English
Let N be a LieSubmodule of M and I a LieIdeal of L with h: I ≤ N.idealizer. Then the trace form on I,N equals the restriction of the trace form on L,M to I.
Русский
Пусть N — подмодуль Ли в M, I — Ли-идеал L и h: I ≤ N.idealizer. Тогда форма следа на паре I,N совпадает с ограничением формы следа на L,M к I.
LaTeX
$$$ traceForm\ R\ I\ N = (traceForm\ R\ L\ M).restrict I$$
Lean4
theorem traceForm_eq_of_le_idealizer : traceForm R I N = (traceForm R L M).restrict I :=
by
ext ⟨x, hx⟩ ⟨y, hy⟩
change _ = trace R M (φ x ∘ₗ φ y)
rw [N.trace_eq_trace_restrict_of_le_idealizer I h x hy]
rfl