Simplicial homotopy
# Simplicial homotopy

In algebraic topology, a simplicial $homotopy^{pg23}$ is an analog of a homotopy between topological spaces for simplicial sets. If

    $f,g:X\to Y$

are maps between simplicial sets, a simplicial homotopy from f to g is a map

    $h:X\times \Delta ^{1}\to Y$

such that the diagram (see ) formed by f, g and h commute; the key is to use the diagram that results in $f(x)=h(x,0)$ and $g(x)=h(x,1)$ for all x in X.

