Lars Hellström writes: > Would it break anything if the LaTeX core would say > > \ifx \protected\@undefined \def\protected{} \fi > > and \protected was used before each definition of a LICR command? probably not (well, probably yes :-) i have yet to see a single change that doesn't break something, but for most purposes that should be a clear no). However, that would be fairly in efficient way to use the eTeX feature, ie if eTeX would be unconditionally used one could run far more efficient code since a lot of that \ifx\protect\typeset@protect could go away (and an LICR command on top-level expansion could be reduced to just two tokens) however, as a compatible start that actually works with TeX one could simply go \ifx \protected\@undefined \def\protected{} \else \WARNING-This-may-loose-characters-if-you-are-not-careful-better-use-etex \fi \protected\def\@current@cmd@math.... and that should do the trick frank