English
There is a lemma stating that the liftHom constructed in the well-order induction data behaves compatibly with the maps F.map and the attaching cocone maps at succ steps.
Русский
Существует лемма, утверждающая, что построенное liftHom в рамках индукции по порядку согласуется с отображениями F.map и кокон-стрелами на шагах succ.
LaTeX
$$$$ \text{liftHom_fac}: F.map( homOfLE-hi ) \circ liftHom = (s.1) .f' $$$$
Lean4
/-- The projective system `sqFunctor c p f g` has a `WellOrderInductionData` structure. -/
noncomputable def wellOrderInductionData : (sqFunctor c p f g).WellOrderInductionData
where
succ j hj
sq' :=
have := hF j hj sq'.f'
have := hF j hj
{ f' := sq'.sq.lift
w₁ := by
dsimp
simp only [← sq'.w₁]
conv_rhs => rw [← sq'.sq.fac_left, ← F.map_comp_assoc]
rfl }
map_succ j hj sq' := by cat_disch
lift j hj s := lift hj s
map_lift j hj s i hij := map_lift hj s hij