Theorem: KummerDedekind.normalizedFactors_ideal_map_eq_normalizedFactors_min_poly_mk_map
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
⊢ normalizedFactors (Ideal.map (algebraMap R S) I) =
    Multiset.map (fun f => ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm f))
      (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach
state_after: case 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
J : Ideal S
⊢ Multiset.count J (normalizedFactors (Ideal.map (algebraMap R S) I)) =
    Multiset.count J
      (Multiset.map (fun f => ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm f))
        (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach)
tactic: ext J
state_before: case 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
J : Ideal S
⊢ Multiset.count J (normalizedFactors (Ideal.map (algebraMap R S) I)) =
    Multiset.count J
      (Multiset.map (fun f => ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm f))
        (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach)
state_after: case pos
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
J : Ideal S
hJ : J ∈ normalizedFactors (Ideal.map (algebraMap R S) I)
⊢ Multiset.count J (normalizedFactors (Ideal.map (algebraMap R S) I)) =
    Multiset.count J
      (Multiset.map (fun f => ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm f))
        (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach)

case neg
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
J : Ideal S
hJ : J ∉ normalizedFactors (Ideal.map (algebraMap R S) I)
⊢ Multiset.count J (normalizedFactors (Ideal.map (algebraMap R S) I)) =
    Multiset.count J
      (Multiset.map (fun f => ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm f))
        (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach)
tactic: by_cases hJ : J ∈ normalizedFactors (I.map (algebraMap R S))
state_before: case pos
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
J : Ideal S
hJ : J ∈ normalizedFactors (Ideal.map (algebraMap R S) I)
⊢ Multiset.count J (normalizedFactors (Ideal.map (algebraMap R S) I)) =
    Multiset.count J
      (Multiset.map (fun f => ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm f))
        (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach)

case neg
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
J : Ideal S
hJ : J ∉ normalizedFactors (Ideal.map (algebraMap R S) I)
⊢ Multiset.count J (normalizedFactors (Ideal.map (algebraMap R S) I)) =
    Multiset.count J
      (Multiset.map (fun f => ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm f))
        (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach)
state_after: case neg
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
J : Ideal S
hJ : J ∉ normalizedFactors (Ideal.map (algebraMap R S) I)
⊢ Multiset.count J (normalizedFactors (Ideal.map (algebraMap R S) I)) =
    Multiset.count J
      (Multiset.map (fun f => ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm f))
        (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach)

case pos
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
J : Ideal S
hJ : J ∈ normalizedFactors (Ideal.map (algebraMap R S) I)
⊢ Multiset.count J (normalizedFactors (Ideal.map (algebraMap R S) I)) =
    Multiset.count J
      (Multiset.map (fun f => ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm f))
        (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach)
tactic: swap
state_before: case pos
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
J : Ideal S
hJ : J ∈ normalizedFactors (Ideal.map (algebraMap R S) I)
⊢ Multiset.count J (normalizedFactors (Ideal.map (algebraMap R S) I)) =
    Multiset.count J
      (Multiset.map (fun f => ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm f))
        (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach)
state_after: case pos
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
J : Ideal S
hJ : J ∈ normalizedFactors (Ideal.map (algebraMap R S) I)
this :
  multiplicity J (Ideal.map (algebraMap R S) I) =
    multiplicity (↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx') ⟨J, hJ⟩))
      (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ Multiset.count J (normalizedFactors (Ideal.map (algebraMap R S) I)) =
    Multiset.count J
      (Multiset.map (fun f => ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm f))
        (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach)
tactic: have := multiplicity_factors_map_eq_multiplicity hI hI' hx hx' hJ
state_before: case pos
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
J : Ideal S
hJ : J ∈ normalizedFactors (Ideal.map (algebraMap R S) I)
this :
  multiplicity J (Ideal.map (algebraMap R S) I) =
    multiplicity (↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx') ⟨J, hJ⟩))
      (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ Multiset.count J (normalizedFactors (Ideal.map (algebraMap R S) I)) =
    Multiset.count J
      (Multiset.map (fun f => ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm f))
        (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach)
state_after: case pos
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
J : Ideal S
hJ : J ∈ normalizedFactors (Ideal.map (algebraMap R S) I)
this :
  Multiset.count J (normalizedFactors (Ideal.map (algebraMap R S) I)) =
    Multiset.count (↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx') ⟨J, hJ⟩))
      (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x)))
⊢ Multiset.count J (normalizedFactors (Ideal.map (algebraMap R S) I)) =
    Multiset.count J
      (Multiset.map (fun f => ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx').symm f))
        (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))).attach)

case pos.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
J : Ideal S
hJ : J ∈ normalizedFactors (Ideal.map (algebraMap R S) I)
this :
  ↑(Multiset.count J (normalizedFactors (Ideal.map (algebraMap R S) I))) =
    ↑(Multiset.count (normalize ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx') ⟨J, hJ⟩))
        (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))))
⊢ ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx') ⟨J, hJ⟩) ∈ normalizedFactors ?m.130449

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
J : Ideal S
hJ : J ∈ normalizedFactors (Ideal.map (algebraMap R S) I)
this :
  ↑(Multiset.count J (normalizedFactors (Ideal.map (algebraMap R S) I))) =
    ↑(Multiset.count (normalize ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx') ⟨J, hJ⟩))
        (normalizedFactors (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))))
⊢ (R ⧸ I)[X]

case pos.ha
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
J : Ideal S
hJ : J ∈ normalizedFactors (Ideal.map (algebraMap R S) I)
this :
  ↑(Multiset.count (normalize J) (normalizedFactors (Ideal.map (algebraMap R S) I))) =
    multiplicity (↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx') ⟨J, hJ⟩))
      (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ Irreducible ↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx') ⟨J, hJ⟩)

case pos.hb
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
J : Ideal S
hJ : J ∈ normalizedFactors (Ideal.map (algebraMap R S) I)
this :
  ↑(Multiset.count (normalize J) (normalizedFactors (Ideal.map (algebraMap R S) I))) =
    multiplicity (↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx') ⟨J, hJ⟩))
      (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ Polynomial.map (Ideal.Quotient.mk I) (minpoly R x) ≠ 0

case pos.ha
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
J : Ideal S
hJ : J ∈ normalizedFactors (Ideal.map (algebraMap R S) I)
this :
  multiplicity J (Ideal.map (algebraMap R S) I) =
    multiplicity (↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx') ⟨J, hJ⟩))
      (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ Irreducible J

case pos.hb
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
J : Ideal S
hJ : J ∈ normalizedFactors (Ideal.map (algebraMap R S) I)
this :
  multiplicity J (Ideal.map (algebraMap R S) I) =
    multiplicity (↑((normalizedFactorsMapEquivNormalizedFactorsMinPolyMk hI hI' hx hx') ⟨J, hJ⟩))
      (Polynomial.map (Ideal.Quotient.mk I) (minpoly R x))
⊢ Ideal.map (algebraMap R S) I ≠ 0
tactic: rw [multiplicity_eq_count_normalizedFactors, multiplicity_eq_count_normalizedFactors,
    UniqueFactorizationMonoid.normalize_normalized_factor _ hJ,
    UniqueFactorizationMonoid.normalize_normalized_factor, PartENat.natCast_inj] at this