# Kerodon

$\Newextarrow{\xRightarrow}{5,5}{0x21D2}$ $\newcommand\empty{}$

Remark 3.1.4.5. Let $f: X \rightarrow Y$ and $g: Y \rightarrow Z$ be morphisms of simplicial sets. Suppose that $g$ is a covering map. Then $f$ is a covering map if and only if $g \circ f$ is a covering map. In particular, the collection of covering maps is closed under composition.