endomorphism ring
英[ˌendəuˈmɔ:fizm riŋ]美[ˌɛndəˈmɔrˌfɪzəm rɪŋ]
In abstract algebra, the endomorphism ring of an abelian group X, denoted by End(X), is the set of all homomorphisms of X into itself. The addition operation is defined by pointwise addition of functions and the multiplication operation is defined by function composition.