English
The continuous functional calculus produces a star-normal element: cfc f a is IsStarNormal for any f and a satisfying the setup.
Русский
Непрерывное функциональное вычисление даёт звездо-нормальный элемент: cfc f a нормален относительно оператора *.
LaTeX
$$IsStarNormal (cfc f a)$$
Lean4
@[simp]
instance cfc_map (f : R → R) (a : A) : IsStarNormal (cfc f a) where
star_comm_self := by
rw [Commute, SemiconjBy]
by_cases h : ContinuousOn f (spectrum R a)
· rw [← cfc_star, ← cfc_mul .., ← cfc_mul ..]
congr! 2
exact mul_comm _ _
·
simp [cfc_apply_of_not_continuousOn a h]
-- The following two lemmas are just `cfc_predicate`, but specific enough for the `@[simp]` tag.