '11 at 21:01
    
Why ? Because it is more difficult to balance than '[]' ? The latter involve 6-times more keystrokes on my (French) keyboard, so I'm wondering whether the reason is really compelling ? –  Frédéric Grosshans Nov 28 '11 at 10:25
1  
add comment

1 Answer 1

up vote 12 down vote accepted

Use \middle|

$P\left( A = \frac{1}{2} \middle| B \right)$
share|improve this answer
4  
One should note that \middle| doesn't add space around the bar and so \;\middle|\; should be used. Even better, \nonscript\;\middle|\nonscript\; if this is used in a macro for something that can go into subscripts or superscripts. –  egreg Nov 27 '11 at 20:21
    
@egreg: I usually use \,\middle\, in macros, but \; is better. –  Aditya Nov 27 '11 at 20:38
    
isn't \middle e-tex specific ? If yes wouldn't that h-complicate the exchanges of documents with colleagues ? –  Frédéric Grosshans Nov 28 '11 at 10:35
1  
@FrédéricGrosshans Only very old distributions don't use by default an e-TeX enabled engine for LaTeX –  egreg Nov 28 '11 at 10:41
1  
OK. Then I'll try this and come back when I encounter an overconservative colleague :-) Thanks. –  Frédéric Grosshans Nov 28 '11 at 10:50
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.