форматировать уравнения для groff или MathML (format equations for groff or MathML)
MathML mode limitations
MathML is designed on the assumption that it cannot know the
exact physical characteristics of the media and devices on which
it will be rendered. It does not support fine control of motions
and sizes to the same degree troff does. Thus:
• eqn parameters have no effect on the generated MathML.
• The special, up, down, fwd, and back operations cannot be
implemented, and yield a MathML '<merror>' message
instead.
• The vcenter keyword is silently ignored, as centering on
the math axis is the MathML default.
• Characters that eqn sets extra large in troff mode—notably
the integral sign—may appear too small and need to have
their '<mstyle>' wrappers adjusted by hand.
As in its troff mode, eqn in MathML mode leaves the .EQ and .EN
delimiters in place for displayed equations, but emits no
explicit delimiters around inline equations. They can, however,
be recognized as strings that begin with '<math>' and end with
'</math>' and do not cross line boundaries.
See section 'Bugs' below for translation limits specific to eqn.
