English
Equivalence between algebraMap membership and membership in the mapped ideal.
Русский
Эквивалентность между принадлежностью algebraMap и принадлежностью отображённому идеалу.
LaTeX
$$algebraMap_mem_map_algebraMap_iff I x$$
Lean4
theorem mk'_mem_map_algebraMap_iff (I : Ideal R) (x : R) (s : M) :
IsLocalization.mk' S x s ∈ I.map (algebraMap R S) ↔ ∃ s ∈ M, s * x ∈ I :=
by
rw [← Ideal.unit_mul_mem_iff_mem _ (IsLocalization.map_units S s), IsLocalization.mk'_spec',
IsLocalization.mem_map_algebraMap_iff M]
simp_rw [← map_mul, IsLocalization.eq_iff_exists M, mul_comm x, ← mul_assoc, ← Submonoid.coe_mul]
exact
⟨fun ⟨⟨y, t⟩, c, h⟩ ↦ ⟨_, (c * t).2, h ▸ I.mul_mem_left c.1 y.2⟩, fun ⟨s, hs, h⟩ ↦ ⟨⟨⟨_, h⟩, ⟨s, hs⟩⟩, 1, by simp⟩⟩