Kerodon

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

Corollary 3.5.9.25. Let $X$ be an $n$-truncated Kan complex, let $k$ be an integer, and let $j: A \rightarrow B$ be a $(k-1)$-connective morphism of simplicial sets. Then the induced map $\operatorname{Fun}(B,X) \rightarrow \operatorname{Fun}(A,X)$ is $(n-k)$-truncated.

Proof. Apply Proposition 3.5.9.24 in the special case $Y = \Delta ^0$ (see Example 3.5.9.4). $\square$