\isaindent;

--- a/lib/texinputs/isabelle.sty	Sat Jan 20 00:35:35 2001 +0100
+++ b/lib/texinputs/isabelle.sty	Sun Jan 21 13:21:14 2001 +0100
@@ -39,6 +39,7 @@
 
 \newcommand{\isa}[1]{\emph{\isastyleminor #1}}
 
+\newcommand{\isaindent}[1]{\hphantom{#1}}
 \newcommand{\isanewline}{\mbox{}\\\mbox{}}
 \newcommand{\isadigit}[1]{#1}