\input eplain

This gives \eqdefn{aa}
$$1+2,\eqsubdef{op}$$
and
$$1+3.\eqsubdef{pp}$$
And \eqref{aa} and \eqref{op} and \eqref{pp}.
\bye

From: deleeuw@laplace.sscnet.ucla.edu (Jan Deleeuw)
Subject: batch mode
To: karl@cs.umb.edu
Date: Mon, 7 Jun 1993 20:26:22 -0700 (PDT)