What are the AMS packages (“amsmath”, etc.)?
There are two components to the AMS LaTeX packages: amsmath
(a collection of packages that implements multi-line displayed equations,
equation numbering, ellipsis dots, matrices, double accents, multi-line subscripts,
text strings in math environments, and other things) and the
AMS document classes (
amsproc, which are comparable to the three basic LaTeX
amsthm). These components work together to produce output in the
preferred AMS style. The AMS document classes incorporate
amsthm can also
be used independently with non-AMS document classes.
Early in 2016, maintenance of
amsmath was transferred to the LaTeX Project team;
responsibility for the document classes and
amsthm remains with the AMS.
The canonical versions of the two collections reside on CTAN in distinct areas.
These packages were derived from AMSTeX, a TeX macro package based on Plain TeX, originally written by Michael Spivak for the American Mathematical Society (AMS) from 1983 to 1985 and described in the book “The Joy of TeX”. AMSTeX provides many features for producing more professional-looking maths formulas with less burden on authors. It pays attention to the finer details of sizing and positioning that mathematical publishers care about. However, it lacked automatic numbering and cross-referencing, and when LaTeX increased in popularity, authors sought to submit papers to the AMS in LaTeX, so AMSLaTeX was developed.
The AMS no longer recommends the use of AMSTeX, and urges its authors to use the LaTeX classes and packages instead.