This file contains information and classes for the various kinds of styles used in TeX, such as:
textstyle: used for math that is displayed inline
scriptstyle: used for math displayed in a superscript or subscript
scriptscriptstyle: used for math displayed in the superscript or subscript of a superscript or subscript.
It provides a generic
class which holds information about a specific style.
It also provides instances of all the different kinds of styles possible, and provides functions to move between them and get information about them.