Remark 7.2.1.2. Let $f: A \rightarrow B$ be a morphism of simplicial sets. Then $f$ is left cofinal if and only if the opposite morphism $f^{\operatorname{op}}: A^{\operatorname{op}} \rightarrow B^{\operatorname{op}}$ is right cofinal.
$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$