# Kerodon

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

Definition 4.5.7.1. Let $q: X \rightarrow S$ be a morphism of simplicial sets. We will say that $q$ is an isofibration if it satisfies the following condition:

$(\ast )$

Let $B$ be a simplicial set and let $A \subseteq B$ be a simplicial subset for which the inclusion $A \hookrightarrow B$ is a categorical equivalence. Then every lifting problem

$\xymatrix@R =50pt@C=50pt{ A \ar [d] \ar [r] & X \ar [d]^{q} \\ B \ar [r] \ar@ {-->}[ur] & S }$