English
Lifting commutes with finite products: lift(prod c) = prod (i ↦ lift(c i)).
Русский
Подъём коммутирует с конечными произведениями: lift(prod c) = prod (i ↦ lift(c i)).
LaTeX
$$$ \operatorname{lift}(\operatorname{prod} c) = \operatorname{prod} (\lambda i. \operatorname{lift}(c(i))) $$$
Lean4
@[simp]
theorem lift_prod {ι : Type u} (c : ι → Cardinal.{v}) : lift.{w} (prod c) = prod fun i => lift.{w} (c i) :=
by
lift c to ι → Type v using fun _ => trivial
simp only [← mk_pi, ← mk_uLift]
exact mk_congr (Equiv.ulift.trans <| Equiv.piCongrRight fun i => Equiv.ulift.symm)