Author: John Stembridge (jrs@math.lsa.umich.edu), Department of Mathematics, University of Michigan, Ann Arbor, MI 48109-1003
Posets is a package of ~32 Maple programs that provide an environment for computations involving partially ordered sets and related structures. The package is particularly useful for visualization of posets and for computing various poset invariants, such as Möbius functions. Also included is a library containing all 19,449 posets with less than 8 vertices and all 7,372 lattices with less than 10 vertices---this is convenient for investigating questions of the form ``Which posets in class X satisfy property Y?''.
At a minimum, you will need Maple V (Release 1 or later). In Release 1, the procedure for plotting posets is disabled, since it uses graphics features that were added in Maple V Release 2.