Path: galaxy.trc.rwcp.or.jp!coconuts.jaist!wnoc-tyo-news!waseda.ac.jp!onono
From: onono@fuka.info.waseda.ac.jp (ONO Kouichi)
Newsgroups: comp.specification.z,fj.lang.misc
Subject: zed.sty and \empty as an empty set
Date: 09 Feb 1995 09:19:34 GMT
Organization: Fukazawa Laboratory, Department of Information and Computer
	Science, School of Science and Engineering, WASEDA University, Tokyo,
	Japan
Lines: 56
Distribution: world
Message-ID: <ONONO.95Feb9181934@shuni.fuka.info.waseda.ac.jp>
NNTP-Posting-Host: onono@shuni.fuka.info.waseda.ac.jp
Xref: galaxy.trc.rwcp.or.jp fj.lang.misc:1444
X-originally-archived-at: http://galaxy.rwcp.or.jp/text/cgi-bin/newsarticle2?ng=fj.lang.misc&nb=1444&hd=a
X-reformat-date: Mon, 18 Oct 2004 15:18:22 +0900
X-reformat-comment: Tabs were expanded into 4 column tabstops by the Galaxy's archiver. See http://katsu.watanabe.name/ancientfj/galaxy-format.html for more info.

I've used zed.sty which I got from
ftp.comlab.ox.ac.uk:/pub/Zforum/zed.sty.

I found that \empty was defined as an empty set in
zed.sty, but it is the primitive in plain-TeX. So it
causes error when I use other style files that use
\empty as an empty token list.

I believe \empty shall not be redefined. The control
\empty must be defined as an empty token list at any
time. Therefore we don't use \empty as an empty set, but
\emptyset.

And then the following patch is to be applied to zed.sty
and zguide.tex.

--- zed.sty.distThu Feb  9 14:16:52 1995
+++ zed.styThu Feb  9 16:25:28 1995
@@ -145,7 +145,7 @@
 \def \ldata     {\langle\!\langle}
 \def \rdata     {\rangle\!\rangle}
 \let \shows\vdash
-\@mc \empty"0\@fy3F
+\@mc \emptyset"0\@fy3F
 \let \rel\leftrightarrow
 \def \dom{\mathop{\rm dom}}
 \def \ran{\mathop{\rm ran}}
--- zguide.tex.distThu Feb  9 14:45:40 1995
+++ zguide.texThu Feb  9 14:48:17 1995
@@ -382,7 +382,7 @@
 symbols defined as part of the mathematical tool-kit. First come the
 symbols which are not defined as infix operators, etc.:
 \begin{symtab}
-        \empty & \verb/\empty/ \\
+        \emptyset & \verb/\emptyset/ \\
 \bigcup & \verb/\bigcup/ \\
 \bigcap & \verb/\bigcap/ \\
 \dom & \verb/\dom/ \\
@@ -569,13 +569,13 @@
 \begin{verbatim}
 \[
     \exists PhoneDB @ \\
-\t1     known = \empty
+\t1     known = \emptyset
 \]       
 \end{verbatim}
 \gives
 \[
     \exists PhoneDB @ \\
-\t1     known = \empty
+\t1     known = \emptyset
 \]       
 \end{demo}
 These commands generalize the standard \LaTeX\ commands with the same
--
ONO Kouichi
