The polynom package implements macros for manipulating polynomials, for example it can typeset long polynomial divisions. The main test case and application is the polynomial ring in one variable with rational coefficients.
The current release of this package typesets mathematics with unicode input and using OpenType maths fonts. (There is little compatibility with older maths packages.) XeTeX support is well tested, though LuaTeX support less so.
The package can typeset using STIX fonts, the XITS development of those fonts, the Asana-Math fonts and the commercial Cambria Math fonts. There is no support yet for any extra alphabets in the Unicode ‘private use area'.
The package relies on recent versions of the fontspec package and the l3kernel and l3packages bundles.
This package is the principal package in the AMS-LaTeX distribution. It adapts for use in LaTeX most of the mathematical features found in AMS-TeX; it is a near-indispensable adjunct to serious mathematical typesetting in LaTeX.
When amsmath is loaded, AMS-LaTeX packages amsbsy (for bold symbols), amsopn (for operator names) and amstext (for text embdedded in mathematics) are also loaded.
Amsmath is part of the LaTeX required distribution; however, several contributed packages add still further to its appeal; examples are empheq, which provides functions for decorating and highlighting mathematics, and ntheorem, for specifying theorem (and similar) definitions.