Remark 220.127.116.11. Suppose we are given a pullback diagram of simplicial sets
Let $e'$ be an edge of the simplicial set $X'$, having image $e = f(e')$ in $X$. If $e$ is $q$-cartesian, then $e'$ is $q'$-cartesian. Similarly, if $e$ is $q$-cocartesian, then $e'$ is $q'$-cocartesian.