# nLab Gamma-set

Let $\Gamma^{op}$ (see Segal's category) be the skeleton of the category of finite pointed sets. We write $\underline{n}$ for the finite pointed set with $n$ non-basepoint elements. Then a $\Gamma$-set is a functor $X\colon \Gamma^{op}\to Set$.

The topos $\Set^{\Gamma^{op}}$ of $\Gamma$-sets is the classifying topos for pointed objects (MO question). For more on this see also at classifying topos for the theory of objects.

Related $n$Lab entries include Gamma-space, Segal's category.

Created on November 5, 2016 at 10:56:15. See the history of this page for a list of all contributions to it.