In mathematics, an endomorphism's a morphism (or homomorphism) from a mathematical object to itself. For example, an endomorphism of a vector space V's a linear map ƒ: V → V, and an endomorphism of a group G's a group homomorphism ƒ: G → G. In general, we can talk about endomorphisms in any category. In the category of sets, endomorphisms are simply functions from a set S into itself. In any category, the composition of any two endomorphisms of X's again an endomorphism of… (More on Endomorphism)