-- Mathlib/FieldTheory/Minpoly/IsIntegrallyClosed.lean
theorem isIntegrallyClosed_dvd {s : S} (hs : IsIntegral R s) {p : R[X]}
    (hp : Polynomial.aeval s p = 0) : minpoly R s ∣ p

Proof state:
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : IsDomain R
inst✝³ : Algebra R S
inst✝² : IsDomain S
inst✝¹ : NoZeroSMulDivisors R S
inst✝ : IsIntegrallyClosed R
s : S
hs : IsIntegral R s
p : R[X]
hp : (Polynomial.aeval s) p = 0
K : Type u_1 := FractionRing R
⊢ minpoly R s ∣ p

Tactic:
let L := FractionRing S

Result:
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : IsDomain R
inst✝³ : Algebra R S
inst✝² : IsDomain S
inst✝¹ : NoZeroSMulDivisors R S
inst✝ : IsIntegrallyClosed R
s : S
hs : IsIntegral R s
p : R[X]
hp : (Polynomial.aeval s) p = 0
K : Type u_1 := FractionRing R
L : Type u_2 := FractionRing S
⊢ minpoly R s ∣ p

Proof state:
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : IsDomain R
inst✝³ : Algebra R S
inst✝² : IsDomain S
inst✝¹ : NoZeroSMulDivisors R S
inst✝ : IsIntegrallyClosed R
s : S
hs : IsIntegral R s
p : R[X]
hp : (Polynomial.aeval s) p = 0
K : Type u_1 := FractionRing R
L : Type u_2 := FractionRing S
⊢ minpoly R s ∣ p

Tactic:
let _ : Algebra K L := FractionRing.liftAlgebra R L

Result:
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : IsDomain R
inst✝³ : Algebra R S
inst✝² : IsDomain S
inst✝¹ : NoZeroSMulDivisors R S
inst✝ : IsIntegrallyClosed R
s : S
hs : IsIntegral R s
p : R[X]
hp : (Polynomial.aeval s) p = 0
K : Type u_1 := FractionRing R
L : Type u_2 := FractionRing S
x✝ : Algebra K L := FractionRing.liftAlgebra R L
⊢ minpoly R s ∣ p

Proof state:
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : IsDomain R
inst✝³ : Algebra R S
inst✝² : IsDomain S
inst✝¹ : NoZeroSMulDivisors R S
inst✝ : IsIntegrallyClosed R
s : S
hs : IsIntegral R s
p : R[X]
hp : (Polynomial.aeval s) p = 0
K : Type u_1 := FractionRing R
L : Type u_2 := FractionRing S
x✝ : Algebra K L := FractionRing.liftAlgebra R L
⊢ minpoly R s ∣ p

Tactic:
have := FractionRing.isScalarTower_liftAlgebra R L

Result:
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : IsDomain R
inst✝³ : Algebra R S
inst✝² : IsDomain S
inst✝¹ : NoZeroSMulDivisors R S
inst✝ : IsIntegrallyClosed R
s : S
hs : IsIntegral R s
p : R[X]
hp : (Polynomial.aeval s) p = 0
K : Type u_1 := FractionRing R
L : Type u_2 := FractionRing S
x✝ : Algebra K L := FractionRing.liftAlgebra R L
this : IsScalarTower R (FractionRing R) L
⊢ minpoly R s ∣ p

Proof state:
case refine_1.h
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : IsDomain R
inst✝³ : Algebra R S
inst✝² : IsDomain S
inst✝¹ : NoZeroSMulDivisors R S
inst✝ : IsIntegrallyClosed R
s : S
hs : IsIntegral R s
p : R[X]
hp : (Polynomial.aeval s) p = 0
K : Type u_1 := FractionRing R
L : Type u_2 := FractionRing S
x✝ : Algebra K L := FractionRing.liftAlgebra R L
this : IsScalarTower R (FractionRing R) L
⊢ (algebraMap K L).comp (algebraMap R K) = (algebraMap S L).comp (algebraMap R S)

Tactic:
rw [← IsScalarTower.algebraMap_eq, ← IsScalarTower.algebraMap_eq]

Result:
no goals

Proof state:
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : IsDomain R
inst✝³ : Algebra R S
inst✝² : IsDomain S
inst✝¹ : NoZeroSMulDivisors R S
inst✝ : IsIntegrallyClosed R
s : S
hs : IsIntegral R s
p : R[X]
hp : (Polynomial.aeval s) p = 0
K : Type u_1 := FractionRing R
L : Type u_2 := FractionRing S
x✝ : Algebra K L := FractionRing.liftAlgebra R L
this : IsScalarTower R (FractionRing R) L
⊢ minpoly K ((algebraMap S L) s) ∣ map (algebraMap R K) (p %ₘ minpoly R s)

Tactic:
rw [map_modByMonic _ (minpoly.monic hs), modByMonic_eq_sub_mul_div]

Result:
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : IsDomain R
inst✝³ : Algebra R S
inst✝² : IsDomain S
inst✝¹ : NoZeroSMulDivisors R S
inst✝ : IsIntegrallyClosed R
s : S
hs : IsIntegral R s
p : R[X]
hp : (Polynomial.aeval s) p = 0
K : Type u_1 := FractionRing R
L : Type u_2 := FractionRing S
x✝ : Algebra K L := FractionRing.liftAlgebra R L
this : IsScalarTower R (FractionRing R) L
⊢ minpoly K ((algebraMap S L) s) ∣
    map (algebraMap R K) p -
      map (algebraMap R K) (minpoly R s) * (map (algebraMap R K) p /ₘ map (algebraMap R K) (minpoly R s))

case _hq
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : IsDomain R
inst✝³ : Algebra R S
inst✝² : IsDomain S
inst✝¹ : NoZeroSMulDivisors R S
inst✝ : IsIntegrallyClosed R
s : S
hs : IsIntegral R s
p : R[X]
hp : (Polynomial.aeval s) p = 0
K : Type u_1 := FractionRing R
L : Type u_2 := FractionRing S
x✝ : Algebra K L := FractionRing.liftAlgebra R L
this : IsScalarTower R (FractionRing R) L
⊢ (map (algebraMap R K) (minpoly R s)).Monic

Proof state:
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : IsDomain R
inst✝³ : Algebra R S
inst✝² : IsDomain S
inst✝¹ : NoZeroSMulDivisors R S
inst✝ : IsIntegrallyClosed R
s : S
hs : IsIntegral R s
p : R[X]
hp : (Polynomial.aeval s) p = 0
⊢ minpoly R s ∣ p

Tactic:
let K := FractionRing R

Result:
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : IsDomain R
inst✝³ : Algebra R S
inst✝² : IsDomain S
inst✝¹ : NoZeroSMulDivisors R S
inst✝ : IsIntegrallyClosed R
s : S
hs : IsIntegral R s
p : R[X]
hp : (Polynomial.aeval s) p = 0
K : Type u_1 := FractionRing R
⊢ minpoly R s ∣ p

Proof state:
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : IsDomain R
inst✝³ : Algebra R S
inst✝² : IsDomain S
inst✝¹ : NoZeroSMulDivisors R S
inst✝ : IsIntegrallyClosed R
s : S
hs : IsIntegral R s
p : R[X]
hp : (Polynomial.aeval s) p = 0
K : Type u_1 := FractionRing R
L : Type u_2 := FractionRing S
x✝ : Algebra K L := FractionRing.liftAlgebra R L
this✝ : IsScalarTower R (FractionRing R) L
this : minpoly R s ∣ p %ₘ minpoly R s
⊢ p %ₘ minpoly R s = 0

Tactic:
exact Polynomial.eq_zero_of_dvd_of_degree_lt this (degree_modByMonic_lt p <| minpoly.monic hs)

Result:
no goals