fact: Definition totalAssociativity {X:UU} {Y: ∏ (x:X), UU} (Z: ∏ (x:X) (y:Y x), UU) : (∑ (x:X) (y:Y x), Z x y) ≃ (∑ (p:∑ (x:X), Y x), Z (pr1 p) (pr2 p)).
imports: UniMath.Foundations.All UniMath.MoreFoundations.Tactics