I am attempting to use a symbol from a separate font for the centered asterisk (∗) math operator. The font in question only has the heightened (in many fonts) asterisk glyph (*), which I try to use for the centered variant by lowering it.
In math mode, the operator can be used both by * and \ast, who are defined in exactly the same way at lines 150 and 297 in fontmath.ltx.
\ast can be redefined with \renewcommand, but * seems to be another beast. Can it be changed into a macro, or in any other way change the baseline of the glyph?
\documentclass{minimal}
\DeclareSymbolFont{mymathoperators}{OT1}{phv}{m}{n}
\DeclareMathSymbol{\protoast}{\mathbin}{mymathoperators}{"2A}
\DeclareMathSymbol{*}{\mathbin}{mymathoperators}{"2A}
\renewcommand*{\ast}{\mathbin{\raisebox{-0.7ex}{\ensuremath{\protoast}}}}
\begin{document}
\( good \ast , bad * . \)
\end{document}
*is not a letter, it cannot be used directly in a control word; here, a control word is a backslash followed by one or more letters. What you need to do is to make*"active", to use some TeX jargon, and then to assign*a certain meaning, e.g., to make it equivalent to{\ast}. – Mico Feb 12 '18 at 11:28