Commit 2024-09-03 09:13 79c4b69e
View on Github →feat(Topology/CompHaus): sigma-comparison map (#15525)
This PR defines the map CompHausLike.sigmaComparison
associated to a presheaf X
on
CompHausLike P
, and a finite family S₁,...,Sₙ
of spaces in CompHausLike P
, where P
is
stable under taking finite disjoint unions.
The map sigmaComparison
is the canonical map X(S₁ ⊔ ... ⊔ Sₙ) ⟶ X(S₁) × ... × X(Sₙ)
induced by
the inclusion maps Sᵢ ⟶ S₁ ⊔ ... ⊔ Sₙ
, and it is an isomorphism when X
preserves finite
products.