English
There is a linear equivalence between M modulo (r :: rs) and QuotSMulTop r applied to M modulo rs.
Русский
Существует линейное эквивалентное отображение между M/(r :: rs) и QuotSMulTop r (M/(rs)).
LaTeX
$$$\\left(M \\Big\\slash (\\text{Ideal.ofList } (r :: rs) \\;\\top)\\right) \\cong_{R} \\; \\text{QuotSMulTop } r \\left(M \\Big/ (\\text{Ideal.ofList rs } \\top)\\right)$$$
Lean4
/-- The equivalence between M ⧸ (r₀, r₁, …, rₙ)M and (M ⧸ r₀M) ⧸ (r₁, …, rₙ) (M ⧸ r₀M). -/
def quotOfListConsSMulTopEquivQuotSMulTopInner :
(M ⧸ (Ideal.ofList (r :: rs) • ⊤ : Submodule R M)) ≃ₗ[R]
QuotSMulTop r M ⧸ (Ideal.ofList rs • ⊤ : Submodule R (QuotSMulTop r M)) :=
quotEquivOfEq _ _ (Ideal.ofList_cons_smul r rs ⊤) ≪≫ₗ
(quotientQuotientEquivQuotientSup (r • ⊤) (Ideal.ofList rs • ⊤)).symm ≪≫ₗ
quotEquivOfEq _ _ (by rw [map_smul'', map_top, range_mkQ])