% There are three ways of getting the latest versions of the macros:
% 1. capture the latest versions.
% 2. Make the changes suggested below
% 3. \input this file AFTER you have \input mtex.tex and diagram.tex
%
%
% The following should be put into mtex.tex instead of the definition of
% the \blist that is already there:
%
\makeatletter
\def\bl@st#1[#2]{\begin{labeledlist}{#1}\setcounter{lister}{#2}}
\def\blist#1{\@ifnextchar [{\bl@st{#1}}{\bl@st{#1}[0]}}
\makeatother
% The definition of \tofro in mtex.tex should be removed and the
% definition in diagram.tex should be replaced by the following:
\def\tofr@^#1_#2{\def\n@one{#1}\def\n@two{#2}\mathrel{\setw@dth{#1}{#2}
\mathop{\vcenter{\hbox to \w@dth{\rightarrowfill}\kern-1.7ex
\hbox to \w@dth{\leftarrowfill}}%
}\limits
\ifx\n@one\empty\else ^{\box\z@}\fi
\ifx\n@two\empty\else _{\box\@ne}\fi}}
\def\t@fr@^#1{\@ifnextchar_ {\tofr@^{#1}}{\tofr@^{#1}_{}}}
\def\tofro{\@ifnextchar^ {\t@fr@}{\t@fr@^{}}}
% The only change is in the third line where \rightarrow has been
% replaced by \leftarrow.