Sets Module for sets of positive integers.
Array sets Module for sets and multi-sets of positive integers. Sets are stored as arrays.
Graphs Module for basic graph operations.
Multiprecision integers Module for basic arithmetic on multiprecision integers.
Multiprecision integers: a Fortran module (manual)
Polynomials Module for multivariate Laurent-polynomials with dynamic storage.
Polynomials (a little less dynamic)
Polynomials (standard, one variable)
Polynomials: a Fortran module Manual.
Software and data for producing the Ising partition function for C_n x C_n (Update 2007-06-15: new version)