Normal epimorphism
A morphism having the characteristic property of the natural mapping of a group onto a quotient group or of a ring onto a quotient ring. Let be a category with zero morphisms. A morphism \nu : A \rightarrow V is called a normal epimorphism if every morphism \phi : A \rightarrow Y for which it always follows from \alpha.\nu = 0, \alpha : X \rightarrow A, that \alpha.\phi = 0, can be uniquely represented in the form \phi = \nu.\phi'. The cokernel of any morphism is a normal epimorphism. The converse assertion is false, in general; however, when morphisms in \mathfrak{K} have kernels, then every normal epimorphism is a cokernel. In an Abelian category every epimorphism is normal. The concept of a normal epimorphism is dual to that of a normal monomorphism.
Normal epimorphism. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Normal_epimorphism&oldid=34178