Module: Mathlib.RingTheory.Spectrum.Prime.ChevalleyComplexity

Goal state before:
pp: case refine_2
R : Type u_2
inst✝ : CommRing R
m n : ℕ
f : MvPolynomial (Fin n) R →ₐ[R] MvPolynomial (Fin m) R
k : ℕ
d : Multiset (Fin m)
S : ConstructibleSetData (MvPolynomial (Fin m) R)
hSn : ∀ C ∈ S, C.n ≤ k
hS : ∀ C ∈ S, ∀ (j : Fin C.n), (C.g j).degrees ≤ d
hf : ∀ (i : Fin n), (f (MvPolynomial.X i)).degrees ≤ d
g : MvPolynomial (Fin m) (MvPolynomial (Fin n) R) →+* MvPolynomial (Fin m) R := eval₂Hom f.toRingHom MvPolynomial.X
hg : g.comp (algebraMap (MvPolynomial (Fin n) R) (MvPolynomial (Fin m) (MvPolynomial (Fin n) R))) = ↑f
σ : MvPolynomial (Fin m) R →+* MvPolynomial (Fin m) (MvPolynomial (Fin n) R) :=
  MvPolynomial.map (algebraMap R (MvPolynomial (Fin n) R))
hσ : g.comp σ = RingHom.id (MvPolynomial (Fin m) R)
hσ' : ∀ (x : MvPolynomial (Fin m) R), g (σ x) = x
hg' : Surjective ⇑g
S' : ConstructibleSetData (MvPolynomial (Fin m) (MvPolynomial (Fin n) R)) :=
  Finset.image
    (fun x ↦
      match x with
      | { f := fk, n := k, g := gk } =>
        { f := σ fk, n := k + n,
          g := fun s ↦
            Sum.elim (⇑σ ∘ gk) (fun i ↦ MvPolynomial.C (MvPolynomial.X i) - σ (f (MvPolynomial.X i)))
              (finSumFinEquiv.symm s) })
    S
s₀ : Set (MvPolynomial (Fin m) (MvPolynomial (Fin n) R)) :=
  Set.range fun i ↦ MvPolynomial.C (MvPolynomial.X i) - σ (f (MvPolynomial.X i))
hs : zeroLocus s₀ = Set.range (comap g)
hg'' : ∀ (t : Set (PrimeSpectrum (MvPolynomial (Fin m) R))), comap g '' t = comap σ ⁻¹' t ∩ zeroLocus s₀
hS' : comap g '' S.toSet = S'.toSet
T : ConstructibleSetData (MvPolynomial (Fin n) R)
hT : comap MvPolynomial.C '' S'.toSet = T.toSet
hT' :
  ∀ C ∈ T,
    C.n ≤ MvPolynomialC.numBound (k + n) (fun i ↦ 1 + Multiset.count i (Multiset.map Fin.val d)) m ∧
      ∀ (i : Fin C.n),
        C.g i ∈
          Submodule.restrictScalars ℤ (degreesLE R (Fin n) Finset.univ.val) ^
            MvPolynomialC.degBound (k + n) (fun i ↦ 1 + Multiset.count i (Multiset.map Fin.val d)) m
C : BasicConstructibleSetData (MvPolynomial (Fin n) R)
hCT : C ∈ T
i : Fin C.n
j : Fin n
this :
  C.g i ∈
    Submodule.restrictScalars ℤ (degreesLE R (Fin n) Finset.univ.val) ^
      MvPolynomialC.degBound (k + n) (fun i ↦ 1 + Multiset.count i (Multiset.map Fin.val d)) m
⊢ degreeOf j (C.g i) ≤ degBound k m n d

Tactic:
rw [← Submodule.restrictScalars_pow (MvPolynomialC.degBound_pos ..).ne', ← degreesLE_nsmul,
      Submodule.restrictScalars_mem, mem_degreesLE,
        Multiset.le_iff_count] at this

Goal state after:
case refine_2
R : Type u_2
inst✝ : CommRing R
m n : ℕ
f : MvPolynomial (Fin n) R →ₐ[R] MvPolynomial (Fin m) R
k : ℕ
d : Multiset (Fin m)
S : ConstructibleSetData (MvPolynomial (Fin m) R)
hSn : ∀ C ∈ S, C.n ≤ k
hS : ∀ C ∈ S, ∀ (j : Fin C.n), (C.g j).degrees ≤ d
hf : ∀ (i : Fin n), (f (MvPolynomial.X i)).degrees ≤ d
g : MvPolynomial (Fin m) (MvPolynomial (Fin n) R) →+* MvPolynomial (Fin m) R := eval₂Hom f.toRingHom MvPolynomial.X
hg : g.comp (algebraMap (MvPolynomial (Fin n) R) (MvPolynomial (Fin m) (MvPolynomial (Fin n) R))) = ↑f
σ : MvPolynomial (Fin m) R →+* MvPolynomial (Fin m) (MvPolynomial (Fin n) R) :=
  MvPolynomial.map (algebraMap R (MvPolynomial (Fin n) R))
hσ : g.comp σ = RingHom.id (MvPolynomial (Fin m) R)
hσ' : ∀ (x : MvPolynomial (Fin m) R), g (σ x) = x
hg' : Surjective ⇑g
S' : ConstructibleSetData (MvPolynomial (Fin m) (MvPolynomial (Fin n) R)) :=
  Finset.image
    (fun x ↦
      match x with
      | { f := fk, n := k, g := gk } =>
        { f := σ fk, n := k + n,
          g := fun s ↦
            Sum.elim (⇑σ ∘ gk) (fun i ↦ MvPolynomial.C (MvPolynomial.X i) - σ (f (MvPolynomial.X i)))
              (finSumFinEquiv.symm s) })
    S
s₀ : Set (MvPolynomial (Fin m) (MvPolynomial (Fin n) R)) :=
  Set.range fun i ↦ MvPolynomial.C (MvPolynomial.X i) - σ (f (MvPolynomial.X i))
hs : zeroLocus s₀ = Set.range (comap g)
hg'' : ∀ (t : Set (PrimeSpectrum (MvPolynomial (Fin m) R))), comap g '' t = comap σ ⁻¹' t ∩ zeroLocus s₀
hS' : comap g '' S.toSet = S'.toSet
T : ConstructibleSetData (MvPolynomial (Fin n) R)
hT : comap MvPolynomial.C '' S'.toSet = T.toSet
hT' :
  ∀ C ∈ T,
    C.n ≤ MvPolynomialC.numBound (k + n) (fun i ↦ 1 + Multiset.count i (Multiset.map Fin.val d)) m ∧
      ∀ (i : Fin C.n),
        C.g i ∈
          Submodule.restrictScalars ℤ (degreesLE R (Fin n) Finset.univ.val) ^
            MvPolynomialC.degBound (k + n) (fun i ↦ 1 + Multiset.count i (Multiset.map Fin.val d)) m
C : BasicConstructibleSetData (MvPolynomial (Fin n) R)
hCT : C ∈ T
i : Fin C.n
j : Fin n
this :
  ∀ (a : Fin n),
    Multiset.count a (C.g i).degrees ≤
      Multiset.count a
        (MvPolynomialC.degBound (k + n) (fun i ↦ 1 + Multiset.count i (Multiset.map Fin.val d)) m • Finset.univ.val)
⊢ degreeOf j (C.g i) ≤ degBound k m n d