English
Applying the Dyson e-transform twice with the same parameter e yields the same result as applying it once: mulDysonETransform e (mulDysonETransform e x) = mulDysonETransform e x.
Русский
Повторное применение преобразования Дайсона с тем же параметром e дает тот же результат, что и первое применение: ...
LaTeX
$$mulDysonETransform e (mulDysonETransform e x) = mulDysonETransform e x$$
Lean4
@[to_additive (attr := simp)]
theorem mulDysonETransform_idem : mulDysonETransform e (mulDysonETransform e x) = mulDysonETransform e x :=
by
ext : 1 <;> dsimp
· rw [smul_finset_inter, smul_inv_smul, inter_comm, union_eq_left]
exact inter_subset_union
· rw [smul_finset_union, inv_smul_smul, union_comm, inter_eq_left]
exact inter_subset_union