Definition 14.28.1. Let \mathcal{C} be a category having finite products. Let U and V be two cosimplicial objects of \mathcal{C}. Let a, b : U \to V be two morphisms of cosimplicial objects of \mathcal{C}.
We say a morphism
h : U \longrightarrow \mathop{\mathrm{Hom}}\nolimits (\Delta [1], V)such that a = e_0 \circ h and b = e_1 \circ h is a homotopy from a to b.
We say a and b are homotopic or are in the same homotopy class if there exists a sequence a = a_0, a_1, \ldots , a_ n = b of morphisms from U to V such that for each i = 1, \ldots , n there either exists a homotopy from a_ i to a_{i - 1} or there exists a homotopy from a_{i - 1} to a_ i.
Comments (0)