English
Equivalences of LiftStruct for a square in the opposite category and the corresponding square in the original category.
Русский
Эквиваленции LiftStruct для квадрата в противоположной категории и соответствующего квадрата в исходной.
LaTeX
$$$unopEquiv\ (sq) : LiftStruct\ sq \simeq LiftStruct\ sq.unop$$$
Lean4
/-- Equivalences of `LiftStruct` for a square in the opposite category and
the corresponding square in the original category. -/
def unopEquiv {A B X Y : Cᵒᵖ} {f : A ⟶ X} {i : A ⟶ B} {p : X ⟶ Y} {g : B ⟶ Y} (sq : CommSq f i p g) :
LiftStruct sq ≃ LiftStruct sq.unop where
toFun := unop
invFun := op
left_inv := by cat_disch
right_inv := by cat_disch