Kerodon

$\Newextarrow{\xRightarrow}{5,5}{0x21D2}$
$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$

Remark 4.2.1.11. Let $f: X_{} \rightarrow Y_{}$ and $g: Y_{} \rightarrow Z_{}$ be morphisms of simplicial sets. If both $f$ and $g$ are left fibrations, then the composite map $(g \circ f): X_{} \rightarrow Z_{}$ is a left fibration. If both $f$ and $g$ are right fibrations, then $g \circ f$ is a right fibration.