Let denote a chain complex, a portion of which is shown below:

Let denotes the th homology group. Then two homology cycles are said to be homologous, if their difference is a boundary, i.e., if .

Let denote a chain complex, a portion of which is shown below:

Let denotes the th homology group. Then two homology cycles are said to be homologous, if their difference is a boundary, i.e., if .

*This entry contributed by Rasmus
Hedegaard*

Hedegaard, Rasmus. "Homologous." From *MathWorld*--A Wolfram Web Resource, created by Eric
W. Weisstein. https://mathworld.wolfram.com/Homologous.html