A

David

Darling

homology

Homology is a way of attaching Abelian groups, or more elaborate algebraic objects, to a topological space so as to obtain algebraic invariants. In a sense, it detects the presence of "holes" of various dimensions in the space. The methods developed to handle this led to what is now called homological algebra, a subject in which homological invariants are calculated for many purely algebraic structures.