Nerve (category theory)
= Nerve
{disambiguate=category theory}
{title2=$N(\mathcal C)$}
{wiki}
= Nerve of a category
{synonym}
The nerve of a category $\mathcal C$ has
$$
N(\mathcal C)_n=\operatorname{Fun}([n],\mathcal C),
$$
so an $n$-simplex is a string of $n$ composable morphisms. Every inner horn in a nerve has a unique filler.