English
There is a lemma expressing that the weight-space at weight χ x is nonzero when considering generalized eigenvectors.
Русский
Существует лемма, выражающая не равно нулю весовое пространство χ(x) для обобщённых собственных векторов.
LaTeX
$$genWeightSpaceOf M (χ x) x ≠ ⊥$$
Lean4
@[simp]
theorem genWeightSpace_zero_normalizer_eq_self : (genWeightSpace M (0 : L → R)).normalizer = genWeightSpace M 0 :=
by
refine le_antisymm ?_ (LieSubmodule.le_normalizer _)
intro m hm
rw [LieSubmodule.mem_normalizer] at hm
simp only [mem_genWeightSpace, Pi.zero_apply, zero_smul, sub_zero] at hm ⊢
intro y
obtain ⟨k, hk⟩ := hm y y
use k + 1
simpa [pow_succ, Module.End.mul_eq_comp]