Theorem: KummerDedekind.Ideal.irreducible_map_of_irreducible_minpoly
File: Mathlib/NumberTheory/KummerDedekind.lean

Proof steps:
state_before: R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
x : S
I : Ideal R
inst✝³ : IsDomain R
inst✝² : IsIntegrallyClosed R
inst✝¹ : IsDedekindDomain S
inst✝ : NoZeroSMulDivisors R S
hI : I.IsMaximal
hI' : I ≠ ⊥
hx : comap (algebraMap R S) (conductor R x) ⊔ I = ⊤
hx' : _root_.IsIntegral R x
hf : Irreducible (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ Irreducible (Ideal.map (algebraMap R S) I)
state_after: R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
x : S
I : Ideal R
inst✝³ : IsDomain R
inst✝² : IsIntegrallyClosed R
inst✝¹ : IsDedekindDomain S
inst✝ : NoZeroSMulDivisors R S
hI : I.IsMaximal
hI' : I ≠ ⊥
hx : comap (algebraMap R S) (conductor R x) ⊔ I = ⊤
hx' : _root_.IsIntegral R x
hf : Irreducible (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
mem_norm_factors :
  normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) ∈
    normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ Irreducible (Ideal.map (algebraMap R S) I)
tactic: have mem_norm_factors : normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) ∈
      normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) := by
    simp [normalizedFactors_irreducible hf]
state_before: R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
x : S
I : Ideal R
inst✝³ : IsDomain R
inst✝² : IsIntegrallyClosed R
inst✝¹ : IsDedekindDomain S
inst✝ : NoZeroSMulDivisors R S
hI : I.IsMaximal
hI' : I ≠ ⊥
hx : comap (algebraMap R S) (conductor R x) ⊔ I = ⊤
hx' : _root_.IsIntegral R x
hf : Irreducible (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
mem_norm_factors :
  normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) ∈
    normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ Irreducible (Ideal.map (algebraMap R S) I)
state_after: R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
x : S
I : Ideal R
inst✝³ : IsDomain R
inst✝² : IsIntegrallyClosed R
inst✝¹ : IsDedekindDomain S
inst✝ : NoZeroSMulDivisors R S
hI : I.IsMaximal
hI' : I ≠ ⊥
hx : comap (algebraMap R S) (conductor R x) ⊔ I = ⊤
hx' : _root_.IsIntegral R x
hf : Irreducible (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
mem_norm_factors :
  normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) ∈
    normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ ∃ y, normalizedFactors (Ideal.map (algebraMap R S) I) = {y}
tactic: suffices ∃ y, normalizedFactors (I.map (algebraMap R S)) = {y} by
    obtain ⟨y, hy⟩ := this
    have h := normalizedFactors_prod (show I.map (algebraMap R S) ≠ 0 by
          rwa [← bot_eq_zero, Ne,
            map_eq_bot_iff_of_injective (NoZeroSMulDivisors.algebraMap_injective R S)])
    rw [associated_iff_eq, hy, Multiset.prod_singleton] at h
    rw [← h]
    exact
      irreducible_of_normalized_factor y
        (show y ∈ normalizedFactors (I.map (algebraMap R S)) by simp [hy])
state_before: R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
x : S
I : Ideal R
inst✝³ : IsDomain R
inst✝² : IsIntegrallyClosed R
inst✝¹ : IsDedekindDomain S
inst✝ : NoZeroSMulDivisors R S
hI : I.IsMaximal
hI' : I ≠ ⊥
hx : comap (algebraMap R S) (conductor R x) ⊔ I = ⊤
hx' : _root_.IsIntegral R x
hf : Irreducible (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
mem_norm_factors :
  normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) ∈
    normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ ∃ y, normalizedFactors (Ideal.map (algebraMap R S) I) = {y}
state_after: R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
x : S
I : Ideal R
inst✝³ : IsDomain R
inst✝² : IsIntegrallyClosed R
inst✝¹ : IsDedekindDomain S
inst✝ : NoZeroSMulDivisors R S
hI : I.IsMaximal
hI' : I ≠ ⊥
hx : comap (algebraMap R S) (conductor R x) ⊔ I = ⊤
hx' : _root_.IsIntegral R x
hf : Irreducible (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
mem_norm_factors :
  normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) ∈
    normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ ∃ y,
    Multiset.map (fun f => ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm f))
        (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach =
      {y}
tactic: rw [normalizedFactors_ideal_map_eq_normalizedFactors_min_poly_mk_map hI hI' hx hx']
state_before: R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
x : S
I : Ideal R
inst✝³ : IsDomain R
inst✝² : IsIntegrallyClosed R
inst✝¹ : IsDedekindDomain S
inst✝ : NoZeroSMulDivisors R S
hI : I.IsMaximal
hI' : I ≠ ⊥
hx : comap (algebraMap R S) (conductor R x) ⊔ I = ⊤
hx' : _root_.IsIntegral R x
hf : Irreducible (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
mem_norm_factors :
  normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) ∈
    normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ ∃ y,
    Multiset.map (fun f => ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm f))
        (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach =
      {y}
state_after: case h
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
x : S
I : Ideal R
inst✝³ : IsDomain R
inst✝² : IsIntegrallyClosed R
inst✝¹ : IsDedekindDomain S
inst✝ : NoZeroSMulDivisors R S
hI : I.IsMaximal
hI' : I ≠ ⊥
hx : comap (algebraMap R S) (conductor R x) ⊔ I = ⊤
hx' : _root_.IsIntegral R x
hf : Irreducible (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
mem_norm_factors :
  normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) ∈
    normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ Multiset.map (fun f => ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm f))
      (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach =
    {↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm
          ⟨normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)), mem_norm_factors⟩)}
tactic: use ((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm
        ⟨normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)), mem_norm_factors⟩ :
      Ideal S)
state_before: case h
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
x : S
I : Ideal R
inst✝³ : IsDomain R
inst✝² : IsIntegrallyClosed R
inst✝¹ : IsDedekindDomain S
inst✝ : NoZeroSMulDivisors R S
hI : I.IsMaximal
hI' : I ≠ ⊥
hx : comap (algebraMap R S) (conductor R x) ⊔ I = ⊤
hx' : _root_.IsIntegral R x
hf : Irreducible (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
mem_norm_factors :
  normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) ∈
    normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ Multiset.map (fun f => ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm f))
      (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach =
    {↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm
          ⟨normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)), mem_norm_factors⟩)}
state_after: case h
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
x : S
I : Ideal R
inst✝³ : IsDomain R
inst✝² : IsIntegrallyClosed R
inst✝¹ : IsDedekindDomain S
inst✝ : NoZeroSMulDivisors R S
hI : I.IsMaximal
hI' : I ≠ ⊥
hx : comap (algebraMap R S) (conductor R x) ⊔ I = ⊤
hx' : _root_.IsIntegral R x
hf : Irreducible (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
mem_norm_factors :
  normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) ∈
    normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ ∃ a,
    (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach = {a} ∧
      ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm a) =
        ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm
            ⟨normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)), mem_norm_factors⟩)
tactic: rw [Multiset.map_eq_singleton]
state_before: case h
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
x : S
I : Ideal R
inst✝³ : IsDomain R
inst✝² : IsIntegrallyClosed R
inst✝¹ : IsDedekindDomain S
inst✝ : NoZeroSMulDivisors R S
hI : I.IsMaximal
hI' : I ≠ ⊥
hx : comap (algebraMap R S) (conductor R x) ⊔ I = ⊤
hx' : _root_.IsIntegral R x
hf : Irreducible (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
mem_norm_factors :
  normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) ∈
    normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ ∃ a,
    (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach = {a} ∧
      ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm a) =
        ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm
            ⟨normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)), mem_norm_factors⟩)
state_after: case h
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
x : S
I : Ideal R
inst✝³ : IsDomain R
inst✝² : IsIntegrallyClosed R
inst✝¹ : IsDedekindDomain S
inst✝ : NoZeroSMulDivisors R S
hI : I.IsMaximal
hI' : I ≠ ⊥
hx : comap (algebraMap R S) (conductor R x) ⊔ I = ⊤
hx' : _root_.IsIntegral R x
hf : Irreducible (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
mem_norm_factors :
  normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) ∈
    normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach =
      {⟨normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)), mem_norm_factors⟩} ∧
    ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm
          ⟨normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)), mem_norm_factors⟩) =
      ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm
          ⟨normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)), mem_norm_factors⟩)
tactic: use ⟨normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)), mem_norm_factors⟩
state_before: case h
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
x : S
I : Ideal R
inst✝³ : IsDomain R
inst✝² : IsIntegrallyClosed R
inst✝¹ : IsDedekindDomain S
inst✝ : NoZeroSMulDivisors R S
hI : I.IsMaximal
hI' : I ≠ ⊥
hx : comap (algebraMap R S) (conductor R x) ⊔ I = ⊤
hx' : _root_.IsIntegral R x
hf : Irreducible (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
mem_norm_factors :
  normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) ∈
    normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach =
      {⟨normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)), mem_norm_factors⟩} ∧
    ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm
          ⟨normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)), mem_norm_factors⟩) =
      ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm
          ⟨normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)), mem_norm_factors⟩)
state_after: case h
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
x : S
I : Ideal R
inst✝³ : IsDomain R
inst✝² : IsIntegrallyClosed R
inst✝¹ : IsDedekindDomain S
inst✝ : NoZeroSMulDivisors R S
hI : I.IsMaximal
hI' : I ≠ ⊥
hx : comap (algebraMap R S) (conductor R x) ⊔ I = ⊤
hx' : _root_.IsIntegral R x
hf : Irreducible (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
mem_norm_factors :
  normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) ∈
    normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach =
    {⟨normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)), mem_norm_factors⟩}
tactic: refine ⟨?_, rfl⟩
state_before: case h
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
x : S
I : Ideal R
inst✝³ : IsDomain R
inst✝² : IsIntegrallyClosed R
inst✝¹ : IsDedekindDomain S
inst✝ : NoZeroSMulDivisors R S
hI : I.IsMaximal
hI' : I ≠ ⊥
hx : comap (algebraMap R S) (conductor R x) ⊔ I = ⊤
hx' : _root_.IsIntegral R x
hf : Irreducible (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
mem_norm_factors :
  normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) ∈
    normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach =
    {⟨normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)), mem_norm_factors⟩}
state_after: case h.a
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
x : S
I : Ideal R
inst✝³ : IsDomain R
inst✝² : IsIntegrallyClosed R
inst✝¹ : IsDedekindDomain S
inst✝ : NoZeroSMulDivisors R S
hI : I.IsMaximal
hI' : I ≠ ⊥
hx : comap (algebraMap R S) (conductor R x) ⊔ I = ⊤
hx' : _root_.IsIntegral R x
hf : Irreducible (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
mem_norm_factors :
  normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) ∈
    normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ Multiset.map (fun a => ↑a) (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach =
    Multiset.map (fun a => ↑a) {⟨normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)), mem_norm_factors⟩}
tactic: apply Multiset.map_injective Subtype.coe_injective
state_before: case h.a
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
x : S
I : Ideal R
inst✝³ : IsDomain R
inst✝² : IsIntegrallyClosed R
inst✝¹ : IsDedekindDomain S
inst✝ : NoZeroSMulDivisors R S
hI : I.IsMaximal
hI' : I ≠ ⊥
hx : comap (algebraMap R S) (conductor R x) ⊔ I = ⊤
hx' : _root_.IsIntegral R x
hf : Irreducible (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
mem_norm_factors :
  normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) ∈
    normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ Multiset.map (fun a => ↑a) (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach =
    Multiset.map (fun a => ↑a) {⟨normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)), mem_norm_factors⟩}
state_after: case h.a
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
x : S
I : Ideal R
inst✝³ : IsDomain R
inst✝² : IsIntegrallyClosed R
inst✝¹ : IsDedekindDomain S
inst✝ : NoZeroSMulDivisors R S
hI : I.IsMaximal
hI' : I ≠ ⊥
hx : comap (algebraMap R S) (conductor R x) ⊔ I = ⊤
hx' : _root_.IsIntegral R x
hf : Irreducible (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
mem_norm_factors :
  normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) ∈
    normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) =
    {normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))}
tactic: rw [Multiset.attach_map_val, Multiset.map_singleton, Subtype.coe_mk]
state_before: case h.a
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
x : S
I : Ideal R
inst✝³ : IsDomain R
inst✝² : IsIntegrallyClosed R
inst✝¹ : IsDedekindDomain S
inst✝ : NoZeroSMulDivisors R S
hI : I.IsMaximal
hI' : I ≠ ⊥
hx : comap (algebraMap R S) (conductor R x) ⊔ I = ⊤
hx' : _root_.IsIntegral R x
hf : Irreducible (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
mem_norm_factors :
  normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) ∈
    normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)) =
    {normalize (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))}
state_after: no goals
tactic: exact normalizedFactors_irreducible hf