Exercise 4.5.9.9. Let $\operatorname{\mathcal{B}}= \Delta ^2$ be the standard $2$-simplex and let $\operatorname{\mathcal{C}}= \operatorname{N}_{\bullet }( \{ 0 < 2 \} )$ be the long edge of $\operatorname{\mathcal{C}}$. Show that $\operatorname{Fun}( \operatorname{\mathcal{C}}/\operatorname{\mathcal{B}}, \Delta ^1 )$ is not an $\infty $-category.
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