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From: ruberman@BINAH.CC.BRANDEIS.EDU
Newsgroups: comp.text.tex
Subject: restricting functions
Message-ID: <0094534E.BFA393A0@BINAH.CC.BRANDEIS.EDU>
Date: 6 Mar 91 20:17:04 GMT
Sender: usenet@news.cs.brandeis.edu
Reply-To: ruberman@BINAH.CC.BRANDEIS.EDU
Organization: Brandeis University
Lines: 15

I wonder if anyone has a TeX or LaTeX macro that will display (nicely) the
restriction of functions in a mathematical paper.  That is, the name of the
function (say `f') followed by a vertical line extending below the current line
with some subspace. I can do this in many ways, but none of them seem to look
right.  For example: $f_{|X}$  doesn't look right since the vertical line
doesn't extend high enough, and the X is lowered too much. The best I can come
up with is variations on the theme of: $f\lower.5ex\hbox{$|X$}$, which still
doesn't quite make it.  In the paper in question, this construction occurs
in places in subscripts, so a \mathchoice construction is presumably needed.

If anyone has a way of doing this which is in reasonable accordance with 
standard principles of mathematical typography, please let me know.
	Daniel Ruberman
	ruberman@binah.cc.brandeis.edu
	ruberman@brandeis.bitnet