One of the Eilenberg-Steenrod axioms. Let be a single point space. unless , in which case where are some groups. The are called the coefficients of the homology .
Dimension Axiom
See also
Eilenberg-Steenrod Axioms, HomologyExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Dimension Axiom." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/DimensionAxiom.html