mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.Algebra.MonoidAlgebra.Degree

Goal state before:
pp: R : Type u_7
A : Type u_8
B : Type u_9
inst✝⁶ : CommSemiring R
inst✝⁵ : AddCommMonoid A
inst✝⁴ : AddCommMonoid B
inst✝³ : SemilatticeSup B
inst✝² : OrderBot B
inst✝¹ : AddLeftMono B
inst✝ : AddRightMono B
D : A → B
hzero : D 0 = 0
hadd : ∀ (a1 a2 : A), D (a1 + a2) = D a1 + D a2
ι : Type u_10
s✝ : Finset ι
f : ι → R[A]
i : ι
s : Finset ι
his : i ∉ s
ih : supDegree D (∏ i ∈ s, f i) ≤ ∑ i ∈ s, supDegree D (f i)
⊢ supDegree D (f i) + supDegree D (∏ x ∈ s, f x) ≤ supDegree D (f i) + ∑ x ∈ s, supDegree D (f x)

Tactic:
gcongr

Goal state after:
Module: Mathlib.Algebra.Polynomial.Degree.Operations

Goal state before:
pp: case neg
R : Type u
inst✝ : Semiring R
p q : R[X]
H : (p + q).natDegree = 0
h₁ : ¬p.natDegree = 0
⊢ p.natDegree = q.natDegree

Tactic:
apply natDegree_eq_of_natDegree_add_lt_left; rwa [H, Nat.pos_iff_ne_zero]

Goal state after:
Module: Mathlib.Algebra.Polynomial.Degree.Operations

Goal state before:
pp: R : Type u
inst✝ : Semiring R
p q : R[X]
h : p.leadingCoeff * q.leadingCoeff ≠ 0
⊢ p = 0 → p.leadingCoeff * q.leadingCoeff = 0

Tactic:
exact fun hp => by rw [hp, leadingCoeff_zero, zero_mul]

Goal state after:
Module: Mathlib.Algebra.Polynomial.Degree.Operations

Goal state before:
pp: R : Type u
n✝ : ℕ
inst✝ : Semiring R
p : R[X]
n : ℕ
ih : p.leadingCoeff ^ n ≠ 0 → (p ^ n).leadingCoeff = p.leadingCoeff ^ n
h : p.leadingCoeff ^ n.succ ≠ 0
h₁ : p.leadingCoeff ^ n = 0
⊢ p.leadingCoeff ^ n.succ = 0

Tactic:
rw [pow_succ, h₁, zero_mul]

Goal state after:
Module: Mathlib.Algebra.Polynomial.Degree.Operations

Goal state before:
pp: R : Type u
inst✝ : Semiring R
p : R[X]
n : ℕ
h : p.leadingCoeff ^ (n + 1) ≠ 0
h₁ : p.leadingCoeff ^ n = 0
⊢ p.leadingCoeff ^ (n + 1) = 0

Tactic:
rw [pow_succ, h₁, zero_mul]

Goal state after:
Module: Mathlib.Algebra.Polynomial.Degree.SmallDegree

Goal state before:
pp: R : Type u
inst✝ : Semiring R
p : R[X]
hm : p.Monic
hnd : p.natDegree = 1
⊢ p = C 1 * X + C (p.coeff 0)

Tactic:
← hm.coeff_natDegree,

Goal state after:
R : Type u
inst✝ : Semiring R
p : R[X]
hm : p.Monic
hnd : p.natDegree = 1
⊢ p = C (p.coeff p.natDegree) * X + C (p.coeff 0)
Module: Mathlib.Algebra.Polynomial.Degree.Operations

Goal state before:
pp: R : Type u
inst✝ : Semiring R
p : R[X]
i : ℕ
hi : (p ^ i).coeff (i * p.natDegree) = p.leadingCoeff ^ i
hp1 : p.leadingCoeff ^ i = 0
hp2 : ¬p ^ i = 0
h1 : (p ^ i).natDegree < i * p.natDegree
⊢ (p ^ i).natDegree + p.natDegree < i * p.natDegree + p.natDegree

Tactic:
gcongr

Goal state after:
Module: Mathlib.Algebra.Polynomial.Degree.Operations

Goal state before:
pp: case h
R : Type u
inst✝ : Semiring R
df dg : ℕ
f g : R[X]
hdf : f.natDegree ≤ df
hdg : g.natDegree ≤ dg
⊢ (df, dg) ∈ antidiagonal (df + dg)

pp: case h₀
R : Type u
inst✝ : Semiring R
df dg : ℕ
f g : R[X]
hdf : f.natDegree ≤ df
hdg : g.natDegree ≤ dg
⊢ ∀ b ∈ antidiagonal (df + dg), b ≠ (df, dg) → f.coeff b.1 * g.coeff b.2 = 0

Tactic:
· rw [mem_antidiagonal]

Goal state after:
case h₀
R : Type u
inst✝ : Semiring R
df dg : ℕ
f g : R[X]
hdf : f.natDegree ≤ df
hdg : g.natDegree ≤ dg
⊢ ∀ b ∈ antidiagonal (df + dg), b ≠ (df, dg) → f.coeff b.1 * g.coeff b.2 = 0
Module: Mathlib.Algebra.Polynomial.Degree.Operations

Goal state before:
pp: R : Type u
inst✝¹ : Semiring R
inst✝ : Nontrivial R
p : R[X]
hp : p ≠ 0
⊢ (X * p).natDegree = p.natDegree + 1

Tactic:
commute_X p,

Goal state after:
R : Type u
inst✝¹ : Semiring R
inst✝ : Nontrivial R
p : R[X]
hp : p ≠ 0
⊢ (p * X).natDegree = p.natDegree + 1
Module: Mathlib.Algebra.Polynomial.Eval.Degree

Goal state before:
pp: R : Type u
inst✝ : Semiring R
p q : R[X]
hqd0 : q.natDegree ≠ 0
b : ℕ
hbs : b ∈ p.support
hbp : b ≠ p.natDegree
⊢ b * q.natDegree < p.natDegree * q.natDegree

Tactic:
gcongr

Goal state after:
case hbc
R : Type u
inst✝ : Semiring R
p q : R[X]
hqd0 : q.natDegree ≠ 0
b : ℕ
hbs : b ∈ p.support
hbp : b ≠ p.natDegree
⊢ b < p.natDegree
Module: Mathlib.Algebra.Notation.Lemmas

Goal state before:
pp: α : Type u_1
inst✝² : One α
p : Prop
inst✝¹ : Decidable p
a b : α
inst✝ : LE α
ha : 1 ≤ a
hb : 1 ≤ b
⊢ 1 ≤ if p then a else b

Tactic:
split <;> assumption

Goal state after:
Module: Mathlib.Algebra.Notation.Lemmas

Goal state before:
pp: α : Type u_1
inst✝² : One α
p : Prop
inst✝¹ : Decidable p
a b : α
inst✝ : LE α
ha : a ≤ 1
hb : b ≤ 1
⊢ (if p then a else b) ≤ 1

Tactic:
split <;> assumption

Goal state after:
Module: Mathlib.Algebra.Notation.Lemmas

Goal state before:
pp: α : Type u_1
inst✝² : One α
p : Prop
inst✝¹ : Decidable p
a b : α
inst✝ : LT α
ha : 1 < a
hb : 1 < b
⊢ 1 < if p then a else b

Tactic:
split <;> assumption

Goal state after:
Module: Mathlib.Algebra.Notation.Lemmas

Goal state before:
pp: α : Type u_1
inst✝² : One α
p : Prop
inst✝¹ : Decidable p
a b : α
inst✝ : LT α
ha : a < 1
hb : b < 1
⊢ (if p then a else b) < 1

Tactic:
split <;> assumption

Goal state after:
Module: Mathlib.Order.PiLex

Goal state before:
pp: case refine_1
ι : Type u_1
β : ι → Type u_2
r : ι → ι → Prop
s : {i : ι} → β i → β i → Prop
inst✝² : Preorder ι
inst✝¹ : (i : ι) → LT (β i)
inst✝ : ∀ (i : ι), DenselyOrdered (β i)
a₁✝ a₂ : Lex ((i : ι) → β i)
i : ι
h : ∀ (j : ι), (fun x1 x2 ↦ x1 < x2) j i → a₁✝ j = a₂ j
hi : a₁✝ i < a₂ i
a : β i
ha₁ : a₁✝ i < a
ha₂ : a < a₂ i
j : ι
hj : (fun x1 x2 ↦ x1 < x2) j i
⊢ a₂ j = Function.update a₂ i a j

Tactic:
dsimp only at hj

Goal state after:
case refine_1
ι : Type u_1
β : ι → Type u_2
r : ι → ι → Prop
s : {i : ι} → β i → β i → Prop
inst✝² : Preorder ι
inst✝¹ : (i : ι) → LT (β i)
inst✝ : ∀ (i : ι), DenselyOrdered (β i)
a₁✝ a₂ : Lex ((i : ι) → β i)
i : ι
h : ∀ (j : ι), (fun x1 x2 ↦ x1 < x2) j i → a₁✝ j = a₂ j
hi : a₁✝ i < a₂ i
a : β i
ha₁ : a₁✝ i < a
ha₂ : a < a₂ i
j : ι
hj : j < i
⊢ a₂ j = Function.update a₂ i a j
Module: Mathlib.Data.DFinsupp.Order

Goal state before:
pp: ι : Type u_1
α : ι → Type u_2
inst✝³ : (i : ι) → Zero (α i)
inst✝² : (i : ι) → Lattice (α i)
f g : Π₀ (i : ι), α i
inst✝¹ : DecidableEq ι
inst✝ : (i : ι) → (x : α i) → Decidable (x ≠ 0)
x✝ : ι
⊢ x✝ ∈ (↑((f ⊓ g).support ∪ (f ⊔ g).support))ᶜ ↔ x✝ ∈ (↑(f.support ∪ g.support))ᶜ

Tactic:
simp [inf_eq_and_sup_eq_iff]

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

Goal state before:
pp: case neg
S : Type v
inst✝ : CommRing S
z p : S
f : S[X]
i : ℕ
dvd_eval : p ∣ eval z f
dvd_terms : ∀ (j : ℕ), j ≠ i → p ∣ f.coeff j * z ^ j
hi : i ∉ f.support
⊢ p ∣ f.coeff i * z ^ i

Tactic:
convert! dvd_zero p
    rw [notMem_support_iff] at hi
    simp [hi]

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

Goal state before:
pp: case monomial
R : Type u
A : Type z
M : Type u_3
inst✝⁶ : CommSemiring R
inst✝⁵ : AddCommMonoid M
inst✝⁴ : Module R M
q : Submodule R M
m : M
inst✝³ : Semiring A
inst✝² : Algebra R A
inst✝¹ : Module A M
inst✝ : IsScalarTower R A M
hm : m ∈ q
a : A
hq : q ≤ Submodule.comap ((Algebra.lsmul R R M) a) q
n : ℕ
t : R
hmq : (aeval a) (C t * X ^ n) • m ∈ q
⊢ a • (aeval a) (C t * X ^ n) • m ∈ q

Tactic:
solve_by_elim

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

Goal state before:
pp: R : Type u
σ : Type u_1
inst✝ : CommSemiring R
m : σ →₀ ℕ
a : R
ha : IsRegular a
p q : MvPolynomial σ R
h : (fun x ↦ (MvPolynomial.monomial m) a * x) p = (fun x ↦ (MvPolynomial.monomial m) a * x) q
d : σ →₀ ℕ
h' :
  coeff (m + d) ((fun x ↦ (MvPolynomial.monomial m) a * x) p) =
    coeff (m + d) ((fun x ↦ (MvPolynomial.monomial m) a * x) q)
⊢ coeff d p = coeff d q

Tactic:
simp only [coeff_monomial_mul] at h'

Goal state after:
R : Type u
σ : Type u_1
inst✝ : CommSemiring R
m : σ →₀ ℕ
a : R
ha : IsRegular a
p q : MvPolynomial σ R
h : (fun x ↦ (MvPolynomial.monomial m) a * x) p = (fun x ↦ (MvPolynomial.monomial m) a * x) q
d : σ →₀ ℕ
h' : a * coeff d p = a * coeff d q
⊢ coeff d p = coeff d q
Module: Mathlib.Data.DFinsupp.Lex

Goal state before:
pp: ι : Type u_1
α : ι → Type u_2
inst✝³ : LinearOrder ι
inst✝² : (i : ι) → AddMonoid (α i)
inst✝¹ : (i : ι) → LinearOrder (α i)
inst✝ : ∀ (i : ι), AddLeftStrictMono (α i)
x✝³ x✝² x✝¹ : Lex (Π₀ (i : ι), α i)
x✝ : x✝² < x✝¹
a : ι
lta : ∀ (j : ι), (fun x1 x2 ↦ x1 < x2) j a → (ofLex x✝²) j = (ofLex x✝¹) j
ha : (fun {i} ↦ (fun x x1 x2 ↦ x1 < x2) i) ((ofLex x✝²) a) ((ofLex x✝¹) a)
⊢ (ofLex x✝³) a + (ofLex x✝²) a < (ofLex x✝³) a + (ofLex x✝¹) a

Tactic:
gcongr

Goal state after:
Module: Mathlib.Data.DFinsupp.Lex

Goal state before:
pp: ι : Type u_1
α : ι → Type u_2
inst✝³ : LinearOrder ι
inst✝² : (i : ι) → AddMonoid (α i)
inst✝¹ : (i : ι) → LinearOrder (α i)
inst✝ : ∀ (i : ι), AddRightStrictMono (α i)
f x✝² x✝¹ : Lex (Π₀ (i : ι), α i)
x✝ : x✝² < x✝¹
a : ι
lta : ∀ (j : ι), (fun x1 x2 ↦ x1 < x2) j a → (ofLex x✝²) j = (ofLex x✝¹) j
ha : (fun {i} ↦ (fun x x1 x2 ↦ x1 < x2) i) ((ofLex x✝²) a) ((ofLex x✝¹) a)
⊢ (ofLex x✝²) a + (ofLex f) a < (ofLex x✝¹) a + (ofLex f) a

Tactic:
gcongr

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

Goal state before:
pp: R : Type u
σ : Type u_1
inst✝¹ : CommSemiring R
inst✝ : DecidableEq R
p q : MvPolynomial σ R
h : Disjoint p.support q.support
r : R
⊢ r ∈ (p + q).coeffs ↔ r ∈ p.coeffs ∪ q.coeffs

Tactic:
simp only [mem_coeffs_iff, mem_support_iff, coeff_add, ne_eq, Finset.mem_union]

Goal state after:
R : Type u
σ : Type u_1
inst✝¹ : CommSemiring R
inst✝ : DecidableEq R
p q : MvPolynomial σ R
h : Disjoint p.support q.support
r : R
⊢ (∃ n, ¬coeff n p + coeff n q = 0 ∧ r = coeff n p + coeff n q) ↔
    (∃ n, ¬coeff n p = 0 ∧ r = coeff n p) ∨ ∃ n, ¬coeff n q = 0 ∧ r = coeff n q
Module: Mathlib.Algebra.MvPolynomial.Degrees

Goal state before:
pp: case inr
R : Type u
σ : Type u_1
inst✝ : CommSemiring R
p q : MvPolynomial σ R
h : ∀ a ∈ p.degrees, ∀ b ∈ q.degrees, a ≠ b
d : σ →₀ ℕ
hd : d ∈ p.support
h0 : d ≠ 0
⊢ coeff d q = 0

Tactic:
rw [Ne, ← Finsupp.support_eq_empty, ← Ne, ← Finset.nonempty_iff_ne_empty] at h0

Goal state after:
case inr
R : Type u
σ : Type u_1
inst✝ : CommSemiring R
p q : MvPolynomial σ R
h : ∀ a ∈ p.degrees, ∀ b ∈ q.degrees, a ≠ b
d : σ →₀ ℕ
hd : d ∈ p.support
h0 : d.support.Nonempty
⊢ coeff d q = 0
Module: Mathlib.Algebra.MvPolynomial.Eval

Goal state before:
pp: R : Type u
S₁ : Type v
σ : Type u_1
inst✝¹ : CommSemiring R
inst✝ : CommSemiring S₁
f : R →+* S₁
x : MvPolynomial σ S₁
⊢ x ∈ range ⇑(map f) ↔ ↑x.coeffs ⊆ range ⇑f

Tactic:
refine ⟨fun hx ↦ ?_, fun hx ↦ ?_⟩

Goal state after:
case refine_1
R : Type u
S₁ : Type v
σ : Type u_1
inst✝¹ : CommSemiring R
inst✝ : CommSemiring S₁
f : R →+* S₁
x : MvPolynomial σ S₁
hx : x ∈ range ⇑(map f)
⊢ ↑x.coeffs ⊆ range ⇑f

case refine_2
R : Type u
S₁ : Type v
σ : Type u_1
inst✝¹ : CommSemiring R
inst✝ : CommSemiring S₁
f : R →+* S₁
x : MvPolynomial σ S₁
hx : ↑x.coeffs ⊆ range ⇑f
⊢ x ∈ range ⇑(map f)
Module: Mathlib.Algebra.MvPolynomial.Variables

Goal state before:
pp: R : Type u
σ : Type u_1
inst✝¹ : CommSemiring R
ι : Type u_3
t : Finset ι
φ : ι → MvPolynomial σ R
inst✝ : DecidableEq σ
⊢ (∑ i ∈ t, φ i).vars ⊆ t.biUnion fun i ↦ (φ i).vars

Tactic:
classical
  induction t using Finset.induction_on with
  | empty => simp
  | insert _ _ has hsum =>
    rw [Finset.biUnion_insert, Finset.sum_insert has]
    refine Finset.Subset.trans
      (vars_add_subset _ _) (Finset.union_subset_union (Finset.Subset.refl _) ?_)
    assumption

Goal state after:
Module: Mathlib.Data.Finsupp.Fin

Goal state before:
pp: n : ℕ
i : Fin n
M : Type u_1
inst✝ : Zero M
y : M
s : Fin n →₀ M
x : M
⊢ cons x s = single i.succ y ↔ s = single i y ∧ x = 0

Tactic:
← cons_zero_single_eq_single_succ,

Goal state after:
n : ℕ
i : Fin n
M : Type u_1
inst✝ : Zero M
y : M
s : Fin n →₀ M
x : M
⊢ cons x s = cons 0 (single i y) ↔ s = single i y ∧ x = 0
Module: Mathlib.Algebra.MvPolynomial.Degrees

Goal state before:
pp: R : Type u
σ : Type u_1
inst✝¹ : CommSemiring R
inst✝ : Fintype σ
f : MvPolynomial σ R
n : ℕ
d : σ →₀ ℕ
hd : d ∈ f.support
h : ∀ (i : σ), n ≤ d i
⊢ n * Fintype.card σ = ∑ _s, n

Tactic:
rw [Finset.sum_const, Nat.nsmul_eq_mul, mul_comm, Finset.card_univ]

Goal state after:
Module: Mathlib.Algebra.Polynomial.Degree.Lemmas

Goal state before:
pp: R : Type u
inst✝ : Semiring R
p q : R[X]
this : DecidableEq R := Classical.decEq R
h0 : ¬p.comp q = 0
n : ℕ
hn : n ∈ p.support
⊢ ↑(n * q.natDegree) ≤ ↑(p.natDegree * q.natDegree)

Tactic:
gcongr

Goal state after:
case h₁
R : Type u
inst✝ : Semiring R
p q : R[X]
this : DecidableEq R := ⋯
h0 : ¬p.comp q = 0
n : ℕ
hn : n ∈ p.support
⊢ n ≤ p.natDegree
Module: Mathlib.Algebra.Polynomial.Degree.Lemmas

Goal state before:
pp: R : Type u
a : R
inst✝ : Semiring R
p : R[X]
hp : p ≠ 0
h : p.IsRoot a
hlt : p.degree ≤ 0
⊢ False

Tactic:
by
    have := eq_C_of_degree_le_zero hlt
    rw [IsRoot, this, eval_C] at h
    simp only [h, map_zero] at this
    exact hp this

Goal state after:
Module: Mathlib.Algebra.Polynomial.Degree.TrailingDegree

Goal state before:
pp: case a
R : Type u
inst✝ : Semiring R
p : R[X]
hp : p ≠ 0
n y : ℕ
hy : (p * X ^ n).coeff y ≠ 0
key : n ≤ y
⊢ p.natTrailingDegree + n ≤ y

Tactic:
coeff_mul_X_pow',

Goal state after:
case a
R : Type u
inst✝ : Semiring R
p : R[X]
hp : p ≠ 0
n y : ℕ
hy : (if n ≤ y then p.coeff (y - n) else 0) ≠ 0
key : n ≤ y
⊢ p.natTrailingDegree + n ≤ y
Module: Mathlib.Algebra.Polynomial.Degree.TrailingDegree

Goal state before:
pp: case a
R : Type u
inst✝ : Semiring R
p : R[X]
hp : p ≠ 0
n y : ℕ
hy : (if n ≤ y then p.coeff (y - n) else 0) ≠ 0
key : n ≤ y
⊢ p.natTrailingDegree + n ≤ y

Tactic:
if_pos key

Goal state after:
case a
R : Type u
inst✝ : Semiring R
p : R[X]
hp : p ≠ 0
n y : ℕ
hy : p.coeff (y - n) ≠ 0
key : n ≤ y
⊢ p.natTrailingDegree + n ≤ y
Module: Mathlib.Algebra.Polynomial.Degree.Lemmas

Goal state before:
pp: R : Type u
m✝ n : ℕ
inst✝ : Semiring R
p : R[X]
pn : p.natDegree ≤ n
m : ℕ
hm : (p ^ m).coeff (m * n) = p.coeff n ^ m
⊢ m * p.natDegree ≤ m * n

Tactic:
gcongr

Goal state after:
Module: Mathlib.Algebra.Polynomial.Degree.Lemmas

Goal state before:
pp: case succ
R : Type u
m✝ n : ℕ
inst✝ : Semiring R
p : R[X]
pn : p.natDegree ≤ n
m : ℕ
hm : (p ^ m).coeff (m * n) = p.coeff n ^ m
⊢ (p ^ (m + 1)).coeff ((m + 1) * n) = p.coeff n ^ (m + 1)

Tactic:
| succ m hm =>

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

Goal state before:
pp: R : Type u
S₁ : Type v
S₂ : Type w
S₃ : Type x
σ✝ : Type u_1
a a' a₁ a₂ : R
e : ℕ
s : σ✝ →₀ ℕ
inst✝¹ : CommSemiring R
σ : Type u_2
inst✝ : Unique σ
p✝ : R[X]
p : ℕ
n : R
x✝ :
  eval₂ Polynomial.C (fun x ↦ Polynomial.X) (Polynomial.eval₂ C (X default) (Polynomial.C n * Polynomial.X ^ p)) =
    Polynomial.C n * Polynomial.X ^ p
⊢ eval₂ Polynomial.C (fun x ↦ Polynomial.X) (Polynomial.eval₂ C (X default) (Polynomial.C n * Polynomial.X ^ (p + 1))) =
    Polynomial.C n * Polynomial.X ^ (p + 1)

Tactic:
by
      rw [Polynomial.eval₂_mul, Polynomial.eval₂_pow, Polynomial.eval₂_X, Polynomial.eval₂_C,
        eval₂_mul, eval₂_C, eval₂_pow, eval₂_X]

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

Goal state before:
pp: case neg.Cg
R : Type u_1
inst✝ : Semiring R
N O : ℕ
f : R[X]
Cf : #f.support ≤ Nat.succ 0
Nf : f.natDegree ≤ N
cg : ℕ
hcg : ∀ (g : R[X]), #g.support ≤ cg.succ → g.natDegree ≤ O → reflect (N + O) (f * g) = reflect N f * reflect O g
g : R[X]
Cg : #g.support ≤ (cg + 1).succ
Og : g.natDegree ≤ O
g0 : ¬g = 0
⊢ #(C g.leadingCoeff * X ^ g.natDegree).support ≤ cg.succ

Tactic:
exact le_add_left card_support_C_mul_X_pow_le_one

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

Goal state before:
pp: case neg.Og
R : Type u_1
inst✝ : Semiring R
N O : ℕ
f : R[X]
Cf : #f.support ≤ Nat.succ 0
Nf : f.natDegree ≤ N
cg : ℕ
hcg : ∀ (g : R[X]), #g.support ≤ cg.succ → g.natDegree ≤ O → reflect (N + O) (f * g) = reflect N f * reflect O g
g : R[X]
Cg : #g.support ≤ (cg + 1).succ
Og : g.natDegree ≤ O
g0 : ¬g = 0
⊢ g.eraseLead.natDegree ≤ O

Tactic:
· exact le_trans eraseLead_natDegree_le_aux Og

Goal state after:
Module: Mathlib.Algebra.Polynomial.Degree.Lemmas

Goal state before:
pp: R : Type u
S : Type v
inst✝¹ : Semiring R
inst✝ : Semiring S
f : R →+* S
hf : Function.Injective ⇑f
p : R[X]
⊢ (map f p).nextCoeff = f p.nextCoeff

Tactic:
by
  simp only [hf, nextCoeff, natDegree_map_eq_of_injective]
  split_ifs <;> simp

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

Goal state before:
pp: case neg.Cf
R : Type u_1
inst✝ : Semiring R
cg N O : ℕ
g : R[X]
Cg : #g.support ≤ cg.succ
Og : g.natDegree ≤ O
cf : ℕ
hcf : ∀ (f : R[X]), #f.support ≤ cf.succ → f.natDegree ≤ N → reflect (N + O) (f * g) = reflect N f * reflect O g
f : R[X]
Cf : #f.support ≤ (cf + 1).succ
Nf : f.natDegree ≤ N
f0 : ¬f = 0
⊢ #(C f.leadingCoeff * X ^ f.natDegree).support ≤ cf.succ

Tactic:
exact le_add_left card_support_C_mul_X_pow_le_one

Goal state after:
Module: Mathlib.Algebra.Polynomial.Degree.Lemmas

Goal state before:
pp: case inl
R : Type u
inst✝¹ : Semiring R
inst✝ : NoZeroDivisors R
p q : R[X]
h : p.comp q = 0
key✝ : p.natDegree = 0 ∨ q.natDegree = 0
key : p = C (p.coeff 0)
⊢ p = 0 ∨ eval (q.coeff 0) p = 0 ∧ q = C (q.coeff 0)

pp: case inr
R : Type u
inst✝¹ : Semiring R
inst✝ : NoZeroDivisors R
p q : R[X]
h : p.comp q = 0
key✝ : p.natDegree = 0 ∨ q.natDegree = 0
key : q = C (q.coeff 0)
⊢ p = 0 ∨ eval (q.coeff 0) p = 0 ∧ q = C (q.coeff 0)

Tactic:
· rw [key, C_comp] at h
    exact Or.inl (key.trans h)

Goal state after:
case inr
R : Type u
inst✝¹ : Semiring R
inst✝ : NoZeroDivisors R
p q : R[X]
h : p.comp q = 0
key✝ : p.natDegree = 0 ∨ q.natDegree = 0
key : q = C (q.coeff 0)
⊢ p = 0 ∨ eval (q.coeff 0) p = 0 ∧ q = C (q.coeff 0)
Module: Mathlib.Algebra.MvPolynomial.Equiv

Goal state before:
pp: R : Type u
S₁ : Type v
inst✝ : CommSemiring R
p : MvPolynomial (Option S₁) R
i : ℕ
hi : i ≤ p.totalDegree
hpi : ¬((optionEquivLeft R S₁) p).coeff i = 0
⊢ (((optionEquivLeft R S₁) p).coeff i).support.Nonempty

Tactic:
simpa only [support_nonempty]

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

Goal state before:
pp: R : Type u
S₁ : Type v
S₂ : Type w
S₃ : Type x
σ : Type u_1
a a' a₁ a₂ : R
e : ℕ
s : σ →₀ ℕ
inst✝ : CommSemiring R
⊢ (aeval fun o ↦ o.elim (C Polynomial.X) X).comp (aevalTower (Polynomial.aeval (X none)) fun i ↦ X (Option.some i)) =
    AlgHom.id R (MvPolynomial S₁ R[X])

Tactic:
ext : 2 <;>
        simp only [MvPolynomial.algebraMap_eq, Option.elim, AlgHom.coe_comp, AlgHom.id_comp,
          IsScalarTower.coe_toAlgHom', comp_apply, aevalTower_C, Polynomial.aeval_X, aeval_X,
          aevalTower_X, AlgHom.coe_id, id]

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

Goal state before:
pp: case pos
R : Type u_1
inst✝ : Semiring R
f : R[X]
hf : f = 0
⊢ f.natDegree = f.reverse.natDegree + f.natTrailingDegree

Tactic:
rw [hf, reverse_zero, natDegree_zero, natTrailingDegree_zero]

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

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

Tactic:
commute_X p,

Goal state after:
R : Type u_1
inst✝ : Semiring R
p : R[X]
⊢ (p * X).reverse = p.reverse
Module: Mathlib.Algebra.Polynomial.Monic

Goal state before:
pp: case refine_2
R : Type u
ι : Type y
inst✝ : CommSemiring R
t✝ : Multiset ι
f : ι → R[X]
a : ι
t : Multiset ι
ih : (∀ i ∈ t, (f i).Monic) → (Multiset.map f t).prod.nextCoeff = (Multiset.map (fun i ↦ (f i).nextCoeff) t).sum
ht : ∀ i ∈ a ::ₘ t, (f i).Monic
⊢ (f a ::ₘ Multiset.map f t).prod.nextCoeff = (Multiset.map (fun i ↦ (f i).nextCoeff) (a ::ₘ t)).sum

Tactic:
Multiset.prod_cons,

Goal state after:
case refine_2
R : Type u
ι : Type y
inst✝ : CommSemiring R
t✝ : Multiset ι
f : ι → R[X]
a : ι
t : Multiset ι
ih : (∀ i ∈ t, (f i).Monic) → (Multiset.map f t).prod.nextCoeff = (Multiset.map (fun i ↦ (f i).nextCoeff) t).sum
ht : ∀ i ∈ a ::ₘ t, (f i).Monic
⊢ (f a * (Multiset.map f t).prod).nextCoeff = (Multiset.map (fun i ↦ (f i).nextCoeff) (a ::ₘ t)).sum
Module: Mathlib.Algebra.Polynomial.Monic

Goal state before:
pp: 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.natDegree ≠ 0 ∧ g.natDegree ≠ 0
hl : f.natDegree ≤ g.natDegree
⊢ f.natDegree + f.natDegree ≤ f.natDegree + g.natDegree

Tactic:
gcongr

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

Goal state before:
pp: case refine_2
R : Type u
inst✝ : CommSemiring R
t✝ : Multiset R[X]
a : R[X]
t : Multiset R[X]
ht : t.prod.coeff 0 = (Multiset.map (fun f ↦ f.coeff 0) t).prod
⊢ (a ::ₘ t).prod.coeff 0 = (Multiset.map (fun f ↦ f.coeff 0) (a ::ₘ t)).prod

Tactic:
Multiset.prod_cons,

Goal state after:
case refine_2
R : Type u
inst✝ : CommSemiring R
t✝ : Multiset R[X]
a : R[X]
t : Multiset R[X]
ht : t.prod.coeff 0 = (Multiset.map (fun f ↦ f.coeff 0) t).prod
⊢ (a * t.prod).coeff 0 = (Multiset.map (fun f ↦ f.coeff 0) (a ::ₘ t)).prod
Module: Mathlib.Algebra.Polynomial.Monic

Goal state before:
pp: 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.natDegree ≠ 0 ∧ g.natDegree ≠ 0
hl : g.natDegree ≤ f.natDegree
⊢ g.natDegree + g.natDegree ≤ f.natDegree + g.natDegree

Tactic:
gcongr

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

Goal state before:
pp: case refine_2
R : Type u
inst✝ : CommSemiring R
t✝ : Multiset R[X]
a : R[X]
t : Multiset R[X]
ht : t.prod.coeff 0 = (Multiset.map (fun f ↦ f.coeff 0) t).prod
⊢ (a * t.prod).coeff 0 = (a.coeff 0 ::ₘ Multiset.map (fun f ↦ f.coeff 0) t).prod

Tactic:
Multiset.prod_cons,

Goal state after:
case refine_2
R : Type u
inst✝ : CommSemiring R
t✝ : Multiset R[X]
a : R[X]
t : Multiset R[X]
ht : t.prod.coeff 0 = (Multiset.map (fun f ↦ f.coeff 0) t).prod
⊢ (a * t.prod).coeff 0 = a.coeff 0 * (Multiset.map (fun f ↦ f.coeff 0) t).prod
Module: Mathlib.Algebra.Ring.GeomSum

Goal state before:
pp: R : Type u_1
inst✝ : Semiring R
x y : R
h : Commute x y
f : ℕ → ℕ → R := fun m i ↦ (x + y) ^ i * y ^ (m - 1 - i)
n : ℕ
ih : (∑ i ∈ range n, f n i) * x + y ^ n = (x + y) ^ n
f_last : f (n + 1) n = (x + y) ^ n
i : ℕ
hi : i ∈ range n
this : Commute y ((x + y) ^ i)
⊢ (x + y) ^ i * y ^ (n + 1 - 1 - i) = (x + y) ^ i * (y * y ^ (n - 1 - i))

Tactic:
← pow_succ' y (n - 1 - i),

Goal state after:
R : Type u_1
inst✝ : Semiring R
x y : R
h : Commute x y
f : ℕ → ℕ → R := fun m i ↦ (x + y) ^ i * y ^ (m - 1 - i)
n : ℕ
ih : (∑ i ∈ range n, f n i) * x + y ^ n = (x + y) ^ n
f_last : f (n + 1) n = (x + y) ^ n
i : ℕ
hi : i ∈ range n
this : Commute y ((x + y) ^ i)
⊢ (x + y) ^ i * y ^ (n + 1 - 1 - i) = (x + y) ^ i * y ^ (n - 1 - i + 1)
Module: Mathlib.Algebra.Polynomial.Monic

Goal state before:
pp: case inl
R : Type u_1
inst✝¹ : Ring R
inst✝ : Nontrivial R
h : IsUnit (X ^ 0 - 1)
⊢ False

pp: case inr
R : Type u_1
inst✝¹ : Ring R
inst✝ : Nontrivial R
n : ℕ
h : IsUnit (X ^ n - 1)
hn : n ≠ 0
⊢ False

Tactic:
· simp at h

Goal state after:
case inr
R : Type u_1
inst✝¹ : Ring R
inst✝ : Nontrivial R
n : ℕ
h : IsUnit (X ^ n - 1)
hn : n ≠ 0
⊢ False
Module: Mathlib.RingTheory.Polynomial.Basic

Goal state before:
pp: R : Type u
inst✝ : Semiring R
s : Set R[X]
s_fin : s.Finite
⊢ ∃ n, Submodule.span R s ≤ degreeLE R ↑n

Tactic:
by_cases s_emp : s.Nonempty
  · rcases exists_degree_le_of_mem_span_of_finite s_fin s_emp with ⟨p', _, hp'max⟩
    exact ⟨natDegree p', fun p hp => mem_degreeLE.mpr ((hp'max _ hp).trans degree_le_natDegree)⟩
  · rw [Set.not_nonempty_iff_eq_empty] at s_emp
    rw [s_emp, Submodule.span_empty]
    exact ⟨0, bot_le⟩

Goal state after:
Module: Mathlib.Algebra.Ring.GeomSum

Goal state before:
pp: m k x y : ℕ
hmk : m ∣ k
⊢ x ^ m - y ^ m ∣ x ^ k - y ^ k

Tactic:
obtain ⟨n, rfl⟩ := hmk; simpa [pow_mul] using (x ^ m).sub_dvd_pow_sub_pow (y ^ m) n

Goal state after: