math/tex-mathpartir - The NetBSD Packages Collection

The package provides macros for typesetting math formulas in
mixed horizontal and vertical mode, automatically as best fit.
It provides an environment mathpar that behaves much as a loose
centered paragraph where words are math formulas, and spaces
between them are larger and adjustable. It also provides a
macro \inferrule for typeseting fractions where both the
numerator and denominator may be sequences of formulas that
will be also typeset in a similar way. It can typically be used
for typeseting sets of type inference rules or typing
derivations. A macro inferrule for typesetting type inference
rules.