I find it a bit surprising that ConTeXt gives 'missing } inserted' with:
\starttext\startformula \mathop=^{\rm def} \stopformula\stoptext (\mathop{=}^... is fine, though). The above formula is correct in Plain (Lua)TeX (in fact, it is copied from The TeX Book). Why does ConTeXt need braces? (Before you point it out: I know that I should use \stackrel…) Nicola ___________________________________________________________________________________ If your question is of interest to others as well, please add an entry to the Wiki! maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context webpage : http://www.pragma-ade.nl / http://tex.aanhet.net archive : http://foundry.supelec.fr/projects/contextrev/ wiki : http://contextgarden.net ___________________________________________________________________________________