mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.RingTheory.HahnSeries.Multiplication

Goal state before:
pp: Γ : Type u_1
Γ' : Type u_2
R : Type u_3
S : Type u_4
V : Type u_5
inst✝⁸ : AddCommMonoid Γ
inst✝⁷ : PartialOrder Γ
inst✝⁶ : IsOrderedCancelAddMonoid Γ
inst✝⁵ : PartialOrder Γ'
inst✝⁴ : AddAction Γ Γ'
inst✝³ : IsOrderedCancelVAdd Γ Γ'
inst✝² : AddCommMonoid V
inst✝¹ : Semiring R
inst✝ : Module R V
r : R
x : R⟦Γ⟧
a : HahnModule Γ' R V
⊢ (single 0) r • x • a = r • x • a

Tactic:
← single_zero_smul_eq_smul Γ

Goal state after:
Γ : Type u_1
Γ' : Type u_2
R : Type u_3
S : Type u_4
V : Type u_5
inst✝⁸ : AddCommMonoid Γ
inst✝⁷ : PartialOrder Γ
inst✝⁶ : IsOrderedCancelAddMonoid Γ
inst✝⁵ : PartialOrder Γ'
inst✝⁴ : AddAction Γ Γ'
inst✝³ : IsOrderedCancelVAdd Γ Γ'
inst✝² : AddCommMonoid V
inst✝¹ : Semiring R
inst✝ : Module R V
r : R
x : R⟦Γ⟧
a : HahnModule Γ' R V
⊢ (single 0) r • x • a = (single 0) r • x • a
Module: Mathlib.RingTheory.HahnSeries.Multiplication

Goal state before:
pp: Γ✝ : Type u_1
Γ' : Type u_2
R : Type u_3
S : Type u_4
V✝ : Type u_5
inst✝¹⁴ : AddCommMonoid Γ✝
inst✝¹³ : PartialOrder Γ✝
inst✝¹² : IsOrderedCancelAddMonoid Γ✝
inst✝¹¹ : PartialOrder Γ'
inst✝¹⁰ : AddAction Γ✝ Γ'
inst✝⁹ : IsOrderedCancelVAdd Γ✝ Γ'
inst✝⁸ : AddCommMonoid V✝
Γ : Type u_6
V : Type u_7
inst✝⁷ : Ring R
inst✝⁶ : IsDomain R
inst✝⁵ : AddCommGroup V
inst✝⁴ : AddCommMonoid Γ
inst✝³ : LinearOrder Γ
inst✝² : IsOrderedCancelAddMonoid Γ
inst✝¹ : Module R V
inst✝ : Module.IsTorsionFree R V
x : R⟦Γ⟧
y : HahnModule Γ R V
hxy : x • y = 0
⊢ x = 0 ∨ y = 0

Tactic:
contrapose! hxy

Goal state after:
Γ✝ : Type u_1
Γ' : Type u_2
R : Type u_3
S : Type u_4
V✝ : Type u_5
inst✝¹⁴ : AddCommMonoid Γ✝
inst✝¹³ : PartialOrder Γ✝
inst✝¹² : IsOrderedCancelAddMonoid Γ✝
inst✝¹¹ : PartialOrder Γ'
inst✝¹⁰ : AddAction Γ✝ Γ'
inst✝⁹ : IsOrderedCancelVAdd Γ✝ Γ'
inst✝⁸ : AddCommMonoid V✝
Γ : Type u_6
V : Type u_7
inst✝⁷ : Ring R
inst✝⁶ : IsDomain R
inst✝⁵ : AddCommGroup V
inst✝⁴ : AddCommMonoid Γ
inst✝³ : LinearOrder Γ
inst✝² : IsOrderedCancelAddMonoid Γ
inst✝¹ : Module R V
inst✝ : Module.IsTorsionFree R V
x : R⟦Γ⟧
y : HahnModule Γ R V
hxy : x ≠ 0 ∧ y ≠ 0
⊢ x • y ≠ 0
Module: Mathlib.RingTheory.HahnSeries.Multiplication

Goal state before:
pp: case neg
Γ : Type u_1
R : Type u_3
inst✝³ : AddCommMonoid Γ
inst✝² : PartialOrder Γ
inst✝¹ : IsOrderedCancelAddMonoid Γ
inst✝ : NonUnitalNonAssocSemiring R
a b : Γ
r s : R
y z : Γ
hy : (y, z).1 ∈ ((single a) r).support
hz : (y, z).2 ∈ ((single b) s).support
h : ¬a + (y, z).2 = a + b
⊢ ((single a) r).coeff (y, z).1 * ((single b) s).coeff (y, z).2 = 0

Tactic:
eq_of_mem_support_single hz

Goal state after:
case neg
Γ : Type u_1
R : Type u_3
inst✝³ : AddCommMonoid Γ
inst✝² : PartialOrder Γ
inst✝¹ : IsOrderedCancelAddMonoid Γ
inst✝ : NonUnitalNonAssocSemiring R
a b : Γ
r s : R
y z : Γ
hy : (y, z).1 ∈ ((single a) r).support
hz : (y, z).2 ∈ ((single b) s).support
h : ¬a + b = a + b
⊢ ((single a) r).coeff (y, z).1 * ((single b) s).coeff (y, z).2 = 0
Module: Mathlib.Algebra.Order.Module.HahnEmbedding

Goal state before:
pp: K : Type u_1
inst✝¹¹ : DivisionRing K
inst✝¹⁰ : LinearOrder K
inst✝⁹ : IsOrderedRing K
inst✝⁸ : Archimedean K
M : Type u_2
inst✝⁷ : AddCommGroup M
inst✝⁶ : LinearOrder M
inst✝⁵ : IsOrderedAddMonoid M
inst✝⁴ : Module K M
inst✝³ : IsOrderedModule K M
R : Type u_3
inst✝² : AddCommGroup R
inst✝¹ : LinearOrder R
inst✝ : Module K R
seed : Seed K M R
f : Partial seed
x : ↥(↑f).domain
c : FiniteArchimedeanClass M
hx : ↑x ∈ seed.stratum c
hx' : ↑x ∈ seed.baseEmbedding.domain
heq : ↑⟨↑x, hx'⟩ = ↑x
fx : Π₀ (c : FiniteArchimedeanClass M), ↥(seed.stratum c) := DFinsupp.single c ⟨↑x, hx⟩
⊢ ↑x = fx.sum fun c ↦ ⇑(seed.stratum c).subtype

Tactic:
simp [fx, DFinsupp.sum_single_index]

Goal state after:
Module: Mathlib.Order.Quotient

Goal state before:
pp: case inr.inl
α : Type u_1
s : Setoid α
inst✝ : LinearOrder α
H : ∀ (x : Quotient s), (Quotient.mk s ⁻¹' {x}).OrdConnected
x y z : α
h₁ : ⟦x⟧ = ⟦y⟧
h₂ : y ≤ z
⊢ z < x → ⟦x⟧ = ⟦z⟧

Tactic:
exact fun h ↦ ((H _).out h₁.symm rfl ⟨h₂, h.le⟩).symm

Goal state after:
Module: Mathlib.Order.Quotient

Goal state before:
pp: case h
α : Type u_1
s : Setoid α
inst✝¹ : LinearOrder α
H : ∀ (x : Quotient s), (Quotient.mk s ⁻¹' {x}).OrdConnected
inst✝ : DecidableRel fun x1 x2 ↦ x1 ≈ x2
y : Quotient s
x : α
h₁ : ⟦x⟧ ≤ y
h₂ : y ≤ ⟦x⟧
⊢ ⟦x⟧ = y

Tactic:
induction y using Quotient.inductionOn with

Goal state after:
case h.h
α : Type u_1
s : Setoid α
inst✝¹ : LinearOrder α
H : ∀ (x : Quotient s), (Quotient.mk s ⁻¹' {x}).OrdConnected
inst✝ : DecidableRel fun x1 x2 ↦ x1 ≈ x2
x y : α
h₁ : ⟦x⟧ ≤ ⟦y⟧
h₂ : ⟦y⟧ ≤ ⟦x⟧
⊢ ⟦x⟧ = ⟦y⟧
Module: Mathlib.Algebra.Order.Module.HahnEmbedding

Goal state before:
pp: K : Type u_1
inst✝¹³ : DivisionRing K
inst✝¹² : LinearOrder K
inst✝¹¹ : IsOrderedRing K
inst✝¹⁰ : Archimedean K
M : Type u_2
inst✝⁹ : AddCommGroup M
inst✝⁸ : LinearOrder M
inst✝⁷ : IsOrderedAddMonoid M
inst✝⁶ : Module K M
inst✝⁵ : IsOrderedModule K M
R : Type u_3
inst✝⁴ : AddCommGroup R
inst✝³ : LinearOrder R
inst✝² : Module K R
seed : Seed K M R
f : Partial seed
inst✝¹ : IsOrderedAddMonoid R
inst✝ : Archimedean R
x y : ↥(↑f).domain
⊢ (ofLex (↑↑f x)).orderTop = (ofLex (↑↑f y)).orderTop ↔ ArchimedeanClass.mk ↑x = ArchimedeanClass.mk ↑y

Tactic:
obtain hsubsingleton | hnontrivial := subsingleton_or_nontrivial M

Goal state after:
case inl
K : Type u_1
inst✝¹³ : DivisionRing K
inst✝¹² : LinearOrder K
inst✝¹¹ : IsOrderedRing K
inst✝¹⁰ : Archimedean K
M : Type u_2
inst✝⁹ : AddCommGroup M
inst✝⁸ : LinearOrder M
inst✝⁷ : IsOrderedAddMonoid M
inst✝⁶ : Module K M
inst✝⁵ : IsOrderedModule K M
R : Type u_3
inst✝⁴ : AddCommGroup R
inst✝³ : LinearOrder R
inst✝² : Module K R
seed : Seed K M R
f : Partial seed
inst✝¹ : IsOrderedAddMonoid R
inst✝ : Archimedean R
x y : ↥(↑f).domain
hsubsingleton : Subsingleton M
⊢ (ofLex (↑↑f x)).orderTop = (ofLex (↑↑f y)).orderTop ↔ ArchimedeanClass.mk ↑x = ArchimedeanClass.mk ↑y

case inr
K : Type u_1
inst✝¹³ : DivisionRing K
inst✝¹² : LinearOrder K
inst✝¹¹ : IsOrderedRing K
inst✝¹⁰ : Archimedean K
M : Type u_2
inst✝⁹ : AddCommGroup M
inst✝⁸ : LinearOrder M
inst✝⁷ : IsOrderedAddMonoid M
inst✝⁶ : Module K M
inst✝⁵ : IsOrderedModule K M
R : Type u_3
inst✝⁴ : AddCommGroup R
inst✝³ : LinearOrder R
inst✝² : Module K R
seed : Seed K M R
f : Partial seed
inst✝¹ : IsOrderedAddMonoid R
inst✝ : Archimedean R
x y : ↥(↑f).domain
hnontrivial : Nontrivial M
⊢ (ofLex (↑↑f x)).orderTop = (ofLex (↑↑f y)).orderTop ↔ ArchimedeanClass.mk ↑x = ArchimedeanClass.mk ↑y
Module: Mathlib.RingTheory.HahnSeries.Multiplication

Goal state before:
pp: Γ : Type u_1
Γ' : Type u_2
R : Type u_3
S : Type u_4
V : Type u_5
inst✝⁴ : AddCommMonoid Γ
inst✝³ : LinearOrder Γ
inst✝² : IsOrderedCancelAddMonoid Γ
inst✝¹ : NonUnitalNonAssocSemiring R
inst✝ : NoZeroDivisors R
x✝ y✝ x y : R⟦Γ⟧
hxy : x * y = 0
⊢ x = 0 ∨ y = 0

Tactic:
contrapose! hxy

Goal state after:
Γ : Type u_1
Γ' : Type u_2
R : Type u_3
S : Type u_4
V : Type u_5
inst✝⁴ : AddCommMonoid Γ
inst✝³ : LinearOrder Γ
inst✝² : IsOrderedCancelAddMonoid Γ
inst✝¹ : NonUnitalNonAssocSemiring R
inst✝ : NoZeroDivisors R
x✝ y✝ x y : R⟦Γ⟧
hxy : x ≠ 0 ∧ y ≠ 0
⊢ x * y ≠ 0
Module: Mathlib.RingTheory.Valuation.ValuationSubring

Goal state before:
pp: case pos
K : Type u
inst✝ : Field K
R S : ValuationSubring K
h : R ≤ S
x : K
hx : x ∈ S
hr : x ∈ R
⊢ x ∈ R.ofPrime (R.idealOfLE S h)

Tactic:
exact R.le_ofPrime _ hr

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

Goal state before:
pp: case succ
R : Type u_1
inst✝ : Semiring R
x : R
hx : x ≠ 0
n : ℕ
h : ¬(monomial n) x = 0
k : ℕ
h₁✝ : k + 1 < ((monomial n) x).coeffList.length
h₁ : k + 1 < (x :: List.replicate n 0).length
⊢ ((monomial n) x).coeffList.get ⟨k + 1, h₁✝⟩ = (x :: List.replicate n 0).get ⟨k + 1, h₁⟩

Tactic:
List.length_cons,

Goal state after:
case succ
R : Type u_1
inst✝ : Semiring R
x : R
hx : x ≠ 0
n : ℕ
h : ¬(monomial n) x = 0
k : ℕ
h₁✝¹ : k + 1 < ((monomial n) x).coeffList.length
h₁✝ : k + 1 < (x :: List.replicate n 0).length
h₁ : k + 1 < (List.replicate n 0).length + 1
⊢ ((monomial n) x).coeffList.get ⟨k + 1, h₁✝¹⟩ = (x :: List.replicate n 0).get ⟨k + 1, h₁✝⟩
Module: Mathlib.Algebra.Order.Module.HahnEmbedding

Goal state before:
pp: K : Type u_1
inst✝¹³ : DivisionRing K
inst✝¹² : LinearOrder K
inst✝¹¹ : IsOrderedRing K
inst✝¹⁰ : Archimedean K
M : Type u_2
inst✝⁹ : AddCommGroup M
inst✝⁸ : LinearOrder M
inst✝⁷ : IsOrderedAddMonoid M
inst✝⁶ : Module K M
inst✝⁵ : IsOrderedModule K M
R : Type u_3
inst✝⁴ : AddCommGroup R
inst✝³ : LinearOrder R
inst✝² : Module K R
seed : Seed K M R
f : Partial seed
inst✝¹ : IsOrderedAddMonoid R
inst✝ : Archimedean R
x : M
hx : x ∉ (↑f).domain
c : FiniteArchimedeanClass M
y' : M
hy'✝ : y' ∈ (f.extendFun hx).domain
hy' : y' ∈ (↑f).domain ⊔ K ∙ x
a : M
ha : a ∈ (↑f).domain
b : M
hb : b ∈ K ∙ x
hab : a + b = y'
k : K
hk : k • x = b
⊢ toLex ((truncLTLinearMap K c) (ofLex (↑↑f ⟨a, ha⟩))) +
      toLex ((RingHom.id K) k • (truncLTLinearMap K c) (ofLex (f.eval x))) ∈
    ((↑f).supSpanSingleton x (f.eval x) hx).toFun.range

Tactic:
toLex_smul

Goal state after:
K : Type u_1
inst✝¹³ : DivisionRing K
inst✝¹² : LinearOrder K
inst✝¹¹ : IsOrderedRing K
inst✝¹⁰ : Archimedean K
M : Type u_2
inst✝⁹ : AddCommGroup M
inst✝⁸ : LinearOrder M
inst✝⁷ : IsOrderedAddMonoid M
inst✝⁶ : Module K M
inst✝⁵ : IsOrderedModule K M
R : Type u_3
inst✝⁴ : AddCommGroup R
inst✝³ : LinearOrder R
inst✝² : Module K R
seed : Seed K M R
f : Partial seed
inst✝¹ : IsOrderedAddMonoid R
inst✝ : Archimedean R
x : M
hx : x ∉ (↑f).domain
c : FiniteArchimedeanClass M
y' : M
hy'✝ : y' ∈ (f.extendFun hx).domain
hy' : y' ∈ (↑f).domain ⊔ K ∙ x
a : M
ha : a ∈ (↑f).domain
b : M
hb : b ∈ K ∙ x
hab : a + b = y'
k : K
hk : k • x = b
⊢ toLex ((truncLTLinearMap K c) (ofLex (↑↑f ⟨a, ha⟩))) +
      (RingHom.id K) k • toLex ((truncLTLinearMap K c) (ofLex (f.eval x))) ∈
    ((↑f).supSpanSingleton x (f.eval x) hx).toFun.range
Module: Mathlib.Algebra.Polynomial.Degree.IsMonicOfDegree

Goal state before:
pp: R : Type u_1
inst✝¹ : Semiring R
inst✝ : Subsingleton R
p : R[X]
n : ℕ
⊢ p.IsMonicOfDegree n ↔ n = 0

Tactic:
Subsingleton.eq_one p

Goal state after:
R : Type u_1
inst✝¹ : Semiring R
inst✝ : Subsingleton R
p : R[X]
n : ℕ
⊢ IsMonicOfDegree 1 n ↔ n = 0
Module: Mathlib.Algebra.Order.Module.HahnEmbedding

Goal state before:
pp: K : Type u_1
inst✝¹³ : DivisionRing K
inst✝¹² : LinearOrder K
inst✝¹¹ : IsOrderedRing K
inst✝¹⁰ : Archimedean K
M : Type u_2
inst✝⁹ : AddCommGroup M
inst✝⁸ : LinearOrder M
inst✝⁷ : IsOrderedAddMonoid M
inst✝⁶ : Module K M
inst✝⁵ : IsOrderedModule K M
R : Type u_3
inst✝⁴ : AddCommGroup R
inst✝³ : LinearOrder R
inst✝² : Module K R
seed : Seed K M R
inst✝¹ : IsOrderedAddMonoid R
inst✝ : Archimedean R
f : Partial seed
hf : ∀ (b : Partial seed), ¬f < b
⊢ ∀ (x : M), x ∈ (↑f).domain

Tactic:
contrapose! hf with hx

Goal state after:
K : Type u_1
inst✝¹³ : DivisionRing K
inst✝¹² : LinearOrder K
inst✝¹¹ : IsOrderedRing K
inst✝¹⁰ : Archimedean K
M : Type u_2
inst✝⁹ : AddCommGroup M
inst✝⁸ : LinearOrder M
inst✝⁷ : IsOrderedAddMonoid M
inst✝⁶ : Module K M
inst✝⁵ : IsOrderedModule K M
R : Type u_3
inst✝⁴ : AddCommGroup R
inst✝³ : LinearOrder R
inst✝² : Module K R
seed : Seed K M R
inst✝¹ : IsOrderedAddMonoid R
inst✝ : Archimedean R
f : Partial seed
hx : ∃ x, x ∉ (↑f).domain
⊢ ∃ b, f < b
Module: Mathlib.Algebra.Polynomial.Mirror

Goal state before:
pp: case refine_5
R : Type u_1
inst✝ : Semiring R
p : R[X]
⊢ ∀ a ∈ Finset.range (p.natDegree + 1),
    p.mirror.coeff a ≠ 0 → p.mirror.coeff a = p.coeff ((revAt (p.natDegree + p.natTrailingDegree)) a)

Tactic:
exact fun n _ _ => p.coeff_mirror n

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

Goal state before:
pp: R : Type u_1
inst✝ : Semiring R
p : R[X]
n : ℕ
⊢ p.coeff ((revAt (p.natDegree + p.natTrailingDegree)) ((revAt (p.natDegree + p.mirror.natTrailingDegree)) n)) =
    p.coeff n

Tactic:
mirror_natTrailingDegree,

Goal state after:
R : Type u_1
inst✝ : Semiring R
p : R[X]
n : ℕ
⊢ p.coeff ((revAt (p.natDegree + p.natTrailingDegree)) ((revAt (p.natDegree + p.natTrailingDegree)) n)) = p.coeff n
Module: Mathlib.Algebra.Polynomial.Mirror

Goal state before:
pp: R : Type u_1
inst✝ : Semiring R
p : R[X]
⊢ p.mirror.coeff p.mirror.natTrailingDegree = p.coeff p.natDegree

Tactic:
mirror_natTrailingDegree,

Goal state after:
R : Type u_1
inst✝ : Semiring R
p : R[X]
⊢ p.mirror.coeff p.natTrailingDegree = p.coeff p.natDegree
Module: Mathlib.Algebra.Polynomial.Mirror

Goal state before:
pp: case neg
R : Type u_1
inst✝¹ : Semiring R
p : R[X]
inst✝ : NoZeroDivisors R
hp : ¬p = 0
⊢ p.natTrailingDegree + p.mirror.natTrailingDegree = 2 * p.natTrailingDegree

Tactic:
mirror_natTrailingDegree,

Goal state after:
case neg
R : Type u_1
inst✝¹ : Semiring R
p : R[X]
inst✝ : NoZeroDivisors R
hp : ¬p = 0
⊢ p.natTrailingDegree + p.natTrailingDegree = 2 * p.natTrailingDegree
Module: Mathlib.Algebra.Polynomial.Mirror

Goal state before:
pp: case not_isUnit
R : Type u_1
inst✝¹ : CommRing R
inst✝ : NoZeroDivisors R
f : R[X]
h1 : ¬IsUnit f
h2 : ∀ (k : R[X]), f * f.mirror = k * k.mirror → k = f ∨ k = -f ∨ k = f.mirror ∨ k = -f.mirror
h3 : IsRelPrime f f.mirror
⊢ ¬IsUnit f

Tactic:
exact h1

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

Goal state before:
pp: R : Type u_1
inst✝¹ : Semiring R
inst✝ : DecidableEq R
n : ℕ
v : Fin n → R
⊢ (ofFn n) v = ∑ i, (monomial ↑i) (v i)

Tactic:
by_cases h : n = 0

Goal state after:
case pos
R : Type u_1
inst✝¹ : Semiring R
inst✝ : DecidableEq R
n : ℕ
v : Fin n → R
h : n = 0
⊢ (ofFn n) v = ∑ i, (monomial ↑i) (v i)

case neg
R : Type u_1
inst✝¹ : Semiring R
inst✝ : DecidableEq R
n : ℕ
v : Fin n → R
h : ¬n = 0
⊢ (ofFn n) v = ∑ i, (monomial ↑i) (v i)
Module: Mathlib.Algebra.Polynomial.PartialFractions

Goal state before:
pp: case succ.refine_2
R : Type u_1
inst✝¹ : CommRing R
inst✝ : Nontrivial R
f g : R[X]
hg : g.Monic
n : ℕ
q : R[X]
r : Fin n → R[X]
hr : ∀ (i : Fin n), (r i).degree < g.degree
hf : f = q * g ^ n + ∑ i, r i * g ^ ↑i
⊢ q * g ^ n + ∑ i, r i * g ^ ↑i =
    q %ₘ g * g ^ n + q /ₘ g * g * g ^ n + ∑ i, Fin.snoc r (q %ₘ g) i.castSucc * g ^ ↑i.castSucc

Tactic:
← add_mul,

Goal state after:
case succ.refine_2
R : Type u_1
inst✝¹ : CommRing R
inst✝ : Nontrivial R
f g : R[X]
hg : g.Monic
n : ℕ
q : R[X]
r : Fin n → R[X]
hr : ∀ (i : Fin n), (r i).degree < g.degree
hf : f = q * g ^ n + ∑ i, r i * g ^ ↑i
⊢ q * g ^ n + ∑ i, r i * g ^ ↑i = (q %ₘ g + q /ₘ g * g) * g ^ n + ∑ i, Fin.snoc r (q %ₘ g) i.castSucc * g ^ ↑i.castSucc
Module: Mathlib.Data.List.Destutter

Goal state before:
pp: α : Type u_1
β : Type u_2
R : α → α → Prop
inst✝¹ : DecidableRel R
R₂ : β → β → Prop
inst✝ : DecidableRel R₂
f : α → β
a b : α
l : List α
hl : ∀ (a_1 : α), a_1 ∈ a :: b :: l → ∀ (b_1 : α), b_1 ∈ a :: b :: l → (R a_1 b_1 ↔ R₂ (f a_1) (f b_1))
⊢ map f (destutter R (a :: b :: l)) = destutter R₂ (map f (a :: b :: l))

Tactic:
by
    have := hl a (by simp) b (by simp)
    simp_rw [map_cons, destutter_cons_cons, ← this]
    by_cases hr : R a b <;>
      simp [hr, ← destutter_cons', map_destutter fun c hc d hd ↦ hl _ (cons_subset_cons _
        (subset_cons_self _ _) hc) _ (cons_subset_cons _ (subset_cons_self _ _) hd),
        map_destutter fun c hc d hd ↦ hl _ (subset_cons_self _ _ hc) _ (subset_cons_self _ _ hd)]

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

Goal state before:
pp: case succ.snoc.snoc
R : Type u_1
inst✝ : CommRing R
g : R[X]
hg : g.Monic
n : ℕ
ih :
  ∀ {q₁ q₂ : R[X]} {r₁ r₂ : Fin n → R[X]},
    (∀ (i : Fin n), (r₁ i).degree < g.degree) →
      (∀ (i : Fin n), (r₂ i).degree < g.degree) →
        q₁ * g ^ n + ∑ i, r₁ i * g ^ ↑i = q₂ * g ^ n + ∑ i, r₂ i * g ^ ↑i → q₁ = q₂ ∧ r₁ = r₂
q₁ q₂ : R[X]
rs₁ : Fin n → R[X]
r₁ : R[X]
hr₁ : ∀ (i : Fin (n + 1)), (Fin.snoc rs₁ r₁ i).degree < g.degree
rs₂ : Fin n → R[X]
r₂ : R[X]
hr₂ : ∀ (i : Fin (n + 1)), (Fin.snoc rs₂ r₂ i).degree < g.degree
hf : r₁ * g ^ n + q₁ * g * g ^ n + ∑ x, rs₁ x * g ^ ↑x = r₂ * g ^ n + q₂ * g * g ^ n + ∑ x, rs₂ x * g ^ ↑x
⊢ q₁ = q₂ ∧ Fin.snoc rs₁ r₁ = Fin.snoc rs₂ r₂

Tactic:
← add_mul,

Goal state after:
case succ.snoc.snoc
R : Type u_1
inst✝ : CommRing R
g : R[X]
hg : g.Monic
n : ℕ
ih :
  ∀ {q₁ q₂ : R[X]} {r₁ r₂ : Fin n → R[X]},
    (∀ (i : Fin n), (r₁ i).degree < g.degree) →
      (∀ (i : Fin n), (r₂ i).degree < g.degree) →
        q₁ * g ^ n + ∑ i, r₁ i * g ^ ↑i = q₂ * g ^ n + ∑ i, r₂ i * g ^ ↑i → q₁ = q₂ ∧ r₁ = r₂
q₁ q₂ : R[X]
rs₁ : Fin n → R[X]
r₁ : R[X]
hr₁ : ∀ (i : Fin (n + 1)), (Fin.snoc rs₁ r₁ i).degree < g.degree
rs₂ : Fin n → R[X]
r₂ : R[X]
hr₂ : ∀ (i : Fin (n + 1)), (Fin.snoc rs₂ r₂ i).degree < g.degree
hf : (r₁ + q₁ * g) * g ^ n + ∑ x, rs₁ x * g ^ ↑x = r₂ * g ^ n + q₂ * g * g ^ n + ∑ x, rs₂ x * g ^ ↑x
⊢ q₁ = q₂ ∧ Fin.snoc rs₁ r₁ = Fin.snoc rs₂ r₂
Module: Mathlib.Algebra.Polynomial.PartialFractions

Goal state before:
pp: case succ.snoc.snoc
R : Type u_1
inst✝ : CommRing R
g : R[X]
hg : g.Monic
n : ℕ
ih :
  ∀ {q₁ q₂ : R[X]} {r₁ r₂ : Fin n → R[X]},
    (∀ (i : Fin n), (r₁ i).degree < g.degree) →
      (∀ (i : Fin n), (r₂ i).degree < g.degree) →
        q₁ * g ^ n + ∑ i, r₁ i * g ^ ↑i = q₂ * g ^ n + ∑ i, r₂ i * g ^ ↑i → q₁ = q₂ ∧ r₁ = r₂
q₁ q₂ : R[X]
rs₁ : Fin n → R[X]
r₁ : R[X]
hr₁ : ∀ (i : Fin (n + 1)), (Fin.snoc rs₁ r₁ i).degree < g.degree
rs₂ : Fin n → R[X]
r₂ : R[X]
hr₂ : ∀ (i : Fin (n + 1)), (Fin.snoc rs₂ r₂ i).degree < g.degree
hf : (r₁ + q₁ * g) * g ^ n + ∑ x, rs₁ x * g ^ ↑x = r₂ * g ^ n + q₂ * g * g ^ n + ∑ x, rs₂ x * g ^ ↑x
⊢ q₁ = q₂ ∧ Fin.snoc rs₁ r₁ = Fin.snoc rs₂ r₂

Tactic:
← add_mul,

Goal state after:
case succ.snoc.snoc
R : Type u_1
inst✝ : CommRing R
g : R[X]
hg : g.Monic
n : ℕ
ih :
  ∀ {q₁ q₂ : R[X]} {r₁ r₂ : Fin n → R[X]},
    (∀ (i : Fin n), (r₁ i).degree < g.degree) →
      (∀ (i : Fin n), (r₂ i).degree < g.degree) →
        q₁ * g ^ n + ∑ i, r₁ i * g ^ ↑i = q₂ * g ^ n + ∑ i, r₂ i * g ^ ↑i → q₁ = q₂ ∧ r₁ = r₂
q₁ q₂ : R[X]
rs₁ : Fin n → R[X]
r₁ : R[X]
hr₁ : ∀ (i : Fin (n + 1)), (Fin.snoc rs₁ r₁ i).degree < g.degree
rs₂ : Fin n → R[X]
r₂ : R[X]
hr₂ : ∀ (i : Fin (n + 1)), (Fin.snoc rs₂ r₂ i).degree < g.degree
hf : (r₁ + q₁ * g) * g ^ n + ∑ x, rs₁ x * g ^ ↑x = (r₂ + q₂ * g) * g ^ n + ∑ x, rs₂ x * g ^ ↑x
⊢ q₁ = q₂ ∧ Fin.snoc rs₁ r₁ = Fin.snoc rs₂ r₂
Module: Mathlib.Algebra.Polynomial.SpecificDegree

Goal state before:
pp: case neg
K : Type u_1
inst✝ : Field K
p : K[X]
hdeg : 1 ≤ p.natDegree ∧ p.natDegree ≤ 3
hnot : ∀ (x : K), ¬p.IsRoot x
hdeg2 : ¬2 ≤ p.natDegree
⊢ p.degree = 1

Tactic:
← Nat.cast_one,

Goal state after:
case neg
K : Type u_1
inst✝ : Field K
p : K[X]
hdeg : 1 ≤ p.natDegree ∧ p.natDegree ≤ 3
hnot : ∀ (x : K), ¬p.IsRoot x
hdeg2 : ¬2 ≤ p.natDegree
⊢ p.degree = ↑1
Module: Mathlib.Algebra.Polynomial.UnitTrinomial

Goal state before:
pp: R : Type u_1
inst✝ : Semiring R
k m n : ℕ
u v w : R
hkm : k < m
hmn : m < n
hw : w ≠ 0
⊢ (trinomial k m n u v w).natDegree = n

Tactic:
by
  refine
    natDegree_eq_of_degree_eq_some
      ((Finset.sup_le fun i h => ?_).antisymm <|
        le_degree_of_ne_zero <| by rwa [trinomial_leading_coeff' hkm hmn])
  replace h := support_trinomial_subset k m n u v w h
  rw [mem_insert, mem_insert, mem_singleton] at h
  rcases h with (rfl | rfl | rfl)
  · exact WithBot.coe_le_coe.mpr (hkm.trans hmn).le
  · exact WithBot.coe_le_coe.mpr hmn.le
  · exact le_rfl

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

Goal state before:
pp: case cons.refine_2
R : Type u_1
inst✝² : CommRing R
inst✝¹ : Nontrivial R
ι : Type u_2
inst✝ : DecidableEq ι
f : R[X]
g : ι → R[X]
i : ι
s : Finset ι
hi : i ∉ s
ih :
  (∀ i ∈ s, (g i).Monic) →
    ((↑s).Pairwise fun i j ↦ IsCoprime (g i) (g j)) →
      ∃ q r, (∀ i ∈ s, (r i).degree < (g i).degree) ∧ f = q * ∏ i ∈ s, g i + ∑ i ∈ s, r i * ∏ k ∈ s.erase i, g k
hg : (g i).Monic ∧ ∀ x ∈ s, (g x).Monic
hgg : ((↑s).Pairwise fun i j ↦ IsCoprime (g i) (g j)) ∧ ∀ b ∈ ↑s, i ≠ b → IsCoprime (g i) (g b) ∧ IsCoprime (g b) (g i)
q : R[X]
r : ι → R[X]
hf : f = q * ∏ i ∈ s, g i + ∑ i ∈ s, r i * ∏ k ∈ s.erase i, g k
hjs : ∀ {j : ι}, j ∈ s → i ≠ j
a b : ι → R[X]
hab : ∀ j ∈ s, a j * g i + b j * g j = 1
⊢ q * ∏ i ∈ s, g i + ∑ i ∈ s, r i * ∏ k ∈ s.erase i, g k =
    (q + ∑ j ∈ s, r j * b j %ₘ g i) /ₘ g i * g i * ∏ x ∈ s, g x +
        (q + ∑ j ∈ s, r j * b j %ₘ g i) %ₘ g i * ∏ k ∈ s, g k +
      ((∑ j ∈ s, (r j * b j /ₘ g i + r j * a j /ₘ g j)) * (g i * ∏ x ∈ s, g x) +
        ∑ x ∈ s,
          Function.update (fun j ↦ r j * a j %ₘ g j) i ((q + ∑ j ∈ s, r j * b j %ₘ g i) %ₘ g i) x *
            ∏ k ∈ (Finset.cons i s hi).erase x, g k)

Tactic:
← add_mul,

Goal state after:
case cons.refine_2
R : Type u_1
inst✝² : CommRing R
inst✝¹ : Nontrivial R
ι : Type u_2
inst✝ : DecidableEq ι
f : R[X]
g : ι → R[X]
i : ι
s : Finset ι
hi : i ∉ s
ih :
  (∀ i ∈ s, (g i).Monic) →
    ((↑s).Pairwise fun i j ↦ IsCoprime (g i) (g j)) →
      ∃ q r, (∀ i ∈ s, (r i).degree < (g i).degree) ∧ f = q * ∏ i ∈ s, g i + ∑ i ∈ s, r i * ∏ k ∈ s.erase i, g k
hg : (g i).Monic ∧ ∀ x ∈ s, (g x).Monic
hgg : ((↑s).Pairwise fun i j ↦ IsCoprime (g i) (g j)) ∧ ∀ b ∈ ↑s, i ≠ b → IsCoprime (g i) (g b) ∧ IsCoprime (g b) (g i)
q : R[X]
r : ι → R[X]
hf : f = q * ∏ i ∈ s, g i + ∑ i ∈ s, r i * ∏ k ∈ s.erase i, g k
hjs : ∀ {j : ι}, j ∈ s → i ≠ j
a b : ι → R[X]
hab : ∀ j ∈ s, a j * g i + b j * g j = 1
⊢ q * ∏ i ∈ s, g i + ∑ i ∈ s, r i * ∏ k ∈ s.erase i, g k =
    ((q + ∑ j ∈ s, r j * b j %ₘ g i) /ₘ g i * g i + (q + ∑ j ∈ s, r j * b j %ₘ g i) %ₘ g i) * ∏ x ∈ s, g x +
      ((∑ j ∈ s, (r j * b j /ₘ g i + r j * a j /ₘ g j)) * (g i * ∏ x ∈ s, g x) +
        ∑ x ∈ s,
          Function.update (fun j ↦ r j * a j %ₘ g j) i ((q + ∑ j ∈ s, r j * b j %ₘ g i) %ₘ g i) x *
            ∏ k ∈ (Finset.cons i s hi).erase x, g k)
Module: Mathlib.Algebra.Polynomial.PartialFractions

Goal state before:
pp: case cons.refine_2
R : Type u_1
inst✝² : CommRing R
inst✝¹ : Nontrivial R
ι : Type u_2
inst✝ : DecidableEq ι
f : R[X]
g : ι → R[X]
i : ι
s : Finset ι
hi : i ∉ s
ih :
  (∀ i ∈ s, (g i).Monic) →
    ((↑s).Pairwise fun i j ↦ IsCoprime (g i) (g j)) →
      ∃ q r, (∀ i ∈ s, (r i).degree < (g i).degree) ∧ f = q * ∏ i ∈ s, g i + ∑ i ∈ s, r i * ∏ k ∈ s.erase i, g k
hg : (g i).Monic ∧ ∀ x ∈ s, (g x).Monic
hgg : ((↑s).Pairwise fun i j ↦ IsCoprime (g i) (g j)) ∧ ∀ b ∈ ↑s, i ≠ b → IsCoprime (g i) (g b) ∧ IsCoprime (g b) (g i)
q : R[X]
r : ι → R[X]
hf : f = q * ∏ i ∈ s, g i + ∑ i ∈ s, r i * ∏ k ∈ s.erase i, g k
hjs : ∀ {j : ι}, j ∈ s → i ≠ j
a b : ι → R[X]
hab : ∀ j ∈ s, a j * g i + b j * g j = 1
j : ι
hj : j ∈ s
⊢ r j = r j * b j %ₘ g i * g j + r j * b j /ₘ g i * g i * g j + r j * a j /ₘ g j * g i * g j + r j * a j %ₘ g j * g i

Tactic:
← add_mul,

Goal state after:
case cons.refine_2
R : Type u_1
inst✝² : CommRing R
inst✝¹ : Nontrivial R
ι : Type u_2
inst✝ : DecidableEq ι
f : R[X]
g : ι → R[X]
i : ι
s : Finset ι
hi : i ∉ s
ih :
  (∀ i ∈ s, (g i).Monic) →
    ((↑s).Pairwise fun i j ↦ IsCoprime (g i) (g j)) →
      ∃ q r, (∀ i ∈ s, (r i).degree < (g i).degree) ∧ f = q * ∏ i ∈ s, g i + ∑ i ∈ s, r i * ∏ k ∈ s.erase i, g k
hg : (g i).Monic ∧ ∀ x ∈ s, (g x).Monic
hgg : ((↑s).Pairwise fun i j ↦ IsCoprime (g i) (g j)) ∧ ∀ b ∈ ↑s, i ≠ b → IsCoprime (g i) (g b) ∧ IsCoprime (g b) (g i)
q : R[X]
r : ι → R[X]
hf : f = q * ∏ i ∈ s, g i + ∑ i ∈ s, r i * ∏ k ∈ s.erase i, g k
hjs : ∀ {j : ι}, j ∈ s → i ≠ j
a b : ι → R[X]
hab : ∀ j ∈ s, a j * g i + b j * g j = 1
j : ι
hj : j ∈ s
⊢ r j = (r j * b j %ₘ g i + r j * b j /ₘ g i * g i) * g j + r j * a j /ₘ g j * g i * g j + r j * a j %ₘ g j * g i
Module: Mathlib.Algebra.Polynomial.UnitTrinomial

Goal state before:
pp: case refine_1
k m n : ℕ
hkm : k < m
hmn : m < n
u v w : ℤˣ
⊢ ↑u ^ 2 + (↑v ^ 2 + ↑w ^ 2) = 3

Tactic:
simp_rw [← Units.val_pow_eq_pow_val, Int.units_sq, Units.val_one]

Goal state after:
case refine_1
k m n : ℕ
hkm : k < m
hmn : m < n
u v w : ℤˣ
⊢ 1 + (1 + 1) = 3