View source for Homology base

''(of a complex or of a topological space) with respect to a given coefficient group''

A system of cycles <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/h/h047/h047770/h0477701.png" /> with the following properties: None of their non-trivial linear combinations is homologous to zero and each [[Cycle|cycle]] is homologous to one of their linear combinations.