English
If M1 and M2 are Noetherian submodules, then their supremum M1 ⊔ M2 is Noetherian.
Русский
Если подмодули M1 и M2 являются Noetherian, то их сумма M1 ⊔ M2 также Noetherian.
LaTeX
$$$[IsNoetherian R M_1] \wedge [IsNoetherian R M_2] \Rightarrow IsNoetherian R (M_1 \lor M_2)$$$
Lean4
instance isNoetherian_sup (M₁ M₂ : Submodule R P) [IsNoetherian R M₁] [IsNoetherian R M₂] : IsNoetherian R ↥(M₁ ⊔ M₂) :=
by
have := isNoetherian_range (M₁.subtype.coprod M₂.subtype)
rwa [LinearMap.range_coprod, Submodule.range_subtype, Submodule.range_subtype] at this