English
Let i, j ∈ Fin(m) and h with m ≤ n. Then the preimage of the open-closed interval Ico at castLE(h i) to castLE(h j) under castLE(h) equals Ico(i, j).
Русский
Пусть i, j ∈ Fin(m) и h с m ≤ n. Тогда предобраз интервала Ico(castLE(h,i), castLE(h,j)) по отображению castLE(h) равен Ico(i, j).
LaTeX
$$$castLE(h)^{-1}'\mathrm{Ico}(\mathrm{castLE}(h,i), \mathrm{castLE}(h,j)) = \mathrm{Ico}(i, j)$$$
Lean4
@[simp]
theorem preimage_castLE_Ico_castLE (i j : Fin m) (h : m ≤ n) : castLE h ⁻¹' Ico (castLE h i) (castLE h j) = Ico i j :=
rfl