-\chardef\hat=`\^
-\catcode`\^=\active \def\activehat{{\tt \hat}} \let^ = \activehat
+\chardef\Hat=`\^
+\catcode`\^=\active \def\activehat{{\tt \Hat}} \let^ = \activehat
Thanks Ralph. I installed that change (with different names).
@math{\hat o} works for me now in the main text.
I see that something like
@chapter @math{\hat o}
still fails, because the catcode of \ is fixed as other when the
argument is read. Fixing that would be a big job, and I didn't try ... -k
