Abstract simplicial complexes in {\tt Macaulay2}

{\tt AbstractSimplicialComplexes.m2} is a computer algebra package written for the computer algebra system {\tt Macaulay2} \cite{M2}. It provides new infrastructure to work with abstract simplicial complexes and related homological constructions. Its key novel feature is to implement each given abstract simplicial complex as a certain graded list in the form of a hash table with integer keys. Among other features, this allows for a direct implementation of the associated reduced and non-reduced simplicial chain complexes. Further, it facilitates construction of random simplicial complexes. The approach that we employ here builds on the {\tt Macaulay2} package {\tt Complexes.m2} \cite{Stillman:Smith:Complexes.m2}. It complements and is entirely different from the existing {\tt Macaulay2} simplicial complexes framework that is made possible by the package {\tt SimplicialComplexes.m2} \cite{Smith:et:al:SimplicialComplexes.m2:jsag}.