I would like to create a macro that defines a display formula, and then redefine the same macro such that the redefinition includes the original display formula followed by another display formula.  Here is my attempt.<br>
<br>\def\foo{\startformula a = b \stopformula} \foo<br>\edef\foo{\foo \startformula c = d \stopformula} \foo<br><br>This fails, and I would appreciate help in getting this to work.<br><br>Thanks,<br><br>Troy Henderson<br>