English
For G a Cofork on F, the inverse equivalence preserves the π component: ((reflexiveCoforkEquivCofork F).inverse.obj G).π = G.π.
Русский
Для кофокора G обратная эквивалентность сохраняет π: ((reflexiveCoforkEquivCofork F).inverse.obj G).π = G.π.
LaTeX
$$$((\mathrm{reflexiveCoforkEquivCofork} F).inverse.obj G).\pi = G.\pi$$$
Lean4
@[simp]
theorem reflexiveCoforkEquivCofork_inverse_obj_π (G : Cofork (F.map left) (F.map right)) :
((reflexiveCoforkEquivCofork F).inverse.obj G).π = G.π :=
by
dsimp only [reflexiveCoforkEquivCofork, Equivalence.symm, Equivalence.trans, ReflexiveCofork.π,
Cocones.precomposeEquivalence, Cocones.precompose, Functor.comp, Functor.Final.coconesEquiv]
rw [Functor.Final.extendCocone_obj_ι_app' (Y := .one) (f := 𝟙 zero)]
simp