English
If Φ.IsLeftDerivabilityStructure, then ((Φ.catCommSq L₁ L₂).iso).inv gives a guitart exactness for the inverted direction.
Русский
Если Φ обладает левой деривируемостью, то соответствующий инверсный изоморфизм даёт точность Гитурата.
LaTeX
$$$[\Phi.IsLeftDerivabilityStructure] \Rightarrow TwoSquare.GuitartExact\big((\Phi.catCommSq L_1 L_2).iso\!\big).inv$$$
Lean4
/-- If a localizer morphism `Φ` is a localized equivalence, then it is a right
derivability structure if the categories of right resolutions are connected and the
categories of right resolutions of arrows are nonempty. -/
theorem mk' [Φ.IsLocalizedEquivalence] : Φ.IsRightDerivabilityStructure :=
by
rw [Φ.isRightDerivabilityStructure_iff (Φ.functor ⋙ W₂.Q) W₂.Q (𝟭 _) (Functor.rightUnitor _).symm,
TwoSquare.guitartExact_iff_isConnected_downwards]
intro X₂ X₃ g
apply Constructor.isConnected