The Excision Theorem is a fundamental result in algebraic topology, particularly in the context of singular homology. It addresses how the homology groups of a topological space can be affected by the removal of a "nice" subspace.
Articles by others on the same topic
Excision identifies relative homology after removing a subspace whose closure lies in the interior of the subspace being quotiented. It makes local homology computable in an arbitrarily small neighborhood.