Vertical composition of Guitart exact squares #
In this file, we show that the vertical composition of Guitart exact squares is Guitart exact.
Given w : TwoSquare T L R B
, one may obtain a 2-square TwoSquare T L' R' B
if we
provide natural transformations α : L ⟶ L'
and β : R' ⟶ R
.
Equations
- w.whiskerVertical α β = CategoryTheory.CategoryStruct.comp (CategoryTheory.whiskerLeft T β) (CategoryTheory.CategoryStruct.comp w (CategoryTheory.whiskerRight α B))
Instances For
A 2-square stays Guitart exact if we replace the left and right functors
by isomorphic functors. See also whiskerVertical_iff
.
A 2-square is Guitart exact iff it is so after replacing the left and right functors by isomorphic functors.
The vertical composition of 2-squares.
Equations
- One or more equations did not get rendered due to their size.
Instances For
The canonical isomorphism between
w.structuredArrowDownwards Y₁ ⋙ w'.structuredArrowDownwards (R₁.obj Y₁)
and
(w.vComp w').structuredArrowDownwards Y₁.
Equations
- One or more equations did not get rendered due to their size.
Instances For
The vertical composition of 2-squares. (Variant where we allow the replacement of the vertical compositions by isomorphic functors.)
Equations
- w.vComp' w' eL eR = (w.vComp w').whiskerVertical eL.hom eR.inv