epimorphism
Noun
Meaning
epimorphism (plural epimorphisms)
(category theory) A morphism p such that for any other pair of morphisms f and g, if
f
∘
p
=
g
∘
p
{\displaystyle f\circ p=g\circ p}
, then f = g.
Synonyms
Related terms
Examples
Any morphism with a right inverse is an epimorphism, but the converse is not true in general.
A morphism f:A → B of rings is a homological epimorphism if it is an epimorphism and it induces a full and faithfull functor on derived categories: D(f) : D(B) → D(A).
A similar argument shows that the natural ring homomorphism from any commutative ring R to any one of its localizations is an epimorphism.
A strong epimorphism satisfies a certain lifting property with respect to commutative squares involving a monomorphism.
A split epimorphism is a morphism which has a right-sided inverse.
As some of the above examples show, the property of being an epimorphism is not determined by the morphism alone, but also by the category of context.