[Tex/LaTex] Sane spacing after min max

math-operatorsspacing

The default definitions of \min and \max insert basically no space after them, which looks really awful when stating optimisation problems, etc., in display equations. I could not figure out any way automatically insert space after them? The following, for one, did not work:

\renewcommand{\min}{\expandafter\,\operatorname*{min}}

The space still came before min. Is there a way that still causes super- and subscripts to be parsed correctly?

Addition: What I basically want is

\min_u\, G(u) + F(Ku)

in a display equation, without having to enter \, manually. A more complete statement, giving a better idea of the type of expressions, would be

\min_{u \in X}\, G(u)+F(Ku) \quad\text{subject to}\quad Au=b.

You really want that extra space there, but it would be nice not have to enter it manually.

Best Answer

The default definition of \min is

\def\min{\mathop{\operator@font min}}

so it is an operator like \log and will get a thin space in \min x but not in \min(x)

Your redefinition

\renewcommand{\min}{\expandafter\,\operatorname*{min}}

is the same as

\renewcommand{\min}{\,\operatorname*{min}}

and puts an additional thin space before the operator. the only effect of the \expandafter is to expand \operatorname one step before executing \, so your definition is actually equivalent to

\renewcommand{\min}{\,\protect\operatorname_*{min}}

where _ denotes a space character as one level of expansion just reveals the \protect that makes it a robust command.