Module: Mathlib.RingTheory.Polynomial.Eisenstein.Criterion

Goal state before:
pp: case neg
R : Type u_1
inst✝³ : CommRing R
inst✝² : IsDomain R
K : Type u_2
inst✝¹ : Field K
inst✝ : Algebra R K
q f : R[X]
p : ℕ
hq_irr : Irreducible (map (algebraMap R K) q)
hq_monic : q.Monic
hf_prim : f.IsPrimitive
hfd0 : 0 < f.natDegree
hfP : (algebraMap R K) f.leadingCoeff ≠ 0
hfmodP : map (algebraMap R K) f = C ((algebraMap R K) f.leadingCoeff) * map (algebraMap R K) q ^ p
g h : R[X]
h_eq : f = g * h
P : Ideal R := ker (algebraMap R K)
hfmodP2 : map (Ideal.Quotient.mk (P ^ 2)) (f %ₘ q) ≠ 0
m : ℕ
r : R[X]
hg : g = C g.leadingCoeff * q ^ m + r
hr : map (algebraMap R K) r = 0
hm0 : m = 0 → IsUnit g
n : ℕ
s : R[X]
hh : h = C h.leadingCoeff * q ^ n + s
hs : map (algebraMap R K) s = 0
hn0 : n = 0 → IsUnit h
hm : ¬m = 0
hn : ¬n = 0
⊢ C g.leadingCoeff * q ^ m * (C h.leadingCoeff * q ^ n) %ₘ q + r * (C h.leadingCoeff * q ^ n) %ₘ q +
        C g.leadingCoeff * q ^ m * s %ₘ q +
      r * s %ₘ q =
    r * s %ₘ q

Tactic:
iterate 3 rw [(modByMonic_eq_zero_iff_dvd hq_monic).mpr]

Goal state after:
case neg
R : Type u_1
inst✝³ : CommRing R
inst✝² : IsDomain R
K : Type u_2
inst✝¹ : Field K
inst✝ : Algebra R K
q f : R[X]
p : ℕ
hq_irr : Irreducible (map (algebraMap R K) q)
hq_monic : q.Monic
hf_prim : f.IsPrimitive
hfd0 : 0 < f.natDegree
hfP : (algebraMap R K) f.leadingCoeff ≠ 0
hfmodP : map (algebraMap R K) f = C ((algebraMap R K) f.leadingCoeff) * map (algebraMap R K) q ^ p
g h : R[X]
h_eq : f = g * h
P : Ideal R := ker (algebraMap R K)
hfmodP2 : map (Ideal.Quotient.mk (P ^ 2)) (f %ₘ q) ≠ 0
m : ℕ
r : R[X]
hg : g = C g.leadingCoeff * q ^ m + r
hr : map (algebraMap R K) r = 0
hm0 : m = 0 → IsUnit g
n : ℕ
s : R[X]
hh : h = C h.leadingCoeff * q ^ n + s
hs : map (algebraMap R K) s = 0
hn0 : n = 0 → IsUnit h
hm : ¬m = 0
hn : ¬n = 0
⊢ 0 + 0 + 0 + r * s %ₘ q = r * s %ₘ q

case neg
R : Type u_1
inst✝³ : CommRing R
inst✝² : IsDomain R
K : Type u_2
inst✝¹ : Field K
inst✝ : Algebra R K
q f : R[X]
p : ℕ
hq_irr : Irreducible (map (algebraMap R K) q)
hq_monic : q.Monic
hf_prim : f.IsPrimitive
hfd0 : 0 < f.natDegree
hfP : (algebraMap R K) f.leadingCoeff ≠ 0
hfmodP : map (algebraMap R K) f = C ((algebraMap R K) f.leadingCoeff) * map (algebraMap R K) q ^ p
g h : R[X]
h_eq : f = g * h
P : Ideal R := ker (algebraMap R K)
hfmodP2 : map (Ideal.Quotient.mk (P ^ 2)) (f %ₘ q) ≠ 0
m : ℕ
r : R[X]
hg : g = C g.leadingCoeff * q ^ m + r
hr : map (algebraMap R K) r = 0
hm0 : m = 0 → IsUnit g
n : ℕ
s : R[X]
hh : h = C h.leadingCoeff * q ^ n + s
hs : map (algebraMap R K) s = 0
hn0 : n = 0 → IsUnit h
hm : ¬m = 0
hn : ¬n = 0
⊢ q ∣ C g.leadingCoeff * q ^ m * s

case neg
R : Type u_1
inst✝³ : CommRing R
inst✝² : IsDomain R
K : Type u_2
inst✝¹ : Field K
inst✝ : Algebra R K
q f : R[X]
p : ℕ
hq_irr : Irreducible (map (algebraMap R K) q)
hq_monic : q.Monic
hf_prim : f.IsPrimitive
hfd0 : 0 < f.natDegree
hfP : (algebraMap R K) f.leadingCoeff ≠ 0
hfmodP : map (algebraMap R K) f = C ((algebraMap R K) f.leadingCoeff) * map (algebraMap R K) q ^ p
g h : R[X]
h_eq : f = g * h
P : Ideal R := ker (algebraMap R K)
hfmodP2 : map (Ideal.Quotient.mk (P ^ 2)) (f %ₘ q) ≠ 0
m : ℕ
r : R[X]
hg : g = C g.leadingCoeff * q ^ m + r
hr : map (algebraMap R K) r = 0
hm0 : m = 0 → IsUnit g
n : ℕ
s : R[X]
hh : h = C h.leadingCoeff * q ^ n + s
hs : map (algebraMap R K) s = 0
hn0 : n = 0 → IsUnit h
hm : ¬m = 0
hn : ¬n = 0
⊢ q ∣ r * (C h.leadingCoeff * q ^ n)

case neg
R : Type u_1
inst✝³ : CommRing R
inst✝² : IsDomain R
K : Type u_2
inst✝¹ : Field K
inst✝ : Algebra R K
q f : R[X]
p : ℕ
hq_irr : Irreducible (map (algebraMap R K) q)
hq_monic : q.Monic
hf_prim : f.IsPrimitive
hfd0 : 0 < f.natDegree
hfP : (algebraMap R K) f.leadingCoeff ≠ 0
hfmodP : map (algebraMap R K) f = C ((algebraMap R K) f.leadingCoeff) * map (algebraMap R K) q ^ p
g h : R[X]
h_eq : f = g * h
P : Ideal R := ker (algebraMap R K)
hfmodP2 : map (Ideal.Quotient.mk (P ^ 2)) (f %ₘ q) ≠ 0
m : ℕ
r : R[X]
hg : g = C g.leadingCoeff * q ^ m + r
hr : map (algebraMap R K) r = 0
hm0 : m = 0 → IsUnit g
n : ℕ
s : R[X]
hh : h = C h.leadingCoeff * q ^ n + s
hs : map (algebraMap R K) s = 0
hn0 : n = 0 → IsUnit h
hm : ¬m = 0
hn : ¬n = 0
⊢ q ∣ C g.leadingCoeff * q ^ m * (C h.leadingCoeff * q ^ n)