English
If c ∈ isotypicComponents and S ≤ c with S simple, then c equals the isotypicComponent determined by S.
Русский
Если c принадлежит isotypicComponents и S ≤ c с S простым, то c равно изотипической компоненте, определяемой S.
LaTeX
$$$$ c \\in \\mathrm{isotypicComponents}(R,M) \\; \\wedge \\; S \\le c \\; (S \\text{ прост}) \\Rightarrow c = \\mathrm{isotypicComponent}(R,M,S). $$$$
Lean4
theorem eq_isotypicComponent_of_le {S c : Submodule R M} (hc : c ∈ isotypicComponents R M) [IsSimpleModule R S]
(le : S ≤ c) : c = isotypicComponent R M S :=
by
obtain ⟨S', _, rfl⟩ := hc
have ⟨e⟩ := isIsotypicOfType_submodule_iff.mp (.isotypicComponent R M S') _ le
exact e.symm.isotypicComponent_eq