# Kerodon

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Example 5.1.1.4. Let $\operatorname{\mathcal{C}}$ be an $\infty$-category, let $q: \operatorname{\mathcal{C}}\rightarrow \Delta ^0$ be the projection map, and let $e: X \rightarrow Y$ be a morphism in $\operatorname{\mathcal{C}}$. The following conditions are equivalent:

• The morphism $e$ is an isomorphism.

• The morphism $e$ is $q$-cartesian.

• The morphism $e$ is $q$-cocartesian.

This is a restatement of Theorem 4.4.2.6.