mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.Algebra.MvPolynomial.Degrees

Goal state before:
pp: case a
R : Type u
σ : Type u_1
inst✝ : CommSemiring R
p q : MvPolynomial σ R
i : σ
h : degreeOf i q < degreeOf i p
⊢ degreeOf i p ≤ degreeOf i (p + q)

Tactic:
nth_rw 2 [degreeOf_eq_sup]

Goal state after:
case a
R : Type u
σ : Type u_1
inst✝ : CommSemiring R
p q : MvPolynomial σ R
i : σ
h : degreeOf i q < degreeOf i p
⊢ degreeOf i p ≤ (p + q).support.sup fun m ↦ m i
Module: Mathlib.Algebra.MvPolynomial.Variables

Goal state before:
pp: R : Type u
S : Type v
σ : Type u_1
inst✝¹ : CommSemiring R
inst✝ : CommSemiring S
f₁ : R →+* S
g₁ g₂ : σ → S
p₁ : MvPolynomial σ R
h : ∀ i ∈ p₁.vars, i ∈ p₁.vars → g₁ i = g₂ i
⊢ (eval₂Hom f₁ g₁) (∑ v ∈ p₁.support, (monomial v) (coeff v p₁)) =
    (eval₂Hom f₁ g₂) (∑ v ∈ p₁.support, (monomial v) (coeff v p₁))

Tactic:
simp only [map_sum, eval₂Hom_monomial]

Goal state after:
R : Type u
S : Type v
σ : Type u_1
inst✝¹ : CommSemiring R
inst✝ : CommSemiring S
f₁ : R →+* S
g₁ g₂ : σ → S
p₁ : MvPolynomial σ R
h : ∀ i ∈ p₁.vars, i ∈ p₁.vars → g₁ i = g₂ i
⊢ (∑ x ∈ p₁.support, f₁ (coeff x p₁) * x.prod fun i k ↦ g₁ i ^ k) =
    ∑ x ∈ p₁.support, f₁ (coeff x p₁) * x.prod fun i k ↦ g₂ i ^ k
Module: Mathlib.Algebra.MvPolynomial.Degrees

Goal state before:
pp: R : Type u
σ : Type u_1
inst✝ : CommSemiring R
s t : Multiset σ
x : MvPolynomial σ R
hx : x ∈ degreesLE R σ (s + t)
i : σ →₀ ℕ
hi : toMultiset i ≤ s + t
⊢ (monomial i) (coeff i x) ∈ degreesLE R σ s * degreesLE R σ t

Tactic:
let a := (i.toMultiset - t).toFinsupp

Goal state after:
R : Type u
σ : Type u_1
inst✝ : CommSemiring R
s t : Multiset σ
x : MvPolynomial σ R
hx : x ∈ degreesLE R σ (s + t)
i : σ →₀ ℕ
hi : toMultiset i ≤ s + t
a : σ →₀ ℕ := Multiset.toFinsupp (toMultiset i - t)
⊢ (monomial i) (coeff i x) ∈ degreesLE R σ s * degreesLE R σ t
Module: Mathlib.Algebra.Polynomial.Degree.TrailingDegree

Goal state before:
pp: case pos
R : Type u
inst✝ : Semiring R
p : R[X]
hp : p = 0
⊢ p.natTrailingDegree ≤ p.natDegree

pp: case neg
R : Type u
inst✝ : Semiring R
p : R[X]
hp : ¬p = 0
⊢ p.natTrailingDegree ≤ p.natDegree

Tactic:
· rw [hp, natDegree_zero, natTrailingDegree_zero]

Goal state after:
case neg
R : Type u
inst✝ : Semiring R
p : R[X]
hp : ¬p = 0
⊢ p.natTrailingDegree ≤ p.natDegree
Module: Mathlib.Algebra.Polynomial.EraseLead

Goal state before:
pp: case neg
R : Type u_2
inst✝² : Ring R
inst✝¹ : NoZeroDivisors R
inst✝ : Nontrivial R
x : R
P : R[X]
hx : x ≠ 0
h : P.nextCoeff = 0
hp : ¬P = 0
he : P.eraseLead = 0
he₂ : ¬((X - C x) * P).eraseLead = 0
⊢ ((X - C x) * P).eraseLead.eraseLead = 0

Tactic:
suffices #((X - C x) * P).support ≤ 2 by
      rw [← card_support_eq_zero]
      linarith [eraseLead_support_card_lt he₂,
        eraseLead_support_card_lt (mul_ne_zero (X_sub_C_ne_zero x) hp)]

Goal state after:
case neg
R : Type u_2
inst✝² : Ring R
inst✝¹ : NoZeroDivisors R
inst✝ : Nontrivial R
x : R
P : R[X]
hx : x ≠ 0
h : P.nextCoeff = 0
hp : ¬P = 0
he : P.eraseLead = 0
he₂ : ¬((X - C x) * P).eraseLead = 0
⊢ #((X - C x) * P).support ≤ 2
Module: Mathlib.Algebra.Polynomial.EraseLead

Goal state before:
pp: R : Type u_2
inst✝² : Ring R
inst✝¹ : NoZeroDivisors R
inst✝ : Nontrivial R
x : R
P : R[X]
hx : x ≠ 0
hp : ¬P = 0
he : ¬P.eraseLead = 0
h₁ : ((X - C x) * P).natDegree = P.natDegree + 1
dP : ℕ
hdP : P.natDegree = dP + 2
h : P.coeff (dP + 1) = 0
⊢ (if dP + 2 + 1 = 0 then 0 else ((X - C x) * P).coeff (dP + 2)) ≠ 0

Tactic:
coeff_X_sub_C_mul

Goal state after:
R : Type u_2
inst✝² : Ring R
inst✝¹ : NoZeroDivisors R
inst✝ : Nontrivial R
x : R
P : R[X]
hx : x ≠ 0
hp : ¬P = 0
he : ¬P.eraseLead = 0
h₁ : ((X - C x) * P).natDegree = P.natDegree + 1
dP : ℕ
hdP : P.natDegree = dP + 2
h : P.coeff (dP + 1) = 0
⊢ (if dP + 2 + 1 = 0 then 0 else P.coeff (dP + 1) - x * P.coeff (dP + 1 + 1)) ≠ 0
Module: Mathlib.Algebra.MvPolynomial.Equiv

Goal state before:
pp: case monomial
σ : Type u_1
R : Type u_2
S : Type u_3
inst✝² : CommSemiring R
inst✝¹ : CommSemiring S
inst✝ : Unique σ
φ : R →+* S
a : σ → S
d : σ →₀ ℕ
r : R
⊢ Polynomial.eval₂ φ (a default) ((Polynomial.monomial (d default)) r) = eval₂ φ a ((monomial d) r)

Tactic:
simp only [Polynomial.eval₂_monomial, eval₂_monomial]

Goal state after:
case monomial
σ : Type u_1
R : Type u_2
S : Type u_3
inst✝² : CommSemiring R
inst✝¹ : CommSemiring S
inst✝ : Unique σ
φ : R →+* S
a : σ → S
d : σ →₀ ℕ
r : R
⊢ φ r * a default ^ d default = φ r * d.prod fun n e ↦ a n ^ e
Module: Mathlib.Algebra.MvPolynomial.Equiv

Goal state before:
pp: σ : Type u_1
R : Type u_2
S : Type u_3
inst✝² : CommSemiring R
inst✝¹ : CommSemiring S
inst✝ : Unique σ
f : R[X]
φ : R →+* S
a : σ → S
⊢ Polynomial.eval₂ φ (a default) ((uniqueAlgEquiv R σ) ((uniqueAlgEquiv R σ).symm f)) = Polynomial.eval₂ φ (a default) f

Tactic:
AlgEquiv.apply_symm_apply

Goal state after:
σ : Type u_1
R : Type u_2
S : Type u_3
inst✝² : CommSemiring R
inst✝¹ : CommSemiring S
inst✝ : Unique σ
f : R[X]
φ : R →+* S
a : σ → S
⊢ Polynomial.eval₂ φ (a default) f = Polynomial.eval₂ φ (a default) f
Module: Mathlib.Algebra.MvPolynomial.Equiv

Goal state before:
pp: R : Type u
S₁ : Type v
S₂ : Type w
inst✝ : CommSemiring R
r : R
⊢ ((mapDomainRingEquiv R sumFinsuppAddEquivProdFinsupp).trans curryRingEquiv)
      ((have __src := singleZeroRingHom;
        { toFun := ⇑(monomial 0), map_one' := ⋯, map_mul' := ⋯, map_zero' := ⋯, map_add' := ⋯ })
        r) =
    (have __src := singleZeroRingHom;
      { toFun := ⇑(monomial 0), map_one' := ⋯, map_mul' := ⋯, map_zero' := ⋯, map_add' := ⋯ })
      ((have __src := singleZeroRingHom;
        { toFun := ⇑(monomial 0), map_one' := ⋯, map_mul' := ⋯, map_zero' := ⋯, map_add' := ⋯ })
        r)

Tactic:
simp [monomial]

Goal state after:
Module: Mathlib.Algebra.MvPolynomial.Equiv

Goal state before:
pp: R : Type u
S₁ : Type v
S₂ : Type w
inst✝ : CommSemiring R
s : S₂
⊢ ((mapDomainRingEquiv R sumFinsuppAddEquivProdFinsupp).trans curryRingEquiv)
      ((monomial (Finsupp.single (Sum.inr s) 1)) 1) =
    (have __src := singleZeroRingHom;
      { toFun := ⇑(monomial 0), map_one' := ⋯, map_mul' := ⋯, map_zero' := ⋯, map_add' := ⋯ })
      ((monomial (Finsupp.single s 1)) 1)

Tactic:
simp [monomial]

Goal state after:
Module: Mathlib.Algebra.Polynomial.Monic

Goal state before:
pp: R : Type u
inst✝ : Semiring R
p : R[X]
hp : p.Monic
⊢ p.degree ≤ 0 ↔ p = 1

Tactic:
rw [← hp.natDegree_eq_zero, natDegree_eq_zero_iff_degree_le_zero]

Goal state after:
Module: Mathlib.Algebra.Polynomial.Reverse

Goal state before:
pp: R : Type u_1
inst✝ : Semiring R
f : R[X]
n : ℕ
hn : ↑f.natDegree < ↑n
⊢ f.reverse.coeff n = 0

Tactic:
rw [Nat.cast_lt] at hn

Goal state after:
R : Type u_1
inst✝ : Semiring R
f : R[X]
n : ℕ
hn : f.natDegree < n
⊢ f.reverse.coeff n = 0
Module: Mathlib.Algebra.Polynomial.Reverse

Goal state before:
pp: R : Type u_1
inst✝ : Semiring R
p : R[X]
⊢ (p * X).reverse = p.reverse

Tactic:
by
  nontriviality R
  rcases eq_or_ne p 0 with rfl | hp
  · simp
  · simp [reverse, hp]

Goal state after:
Module: Mathlib.Algebra.Polynomial.Monic

Goal state before:
pp: R : Type u
S : Type v
a b : R
m n : ℕ
ι : Type y
inst✝¹ : Semiring R
p✝ q r : R[X]
inst✝ : Semiring S
p : R[X]
hp : p.Monic
hp' : p.natDegree = n
⊢ p.coeff n = 1

Tactic:
← hp',

Goal state after:
R : Type u
S : Type v
a b : R
m n : ℕ
ι : Type y
inst✝¹ : Semiring R
p✝ q r : R[X]
inst✝ : Semiring S
p : R[X]
hp : p.Monic
hp' : p.natDegree = n
⊢ p.coeff p.natDegree = 1
Module: Mathlib.Algebra.Polynomial.Monic

Goal state before:
pp: R : Type u
inst✝ : CommSemiring R
α : Type u_1
f : α → R[X]
hf : ∀ i ∈ Function.mulSupport f, (f i).Monic
⊢ (finprod f).Monic

Tactic:
rw [finprod_def]
  split_ifs
  · exact monic_prod_of_monic _ _ fun a ha => hf a ((Set.Finite.mem_toFinset _).mp ha)
  · exact monic_one

Goal state after:
Module: Mathlib.Algebra.MvPolynomial.Equiv

Goal state before:
pp: R : Type u
inst✝ : CommSemiring R
n : ℕ
p : MvPolynomial (Fin (n + 1)) R
j : Fin n
i : ℕ
⊢ degreeOf j (((finSuccEquiv R n) p).coeff i) ≤ degreeOf j.succ p

Tactic:
rw [degreeOf_eq_sup, degreeOf_eq_sup, Finset.sup_le_iff]

Goal state after:
R : Type u
inst✝ : CommSemiring R
n : ℕ
p : MvPolynomial (Fin (n + 1)) R
j : Fin n
i : ℕ
⊢ ∀ b ∈ (((finSuccEquiv R n) p).coeff i).support, b j ≤ p.support.sup fun m ↦ m j.succ
Module: Mathlib.Algebra.Polynomial.Monic

Goal state before:
pp: case mp
R : Type u
inst✝¹ : CommSemiring R
inst✝ : NoZeroDivisors R
f g : R[X]
hf : f.Monic
hg : g.Monic
hp : (f * g).Monic
h : ∀ (f_1 g_1 : R[X]), f_1.Monic → g_1.Monic → f_1 * g_1 = f * g → f_1.natDegree = 0 ∨ g_1.natDegree = 0
⊢ ¬(0 < g.natDegree ∧ g.natDegree + g.natDegree ≤ (f * g).natDegree)

Tactic:
hf.natDegree_mul hg,

Goal state after:
case mp
R : Type u
inst✝¹ : CommSemiring R
inst✝ : NoZeroDivisors R
f g : R[X]
hf : f.Monic
hg : g.Monic
hp : (f * g).Monic
h : ∀ (f_1 g_1 : R[X]), f_1.Monic → g_1.Monic → f_1 * g_1 = f * g → f_1.natDegree = 0 ∨ g_1.natDegree = 0
⊢ ¬(0 < g.natDegree ∧ g.natDegree + g.natDegree ≤ f.natDegree + g.natDegree)
Module: Mathlib.Algebra.Polynomial.Monic

Goal state before:
pp: case mpr
R : Type u
inst✝¹ : CommSemiring R
inst✝ : NoZeroDivisors R
f g : R[X]
hf : f.Monic
hg : g.Monic
hp : (f * g).Monic
h :
  ∀ (f_1 g_1 : R[X]),
    f_1.Monic → g_1.Monic → f_1 * g_1 = f * g → ¬(0 < g_1.natDegree ∧ g_1.natDegree + g_1.natDegree ≤ (f * g).natDegree)
⊢ f.natDegree = 0 ∨ g.natDegree = 0

Tactic:
hf.natDegree_mul hg,

Goal state after:
case mpr
R : Type u
inst✝¹ : CommSemiring R
inst✝ : NoZeroDivisors R
f g : R[X]
hf : f.Monic
hg : g.Monic
hp : (f * g).Monic
h :
  ∀ (f_1 g_1 : R[X]),
    f_1.Monic →
      g_1.Monic → f_1 * g_1 = f * g → ¬(0 < g_1.natDegree ∧ g_1.natDegree + g_1.natDegree ≤ f.natDegree + g.natDegree)
⊢ f.natDegree = 0 ∨ g.natDegree = 0
Module: Mathlib.RingTheory.Polynomial.Basic

Goal state before:
pp: case a
R : Type u
inst✝¹ : Semiring R
inst✝ : DecidableEq R
n k : ℕ
⊢ k ∈ ↑(range (n + 1)) → k ∈ (fun n ↦ X ^ n) ⁻¹' ↑(degreeLE R ↑n)

Tactic:
hk

Goal state after:
case a
R : Type u
inst✝¹ : Semiring R
inst✝ : DecidableEq R
n k : ℕ
hk : k ∈ ↑(range (n + 1))
⊢ k ∈ (fun n ↦ X ^ n) ⁻¹' ↑(degreeLE R ↑n)
Module: Mathlib.RingTheory.Polynomial.Basic

Goal state before:
pp: case a
R : Type u
inst✝¹ : Semiring R
inst✝ : DecidableEq R
n k : ℕ
⊢ k ∈ ↑(range n) → k ∈ (fun n ↦ X ^ n) ⁻¹' ↑(degreeLT R n)

Tactic:
hk

Goal state after:
case a
R : Type u
inst✝¹ : Semiring R
inst✝ : DecidableEq R
n k : ℕ
hk : k ∈ ↑(range n)
⊢ k ∈ (fun n ↦ X ^ n) ⁻¹' ↑(degreeLT R n)
Module: Mathlib.Algebra.Polynomial.EraseLead

Goal state before:
pp: case refine_2
R : Type u_1
inst✝ : Semiring R
f : R[X]
⊢ (∃ k x, ∃ (_ : x ≠ 0), f = C x * X ^ k) → #f.support = 1

Tactic:
· rintro ⟨k, x, hx, rfl⟩
    rw [support_C_mul_X_pow k hx, card_singleton]

Goal state after:
Module: Mathlib.RingTheory.Adjoin.FG

Goal state before:
pp: case refine_2
R : Type u
A : Type v
inst✝² : CommSemiring R
inst✝¹ : CommSemiring A
inst✝ : Algebra R A
s t : Set A
h1 : (Subalgebra.toSubmodule (adjoin R s)).FG
h2 : (Subalgebra.toSubmodule (adjoin (↥(adjoin R s)) t)).FG
p : Set A
hp : p.Finite
hp' : span R p = Subalgebra.toSubmodule (adjoin R s)
q : Set A
hq : q.Finite
hq' : span (↥(adjoin R s)) q = Subalgebra.toSubmodule (adjoin (↥(adjoin R s)) t)
l : A →₀ ↥(adjoin R s)
hlq : l ∈ Finsupp.supported (↥(adjoin R s)) (↥(adjoin R s)) q
this✝ :
  ∀ [inst : Semiring ↥(adjoin R s)] [inst_1 : AddCommMonoid A] [inst_2 : Module (↥(adjoin R s)) A] {v : A → A}
    (l : A →₀ ↥(adjoin R s)), (Finsupp.linearCombination (↥(adjoin R s)) v) l = l.sum fun i a ↦ a • v i
z : A
hz : z ∈ l.support
this : ↑(l z) ∈ Subalgebra.toSubmodule (adjoin R s)
⊢ ↑(l z) * _root_.id z ∈ span R (p * q)

Tactic:
← hp',

Goal state after:
case refine_2
R : Type u
A : Type v
inst✝² : CommSemiring R
inst✝¹ : CommSemiring A
inst✝ : Algebra R A
s t : Set A
h1 : (Subalgebra.toSubmodule (adjoin R s)).FG
h2 : (Subalgebra.toSubmodule (adjoin (↥(adjoin R s)) t)).FG
p : Set A
hp : p.Finite
hp' : span R p = Subalgebra.toSubmodule (adjoin R s)
q : Set A
hq : q.Finite
hq' : span (↥(adjoin R s)) q = Subalgebra.toSubmodule (adjoin (↥(adjoin R s)) t)
l : A →₀ ↥(adjoin R s)
hlq : l ∈ Finsupp.supported (↥(adjoin R s)) (↥(adjoin R s)) q
this✝ :
  ∀ [inst : Semiring ↥(adjoin R s)] [inst_1 : AddCommMonoid A] [inst_2 : Module (↥(adjoin R s)) A] {v : A → A}
    (l : A →₀ ↥(adjoin R s)), (Finsupp.linearCombination (↥(adjoin R s)) v) l = l.sum fun i a ↦ a • v i
z : A
hz : z ∈ l.support
this : ↑(l z) ∈ span R p
⊢ ↑(l z) * _root_.id z ∈ span R (p * q)
Module: Mathlib.RingTheory.Adjoin.FG

Goal state before:
pp: case refine_2
R : Type u
A : Type v
inst✝² : CommSemiring R
inst✝¹ : CommSemiring A
inst✝ : Algebra R A
s t : Set A
h1 : (Subalgebra.toSubmodule (adjoin R s)).FG
h2 : (Subalgebra.toSubmodule (adjoin (↥(adjoin R s)) t)).FG
p : Set A
hp : p.Finite
hp' : span R p = Subalgebra.toSubmodule (adjoin R s)
q : Set A
hq : q.Finite
hq' : span (↥(adjoin R s)) q = Subalgebra.toSubmodule (adjoin (↥(adjoin R s)) t)
l : A →₀ ↥(adjoin R s)
hlq : l ∈ Finsupp.supported (↥(adjoin R s)) (↥(adjoin R s)) q
this✝ :
  ∀ [inst : Semiring ↥(adjoin R s)] [inst_1 : AddCommMonoid A] [inst_2 : Module (↥(adjoin R s)) A] {v : A → A}
    (l : A →₀ ↥(adjoin R s)), (Finsupp.linearCombination (↥(adjoin R s)) v) l = l.sum fun i a ↦ a • v i
z : A
hz : z ∈ l.support
l2 : A →₀ R
hlp : l2 ∈ Finsupp.supported R R p
hl : (l2.sum fun i a ↦ a • _root_.id i) = ↑(l z)
this :
  ∀ [inst : Semiring R] [inst_1 : AddCommMonoid A] [inst_2 : Module R A] {v : A → A} (l : A →₀ R),
    (Finsupp.linearCombination R v) l = l.sum fun i a ↦ a • v i
⊢ ∀ c ∈ l2.support, (fun a c ↦ c • _root_.id a * _root_.id z) c (l2 c) ∈ span R (p * q)

Tactic:
intro t

Goal state after:
case refine_2
R : Type u
A : Type v
inst✝² : CommSemiring R
inst✝¹ : CommSemiring A
inst✝ : Algebra R A
s t✝ : Set A
h1 : (Subalgebra.toSubmodule (adjoin R s)).FG
h2 : (Subalgebra.toSubmodule (adjoin (↥(adjoin R s)) t✝)).FG
p : Set A
hp : p.Finite
hp' : span R p = Subalgebra.toSubmodule (adjoin R s)
q : Set A
hq : q.Finite
hq' : span (↥(adjoin R s)) q = Subalgebra.toSubmodule (adjoin (↥(adjoin R s)) t✝)
l : A →₀ ↥(adjoin R s)
hlq : l ∈ Finsupp.supported (↥(adjoin R s)) (↥(adjoin R s)) q
this✝ :
  ∀ [inst : Semiring ↥(adjoin R s)] [inst_1 : AddCommMonoid A] [inst_2 : Module (↥(adjoin R s)) A] {v : A → A}
    (l : A →₀ ↥(adjoin R s)), (Finsupp.linearCombination (↥(adjoin R s)) v) l = l.sum fun i a ↦ a • v i
z : A
hz : z ∈ l.support
l2 : A →₀ R
hlp : l2 ∈ Finsupp.supported R R p
hl : (l2.sum fun i a ↦ a • _root_.id i) = ↑(l z)
this :
  ∀ [inst : Semiring R] [inst_1 : AddCommMonoid A] [inst_2 : Module R A] {v : A → A} (l : A →₀ R),
    (Finsupp.linearCombination R v) l = l.sum fun i a ↦ a • v i
t : A
⊢ t ∈ l2.support → (fun a c ↦ c • _root_.id a * _root_.id z) t (l2 t) ∈ span R (p * q)
Module: Mathlib.RingTheory.Adjoin.FG

Goal state before:
pp: R : Type u
A : Type v
inst✝² : CommSemiring R
inst✝¹ : CommSemiring A
inst✝ : Algebra R A
s t : Set A
h1 : (Subalgebra.toSubmodule (adjoin R s)).FG
h2 : (Subalgebra.toSubmodule (adjoin (↥(adjoin R s)) t)).FG
⊢ (Subalgebra.toSubmodule (adjoin R (s ∪ t))).FG

Tactic:
rcases fg_def.1 h1 with ⟨p, hp, hp'⟩
  rcases fg_def.1 h2 with ⟨q, hq, hq'⟩
  refine fg_def.2 ⟨p * q, hp.mul hq, le_antisymm ?_ ?_⟩
  · rw [span_le, Set.mul_subset_iff]
    intro x hx y hy
    change x * y ∈ adjoin R (s ∪ t)
    refine Subalgebra.mul_mem _ ?_ ?_
    · have : x ∈ Subalgebra.toSubmodule (adjoin R s) := by
        rw [← hp']
        exact subset_span hx
      exact adjoin_mono Set.subset_union_left this
    have : y ∈ Subalgebra.toSubmodule (adjoin (adjoin R s) t) := by
      rw [← hq']
      exact subset_span hy
    change y ∈ adjoin R (s ∪ t)
    rwa [adjoin_union_eq_adjoin_adjoin]
  · intro r hr
    change r ∈ adjoin R (s ∪ t) at hr
    rw [adjoin_union_eq_adjoin_adjoin] at hr
    change r ∈ Subalgebra.toSubmodule (adjoin (adjoin R s) t) at hr
    rw [← hq', ← Set.image_id q, Finsupp.mem_span_image_iff_linearCombination (adjoin R s)] at hr
    rcases hr with ⟨l, hlq, rfl⟩
    have := @Finsupp.linearCombination_apply A A (adjoin R s)
    rw [this, Finsupp.sum]
    refine sum_mem ?_
    intro z hz
    change (l z).1 * _ ∈ _
    have : (l z).1 ∈ Subalgebra.toSubmodule (adjoin R s) := (l z).2
    rw [← hp', ← Set.image_id p, Finsupp.mem_span_image_iff_linearCombination R] at this
    rcases this with ⟨l2, hlp, hl⟩
    have := @Finsupp.linearCombination_apply A A R
    rw [this] at hl
    rw [← hl, Finsupp.sum_mul]
    refine sum_mem ?_
    intro t ht
    change _ * _ ∈ _
    rw [smul_mul_assoc]
    refine smul_mem _ _ ?_
    exact subset_span ⟨t, hlp ht, z, hlq hz, rfl⟩

Goal state after:
Module: Mathlib.RingTheory.Polynomial.Basic

Goal state before:
pp: case insert
R : Type u
inst✝ : CommSemiring R
ι : Type u_2
f : ι → R[X]
I : Ideal R
n : ι → ℕ
a : ι
s : Finset ι
ha : a ∉ s
hs : (∀ i ∈ s, ∀ (k : ℕ), (f i).coeff k ∈ I ^ (n i - k)) → ∀ (k : ℕ), (s.prod f).coeff k ∈ I ^ (s.sum n - k)
h : ∀ i ∈ insert a s, ∀ (k : ℕ), (f i).coeff k ∈ I ^ (n i - k)
k : ℕ
⊢ ((insert a s).prod f).coeff k ∈ I ^ ((insert a s).sum n - k)

Tactic:
rw [sum_insert ha, prod_insert ha, coeff_mul]
      apply sum_mem
      rintro ⟨i, j⟩ e
      obtain rfl : i + j = k := mem_antidiagonal.mp e
      apply Ideal.pow_le_pow_right add_tsub_add_le_tsub_add_tsub
      rw [pow_add]
      exact Ideal.mul_mem_mul (by grind) (by grind)

Goal state after:
Module: Mathlib.RingTheory.FiniteType

Goal state before:
pp: R : Type u_1
M : Type u_2
inst✝¹ : CommRing R
inst✝ : AddMonoid M
S : Finset R[M]
hS : adjoin R ↑S = ⊤
this : DecidableEq M := Classical.decEq M
⊢ ↑(S.biUnion fun f ↦ f.coeff.support) = ⋃ f ∈ S, ↑f.coeff.support

Tactic:
simp only [Finset.set_biUnion_coe, Finset.coe_biUnion]

Goal state after:
Module: Mathlib.RingTheory.FiniteType

Goal state before:
pp: R : Type u_1
M : Type u_2
inst✝¹ : CommRing R
inst✝ : Monoid M
S : Finset R[M]
hS : adjoin R ↑S = ⊤
this : DecidableEq M := Classical.decEq M
⊢ ↑(S.biUnion fun f ↦ f.coeff.support) = ⋃ f ∈ S, ↑f.coeff.support

Tactic:
simp only [Finset.set_biUnion_coe, Finset.coe_biUnion]

Goal state after:
Module: Mathlib.RingTheory.Polynomial.Basic

Goal state before:
pp: case h.inr
R : Type u
inst✝ : CommRing R
inst : IsNoetherianRing R
I : Ideal R[X]
M : Submodule R R := ⋯.min (Set.range I.leadingCoeffNth) ⋯
hm : M ∈ Set.range I.leadingCoeffNth
N : ℕ
HN : I.leadingCoeffNth N = M
s : Finset R[X]
hs : Submodule.span R ↑s = I.degreeLE ↑N
hm2 : ∀ (k : ℕ), I.leadingCoeffNth k ≤ M
hs2 : ∀ {x : R[X]}, x ∈ I.degreeLE ↑N → x ∈ Ideal.span ↑s
this✝² : Submodule.span R[X] ↑s = Ideal.span ↑s
k : ℕ
ih : ∀ m < k, ∀ ⦃p : R[X]⦄, p ∈ I → p.natDegree = m → p ∈ Ideal.span ↑s
p : R[X]
hp : p ∈ I
hn : p.natDegree = k
h : N < k
hp0 : p ≠ 0
this✝¹ : 0 ≠ 1
this✝ : Nontrivial R
q : R[X]
hq : q ∈ I
hdq : q.degree ≤ ↑N
hlqp : q.leadingCoeff = p.leadingCoeff
hq0 : q ≠ 0
h1 : p.degree = (q * X ^ (k - q.natDegree)).degree
h2 : p.leadingCoeff = (q * X ^ (k - q.natDegree)).leadingCoeff
this : (p - q * X ^ (k - q.natDegree)).degree < p.degree
⊢ p ∈ Ideal.span ↑s

Tactic:
rw [Polynomial.degree_eq_natDegree hp0] at this

Goal state after:
case h.inr
R : Type u
inst✝ : CommRing R
inst : IsNoetherianRing R
I : Ideal R[X]
M : Submodule R R := ⋯.min (Set.range I.leadingCoeffNth) ⋯
hm : M ∈ Set.range I.leadingCoeffNth
N : ℕ
HN : I.leadingCoeffNth N = M
s : Finset R[X]
hs : Submodule.span R ↑s = I.degreeLE ↑N
hm2 : ∀ (k : ℕ), I.leadingCoeffNth k ≤ M
hs2 : ∀ {x : R[X]}, x ∈ I.degreeLE ↑N → x ∈ Ideal.span ↑s
this✝² : Submodule.span R[X] ↑s = Ideal.span ↑s
k : ℕ
ih : ∀ m < k, ∀ ⦃p : R[X]⦄, p ∈ I → p.natDegree = m → p ∈ Ideal.span ↑s
p : R[X]
hp : p ∈ I
hn : p.natDegree = k
h : N < k
hp0 : p ≠ 0
this✝¹ : 0 ≠ 1
this✝ : Nontrivial R
q : R[X]
hq : q ∈ I
hdq : q.degree ≤ ↑N
hlqp : q.leadingCoeff = p.leadingCoeff
hq0 : q ≠ 0
h1 : p.degree = (q * X ^ (k - q.natDegree)).degree
h2 : p.leadingCoeff = (q * X ^ (k - q.natDegree)).leadingCoeff
this : (p - q * X ^ (k - q.natDegree)).degree < ↑p.natDegree
⊢ p ∈ Ideal.span ↑s
Module: Mathlib.Data.Int.ModEq

Goal state before:
pp: n a b : ℤ
⊢ b + a ≡ b [ZMOD n] ↔ n ∣ a

Tactic:
add_modEq_left_iff

Goal state after:
n a b : ℤ
⊢ n ∣ a ↔ n ∣ a
Module: Mathlib.Data.Int.ModEq

Goal state before:
pp: n a b : ℤ
⊢ a + b ≡ a [ZMOD n] ↔ n ∣ b

Tactic:
add_modEq_left_iff

Goal state after:
n a b : ℤ
⊢ n ∣ b ↔ n ∣ b
Module: Mathlib.Data.Int.ModEq

Goal state before:
pp: n a b c : ℤ
⊢ a ≡ b * n + c [ZMOD n] ↔ a ≡ c [ZMOD n]

Tactic:
by
  rw [add_comm, modEq_add_mul_modulus_iff]

Goal state after:
Module: Mathlib.RingTheory.Ideal.Quotient.Operations

Goal state before:
pp: R✝ : Type u
S : Type v
F : Type w
inst✝⁹ : Ring R✝
inst✝⁸ : Semiring S
R₁ : Type u_1
R₂ : Type u_2
A : Type u_3
B : Type u_4
inst✝⁷ : CommSemiring R₁
inst✝⁶ : CommSemiring R₂
inst✝⁵ : Ring A
inst✝⁴ : Algebra R₁ A
inst✝³ : Algebra R₂ A
R : Type ?u.26
inst✝² : CommRing R
inst✝¹ : Algebra R A
p : Ideal R
P : Ideal A
inst✝ : P.IsTwoSided
h : p ≤ comap (algebraMap R A) P
r₁ : R
a₁ : A
r₂ : R
a₂ : A
hr : r₁ ≈ r₂
ha : a₁ ≈ a₂
this : r₁ - r₂ ∈ comap (algebraMap R A) P
⊢ r₁ • a₁ ≈ r₂ • a₂

Tactic:
rw [mem_comap, map_sub] at this

Goal state after:
R✝ : Type u
S : Type v
F : Type w
inst✝⁹ : Ring R✝
inst✝⁸ : Semiring S
R₁ : Type u_1
R₂ : Type u_2
A : Type u_3
B : Type u_4
inst✝⁷ : CommSemiring R₁
inst✝⁶ : CommSemiring R₂
inst✝⁵ : Ring A
inst✝⁴ : Algebra R₁ A
inst✝³ : Algebra R₂ A
R : Type ?u.26
inst✝² : CommRing R
inst✝¹ : Algebra R A
p : Ideal R
P : Ideal A
inst✝ : P.IsTwoSided
h : p ≤ comap (algebraMap R A) P
r₁ : R
a₁ : A
r₂ : R
a₂ : A
hr : r₁ ≈ r₂
ha : a₁ ≈ a₂
this : (algebraMap R A) r₁ - (algebraMap R A) r₂ ∈ P
⊢ r₁ • a₁ ≈ r₂ • a₂
Module: Mathlib.RingTheory.Ideal.Quotient.Operations

Goal state before:
pp: A : Type u_3
inst✝³ : Ring A
R : Type u_5
inst✝² : CommRing R
I : Ideal A
inst✝¹ : I.IsTwoSided
inst✝ : Algebra R A
⊢ Injective ⇑(algebraMap (R ⧸ comap (algebraMap R A) I) (A ⧸ I))

Tactic:
rintro ⟨a⟩ ⟨b⟩ hab

Goal state after:
case mk.mk
A : Type u_3
inst✝³ : Ring A
R : Type u_5
inst✝² : CommRing R
I : Ideal A
inst✝¹ : I.IsTwoSided
inst✝ : Algebra R A
a₁✝ : R ⧸ comap (algebraMap R A) I
a : R
a₂✝ : R ⧸ comap (algebraMap R A) I
b : R
hab :
  (algebraMap (R ⧸ comap (algebraMap R A) I) (A ⧸ I))
      (Quot.mk (⇑(Submodule.quotientRel (comap (algebraMap R A) I))) a) =
    (algebraMap (R ⧸ comap (algebraMap R A) I) (A ⧸ I))
      (Quot.mk (⇑(Submodule.quotientRel (comap (algebraMap R A) I))) b)
⊢ Quot.mk (⇑(Submodule.quotientRel (comap (algebraMap R A) I))) a =
    Quot.mk (⇑(Submodule.quotientRel (comap (algebraMap R A) I))) b