English
Under surjectivity hypotheses, the lcs_map_eq equality holds for the lower central series under Lie homomorphisms.
Русский
При условии сюръективности выполняется равенство лк-сопоставления нижних центральных серий под Ли-гомоморфизмами.
LaTeX
$$theorem lieModule_lcs_map_eq (k : ℕ) : (lowerCentralSeries R L M k : Submodule R M).map g = lowerCentralSeries R L₂ M₂ k$$
Lean4
theorem lieModuleIsNilpotent [IsNilpotent L M] : IsNilpotent L₂ M₂ :=
by
obtain ⟨k, hk⟩ := IsNilpotent.nilpotent R L M
rw [isNilpotent_iff R]
use k
rw [← LieSubmodule.toSubmodule_inj] at hk ⊢
simp [← hf_surj.lieModule_lcs_map_eq hfg hg_surj k, hk]