nLab
diagonal of a bisimplicial set

Definition

(diagonal)

For X , a bisimplicial set, its diagonal is the simplicial set that is the precomposition with (Id,Id):Δ opΔ op×Δ op, i.e. the simplicial set with components.

d(X) n=X n,n.d(X)_n = X_{n,n} \,.

See also diagonal.

Revised on April 18, 2013 18:50:16 by Tim Porter (95.147.236.226)