ThmDex – An index of mathematical definitions, results, and conjectures.
F10724
Formulation 0
Let $f : X \to Y$ and $g : Y \to Z$ each be a D466: Surjective map such that
(i) $g \circ f : X \to Z$ is a D527: Composite map of $f$ with $g$
Then $g \circ f$ is a D466: Surjective map.