[texhax] \mid Description

[P. R. Stanley]

> > What does the \mid macro do in the below line, that's to say, what
> > visual effect does it, well, effect?
> > \[(a_1 \to P_1 \mid \ldots \mid a_n \to P_n) \]
>
>A vertical line like \vert or |, but with equal spacing on either side so
>that it looks better in the middle of an expression.
paul: A-ha! It makes sense since it is the guarded alternative symbol in CSP.

Thanks,
Paul