Theorem: IsLocalization.localization_localization_exists_of_eq
File: Mathlib/RingTheory/Localization/LocalizationLocalization.lean

Proof steps:
state_before: R : Type u_1
inst✝⁹ : CommSemiring R
M : Submonoid R
S : Type u_2
inst✝⁸ : CommSemiring S
inst✝⁷ : Algebra R S
P : Type u_3
inst✝⁶ : CommSemiring P
N : Submonoid S
T : Type u_4
inst✝⁵ : CommSemiring T
inst✝⁴ : Algebra R T
inst✝³ : Algebra S T
inst✝² : IsScalarTower R S T
inst✝¹ : IsLocalization M S
inst✝ : IsLocalization N T
x y : R
⊢ (algebraMap R T) x = (algebraMap R T) y → ∃ c, ↑c * x = ↑c * y
state_after: R : Type u_1
inst✝⁹ : CommSemiring R
M : Submonoid R
S : Type u_2
inst✝⁸ : CommSemiring S
inst✝⁷ : Algebra R S
P : Type u_3
inst✝⁶ : CommSemiring P
N : Submonoid S
T : Type u_4
inst✝⁵ : CommSemiring T
inst✝⁴ : Algebra R T
inst✝³ : Algebra S T
inst✝² : IsScalarTower R S T
inst✝¹ : IsLocalization M S
inst✝ : IsLocalization N T
x y : R
⊢ (∃ c, ↑c * (algebraMap R S) x = ↑c * (algebraMap R S) y) → ∃ c, ↑c * x = ↑c * y
tactic: rw [IsScalarTower.algebraMap_apply R S T, IsScalarTower.algebraMap_apply R S T,
    IsLocalization.eq_iff_exists N T]
state_before: R : Type u_1
inst✝⁹ : CommSemiring R
M : Submonoid R
S : Type u_2
inst✝⁸ : CommSemiring S
inst✝⁷ : Algebra R S
P : Type u_3
inst✝⁶ : CommSemiring P
N : Submonoid S
T : Type u_4
inst✝⁵ : CommSemiring T
inst✝⁴ : Algebra R T
inst✝³ : Algebra S T
inst✝² : IsScalarTower R S T
inst✝¹ : IsLocalization M S
inst✝ : IsLocalization N T
x y : R
⊢ (∃ c, ↑c * (algebraMap R S) x = ↑c * (algebraMap R S) y) → ∃ c, ↑c * x = ↑c * y
state_after: case intro
R : Type u_1
inst✝⁹ : CommSemiring R
M : Submonoid R
S : Type u_2
inst✝⁸ : CommSemiring S
inst✝⁷ : Algebra R S
P : Type u_3
inst✝⁶ : CommSemiring P
N : Submonoid S
T : Type u_4
inst✝⁵ : CommSemiring T
inst✝⁴ : Algebra R T
inst✝³ : Algebra S T
inst✝² : IsScalarTower R S T
inst✝¹ : IsLocalization M S
inst✝ : IsLocalization N T
x y : R
z : ↥N
eq₁ : ↑z * (algebraMap R S) x = ↑z * (algebraMap R S) y
⊢ ∃ c, ↑c * x = ↑c * y
tactic: rintro ⟨z, eq₁⟩
state_before: case intro
R : Type u_1
inst✝⁹ : CommSemiring R
M : Submonoid R
S : Type u_2
inst✝⁸ : CommSemiring S
inst✝⁷ : Algebra R S
P : Type u_3
inst✝⁶ : CommSemiring P
N : Submonoid S
T : Type u_4
inst✝⁵ : CommSemiring T
inst✝⁴ : Algebra R T
inst✝³ : Algebra S T
inst✝² : IsScalarTower R S T
inst✝¹ : IsLocalization M S
inst✝ : IsLocalization N T
x y : R
z : ↥N
eq₁ : ↑z * (algebraMap R S) x = ↑z * (algebraMap R S) y
⊢ ∃ c, ↑c * x = ↑c * y
state_after: case intro.intro.mk
R : Type u_1
inst✝⁹ : CommSemiring R
M : Submonoid R
S : Type u_2
inst✝⁸ : CommSemiring S
inst✝⁷ : Algebra R S
P : Type u_3
inst✝⁶ : CommSemiring P
N : Submonoid S
T : Type u_4
inst✝⁵ : CommSemiring T
inst✝⁴ : Algebra R T
inst✝³ : Algebra S T
inst✝² : IsScalarTower R S T
inst✝¹ : IsLocalization M S
inst✝ : IsLocalization N T
x y : R
z : ↥N
eq₁ : ↑z * (algebraMap R S) x = ↑z * (algebraMap R S) y
z' : R
s : ↥M
eq₂ : ↑z * (algebraMap R S) ↑(z', s).2 = (algebraMap R S) (z', s).1
⊢ ∃ c, ↑c * x = ↑c * y
tactic: rcases IsLocalization.surj M (z : S) with ⟨⟨z', s⟩, eq₂⟩
state_before: case intro.intro.mk
R : Type u_1
inst✝⁹ : CommSemiring R
M : Submonoid R
S : Type u_2
inst✝⁸ : CommSemiring S
inst✝⁷ : Algebra R S
P : Type u_3
inst✝⁶ : CommSemiring P
N : Submonoid S
T : Type u_4
inst✝⁵ : CommSemiring T
inst✝⁴ : Algebra R T
inst✝³ : Algebra S T
inst✝² : IsScalarTower R S T
inst✝¹ : IsLocalization M S
inst✝ : IsLocalization N T
x y : R
z : ↥N
eq₁ : ↑z * (algebraMap R S) x = ↑z * (algebraMap R S) y
z' : R
s : ↥M
eq₂ : ↑z * (algebraMap R S) ↑(z', s).2 = (algebraMap R S) (z', s).1
⊢ ∃ c, ↑c * x = ↑c * y
state_after: case intro.intro.mk
R : Type u_1
inst✝⁹ : CommSemiring R
M : Submonoid R
S : Type u_2
inst✝⁸ : CommSemiring S
inst✝⁷ : Algebra R S
P : Type u_3
inst✝⁶ : CommSemiring P
N : Submonoid S
T : Type u_4
inst✝⁵ : CommSemiring T
inst✝⁴ : Algebra R T
inst✝³ : Algebra S T
inst✝² : IsScalarTower R S T
inst✝¹ : IsLocalization M S
inst✝ : IsLocalization N T
x y : R
z : ↥N
eq₁ : ↑z * (algebraMap R S) x = ↑z * (algebraMap R S) y
z' : R
s : ↥M
eq₂ : ↑z * (algebraMap R S) ↑s = (algebraMap R S) z'
⊢ ∃ c, ↑c * x = ↑c * y
tactic: dsimp only at eq₂
state_before: case intro.intro.mk
R : Type u_1
inst✝⁹ : CommSemiring R
M : Submonoid R
S : Type u_2
inst✝⁸ : CommSemiring S
inst✝⁷ : Algebra R S
P : Type u_3
inst✝⁶ : CommSemiring P
N : Submonoid S
T : Type u_4
inst✝⁵ : CommSemiring T
inst✝⁴ : Algebra R T
inst✝³ : Algebra S T
inst✝² : IsScalarTower R S T
inst✝¹ : IsLocalization M S
inst✝ : IsLocalization N T
x y : R
z : ↥N
eq₁ : ↑z * (algebraMap R S) x = ↑z * (algebraMap R S) y
z' : R
s : ↥M
eq₂ : ↑z * (algebraMap R S) ↑s = (algebraMap R S) z'
⊢ (algebraMap R S) (x * z') = (algebraMap R S) (y * z')
state_after: no goals
tactic: rw [map_mul, map_mul, ← eq₂, ← mul_assoc, ← mul_assoc, mul_comm _ (z : S), eq₁,
    mul_comm _ (z : S)]