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

Goal state before:
pp: R S : Type u
inst✝¹ : Semiring R
inst✝ : Semiring S
f : R →+* S
I : Ideal R
⊢ Submodule.spanRank (map f I) ≤ Submodule.spanRank I

Tactic:
simpa using

Goal state after:
R S : Type u
inst✝¹ : Semiring R
inst✝ : Semiring S
f : R →+* S
I : Ideal R
⊢ Submodule.spanRank (map f I) ≤ Submodule.spanRank I
Module: Mathlib.Algebra.Module.SpanRank

Goal state before:
pp: R S : Type u
inst✝¹ : Semiring R
inst✝ : Semiring S
f : R ≃+* S
I : Ideal R
⊢ Submodule.spanRank (map f I) = Submodule.spanRank I

Tactic:
simpa using

Goal state after:
R S : Type u
inst✝¹ : Semiring R
inst✝ : Semiring S
f : R ≃+* S
I : Ideal R
⊢ Submodule.spanRank (map f I) = Submodule.spanRank I
Module: Mathlib.RingTheory.IntegralClosure.IsIntegral.Basic

Goal state before:
pp: R : Type u_1
inst✝⁴ : CommRing R
A : Type u_5
B : Type u_6
inst✝³ : Ring A
inst✝² : Ring B
inst✝¹ : Algebra R A
inst✝ : Algebra R B
f : A ≃ₐ[R] B
x : A
h : IsIntegral R (f x)
⊢ IsIntegral R x

Tactic:
simpa using

Goal state after:
R : Type u_1
inst✝⁴ : CommRing R
A : Type u_5
B : Type u_6
inst✝³ : Ring A
inst✝² : Ring B
inst✝¹ : Algebra R A
inst✝ : Algebra R B
f : A ≃ₐ[R] B
x : A
h : IsIntegral R (f x)
⊢ IsIntegral R x
Module: Mathlib.LinearAlgebra.Matrix.Charpoly.Coeff

Goal state before:
pp: case succ.h₀.succ
R : Type u
inst✝ : CommRing R
n : ℕ
IH : ∀ (M : Matrix (Fin (n + 1)) (Fin (n + 1)) R), eval 0 (derivative (1 + X • M.map ⇑C).det) = M.trace
M : Matrix (Fin (n + 1 + 1)) (Fin (n + 1 + 1)) R
i : Fin (n + 1).succ
a✝ : i ∈ univ
hi : i ≠ 0
j : Fin (n + 1)
⊢ j.succ ≠ Fin.castSucc 0

pp: case succ.h₀.succ.h
R : Type u
inst✝ : CommRing R
n : ℕ
IH : ∀ (M : Matrix (Fin (n + 1)) (Fin (n + 1)) R), eval 0 (derivative (1 + X • M.map ⇑C).det) = M.trace
M : Matrix (Fin (n + 1 + 1)) (Fin (n + 1 + 1)) R
i : Fin (n + 1).succ
a✝ : i ∈ univ
hi : i ≠ 0
j : Fin (n + 1)
⊢ Fin.castSucc 0 < i

Tactic:
· exact (bne_iff_ne (a := Fin.succ j) (b := Fin.castSucc 0)).mp rfl

Goal state after:
case succ.h₀.succ.h
R : Type u
inst✝ : CommRing R
n : ℕ
IH : ∀ (M : Matrix (Fin (n + 1)) (Fin (n + 1)) R), eval 0 (derivative (1 + X • M.map ⇑C).det) = M.trace
M : Matrix (Fin (n + 1 + 1)) (Fin (n + 1 + 1)) R
i : Fin (n + 1).succ
a✝ : i ∈ univ
hi : i ≠ 0
j : Fin (n + 1)
⊢ Fin.castSucc 0 < i
Module: Mathlib.LinearAlgebra.Matrix.Charpoly.Coeff

Goal state before:
pp: case succ.h₀.succ.h
R : Type u
inst✝ : CommRing R
n : ℕ
IH : ∀ (M : Matrix (Fin (n + 1)) (Fin (n + 1)) R), eval 0 (derivative (1 + X • M.map ⇑C).det) = M.trace
M : Matrix (Fin (n + 1 + 1)) (Fin (n + 1 + 1)) R
i : Fin (n + 1).succ
a✝ : i ∈ univ
hi : i ≠ 0
j : Fin (n + 1)
⊢ 0 < i

Tactic:
exact lt_of_le_of_ne (Fin.zero_le _) hi.symm

Goal state after:
Module: Mathlib.LinearAlgebra.Matrix.Charpoly.Coeff

Goal state before:
pp: R : Type u
inst✝² : CommRing R
n : Type v
inst✝¹ : DecidableEq n
inst✝ : Fintype n
r : R
M : Matrix n n R
⊢ (1 + r • M).det = 1 + M.trace * r + eval r (1 + X • M.map ⇑C).det.divX.divX * r ^ 2

Tactic:
simpa using

Goal state after:
R : Type u
inst✝² : CommRing R
n : Type v
inst✝¹ : DecidableEq n
inst✝ : Fintype n
r : R
M : Matrix n n R
⊢ (1 + r • M).det = 1 + M.trace * r + eval r (1 + X • M.map ⇑C).det.divX.divX * r ^ 2
Module: Mathlib.LinearAlgebra.Matrix.Charpoly.Coeff

Goal state before:
pp: case pos.«_@».Mathlib.LinearAlgebra.Matrix.Charpoly.Coeff.4094078725._hygCtx._hyg.105.«2»
R : Type u
inst✝³ : CommRing R
n : Type v
inst✝² : DecidableEq n
inst✝¹ : Fintype n
M : Matrix n n R
inst✝ : Nontrivial R
hn : Fintype.card n = 2
this : Nonempty n
⊢ M.charpoly.coeff 2 = (X ^ 2 - C M.trace * X + C M.det).coeff 2

Tactic:
simpa using

Goal state after:
case pos.«_@».Mathlib.LinearAlgebra.Matrix.Charpoly.Coeff.4094078725._hygCtx._hyg.105.«2»
R : Type u
inst✝³ : CommRing R
n : Type v
inst✝² : DecidableEq n
inst✝¹ : Fintype n
M : Matrix n n R
inst✝ : Nontrivial R
hn : Fintype.card n = 2
this : Nonempty n
⊢ M.charpoly.coeff 2 = 1
Module: Mathlib.LinearAlgebra.Matrix.Charpoly.Coeff

Goal state before:
pp: case neg
R : Type u
inst✝³ : CommRing R
n : Type v
inst✝² : DecidableEq n
inst✝¹ : Fintype n
M : Matrix n n R
inst✝ : Nontrivial R
hn : Fintype.card n = 2
this : Nonempty n
i : ℕ
hi : 2 < i
⊢ M.charpoly.natDegree < i

Tactic:
simpa using

Goal state after:
case neg
R : Type u
inst✝³ : CommRing R
n : Type v
inst✝² : DecidableEq n
inst✝¹ : Fintype n
M : Matrix n n R
inst✝ : Nontrivial R
hn : Fintype.card n = 2
this : Nonempty n
i : ℕ
hi : 2 < i
⊢ 2 < i
Module: Mathlib.RingTheory.IntegralClosure.Algebra.Basic

Goal state before:
pp: R : Type u_1
S : Type u_4
inst✝¹ : CommRing R
inst✝ : CommRing S
f : R →+* S
x y : S
hx : f.IsIntegralElem x
hy : f.IsIntegralElem y
⊢ f.IsIntegralElem (x - y)

Tactic:
simpa using

Goal state after:
R : Type u_1
S : Type u_4
inst✝¹ : CommRing R
inst✝ : CommRing S
f : R →+* S
x y : S
hx : f.IsIntegralElem x
hy : f.IsIntegralElem y
⊢ f.IsIntegralElem (x + -y)
Module: Mathlib.LinearAlgebra.Matrix.Charpoly.Coeff

Goal state before:
pp: R : Type u
inst✝² : CommRing R
n : Type v
inst✝¹ : DecidableEq n
inst✝ : Fintype n
M : Matrix n n R
hM : IsNilpotent M
h✝ : Nonempty n
this : IsNilpotent (M.charpolyRev.coeff 1)
⊢ IsNilpotent M.trace

Tactic:
simpa using

Goal state after:
R : Type u
inst✝² : CommRing R
n : Type v
inst✝¹ : DecidableEq n
inst✝ : Fintype n
M : Matrix n n R
hM : IsNilpotent M
h✝ : Nonempty n
this : IsNilpotent (M.charpolyRev.coeff 1)
⊢ IsNilpotent M.trace
Module: Mathlib.Algebra.Polynomial.HasseDeriv

Goal state before:
pp: case succ.e_a.e_a.e_a
R : Type u_1
inst✝ : Semiring R
k✝ k : ℕ
ih : ⇑(k ! • hasseDeriv k) = (⇑derivative)^[k]
f : R[X]
n : ℕ
this : n + k + 1 = n + (k + 1)
⊢ k + 1 = n + (k + 1) - n

Tactic:
add_tsub_cancel_left

Goal state after:
case succ.e_a.e_a.e_a
R : Type u_1
inst✝ : Semiring R
k✝ k : ℕ
ih : ⇑(k ! • hasseDeriv k) = (⇑derivative)^[k]
f : R[X]
n : ℕ
this : n + k + 1 = n + (k + 1)
⊢ k + 1 = k + 1
Module: Mathlib.Algebra.Polynomial.HasseDeriv

Goal state before:
pp: case neg
R : Type u_1
inst✝ : Semiring R
k l i : ℕ
hikl : k + l ≤ i
h1 : l ≤ i
h2 : k ≤ i - l
h3 : k ≤ k + l
⊢ ↑(i - l)! / (↑k ! * ↑(i - l - k)!) * (↑i ! / (↑l ! * ↑(i - l)!)) =
    ↑(k + l)! / (↑k ! * ↑(k + l - k)!) * (↑i ! / (↑(k + l)! * ↑(i - (k + l))!))

Tactic:
show i - (k + l) = i - l - k by rw [add_comm]; apply tsub_add_eq_tsub_tsub

Goal state after:
case neg
R : Type u_1
inst✝ : Semiring R
k l i : ℕ
hikl : k + l ≤ i
h1 : l ≤ i
h2 : k ≤ i - l
h3 : k ≤ k + l
⊢ ↑(i - l)! / (↑k ! * ↑(i - l - k)!) * (↑i ! / (↑l ! * ↑(i - l)!)) =
    ↑(k + l)! / (↑k ! * ↑(k + l - k)!) * (↑i ! / (↑(k + l)! * ↑(i - l - k)!))
Module: Mathlib.RingTheory.Polynomial.ScaleRoots

Goal state before:
pp: R : Type u_1
inst✝ : Semiring R
p : R[X]
s : R
x✝ : ℕ
⊢ x✝ ∈ (p.scaleRoots s).support → x✝ ∈ p.support

Tactic:
simpa using

Goal state after:
R : Type u_1
inst✝ : Semiring R
p : R[X]
s : R
x✝ : ℕ
⊢ ¬p.coeff x✝ * s ^ (p.natDegree - x✝) = 0 → ¬p.coeff x✝ = 0
Module: Mathlib.LinearAlgebra.Matrix.Charpoly.Coeff

Goal state before:
pp: R : Type u
inst✝² : CommRing R
n : Type v
inst✝¹ : DecidableEq n
inst✝ : Fintype n
M : Matrix n n R
k : ℕ
hk : k ≤ Fintype.card n
a✝ : Nontrivial R
hnd : M.charpoly.natDegree = Fintype.card n
hrev : M.charpoly.coeff (Fintype.card n - k) = M.charpoly.reverse.coeff k
hcharpolyRev : M.charpolyRev = (1 + X • (-M).map ⇑C).det
s : Finset n
hs : s ∈ powersetCard k univ
⊢ (-1) ^ #s * (M.submatrix Subtype.val Subtype.val).det = (-1) ^ k * (M.submatrix Subtype.val Subtype.val).det

Tactic:
(Finset.mem_powersetCard.mp hs).2

Goal state after:
R : Type u
inst✝² : CommRing R
n : Type v
inst✝¹ : DecidableEq n
inst✝ : Fintype n
M : Matrix n n R
k : ℕ
hk : k ≤ Fintype.card n
a✝ : Nontrivial R
hnd : M.charpoly.natDegree = Fintype.card n
hrev : M.charpoly.coeff (Fintype.card n - k) = M.charpoly.reverse.coeff k
hcharpolyRev : M.charpolyRev = (1 + X • (-M).map ⇑C).det
s : Finset n
hs : s ∈ powersetCard k univ
⊢ (-1) ^ k * (M.submatrix Subtype.val Subtype.val).det = (-1) ^ k * (M.submatrix Subtype.val Subtype.val).det
Module: Mathlib.RingTheory.Polynomial.ScaleRoots

Goal state before:
pp: S : Type u_2
A : Type u_3
inst✝¹ : Semiring S
inst✝ : Semiring A
p : S[X]
f : S →+* A
a : A
s : S
hsa : Commute (f s) a
hf : ∀ (s₁ s₂ : S), Commute (f s₁) (f s₂)
i : ℕ
_hi : i ∈ p.support
hi' : i ∉ (p.scaleRoots s).support
⊢ p.coeff i * s ^ (p.natDegree - i) = 0

Tactic:
simpa using

Goal state after:
S : Type u_2
A : Type u_3
inst✝¹ : Semiring S
inst✝ : Semiring A
p : S[X]
f : S →+* A
a : A
s : S
hsa : Commute (f s) a
hf : ∀ (s₁ s₂ : S), Commute (f s₁) (f s₂)
i : ℕ
_hi : i ∈ p.support
hi' : i ∉ (p.scaleRoots s).support
⊢ p.coeff i * s ^ (p.natDegree - i) = 0
Module: Mathlib.RingTheory.Polynomial.ScaleRoots

Goal state before:
pp: R : Type u_1
inst✝ : CommSemiring R
p : R[X]
r s : R
⊢ p.scaleRoots (r * s) = (p.scaleRoots r).scaleRoots s

Tactic:
ext; simp [mul_pow, mul_assoc]

Goal state after:
Module: Mathlib.RingTheory.TensorProduct.MvPolynomial

Goal state before:
pp: R : Type u
N : Type v
inst✝⁵ : CommSemiring R
σ : Type u_1
S : Type u_3
inst✝⁴ : CommSemiring S
inst✝³ : Algebra R S
inst✝² : CommSemiring N
inst✝¹ : Algebra R N
inst✝ : DecidableEq σ
e : σ →₀ ℕ
s : S
n : N
d : σ →₀ ℕ
⊢ coeff d (rTensorAlgEquiv (s ⊗ₜ[R] (monomial e) n)) = if e = d then s ⊗ₜ[R] n else 0

Tactic:
simp [tmul_ite]

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

Goal state before:
pp: R : Type u_1
inst✝ : Semiring R
⊢ Splits 0

Tactic:
simpa using

Goal state after:
R : Type u_1
inst✝ : Semiring R
⊢ Splits 0
Module: Mathlib.Algebra.Polynomial.Splits

Goal state before:
pp: R : Type u_1
inst✝ : Semiring R
⊢ X.Splits

Tactic:
simpa using

Goal state after:
R : Type u_1
inst✝ : Semiring R
⊢ X.Splits
Module: Mathlib.RingTheory.Polynomial.Subring

Goal state before:
pp: R : Type u_1
inst✝ : Ring R
p : R[X]
T : Subring R
hp : ↑p.coeffs ⊆ ↑T
⊢ (p.toSubring T hp).support = p.support

Tactic:
ext i
  simp only [mem_support_iff, not_iff_not, Ne]
  conv_rhs => rw [← coeff_toSubring p T hp]
  exact ⟨fun H => by rw [H, ZeroMemClass.coe_zero], fun H => Subtype.coe_injective H⟩

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

Goal state before:
pp: R : Type u_1
inst✝ : Semiring R
a b : R
hf : (C a * X + C b).natDegree ≤ 1
h : Invertible (C a * X + C b).leadingCoeff
ha : a ≠ 0
⊢ Invertible a

Tactic:
simpa using

Goal state after:
R : Type u_1
inst✝ : Semiring R
a b : R
hf : (C a * X + C b).natDegree ≤ 1
h : Invertible (C a * X + C b).leadingCoeff
ha : a ≠ 0
⊢ Invertible a
Module: Mathlib.Algebra.Polynomial.Splits

Goal state before:
pp: R : Type u_1
inst✝ : CommSemiring R
p : R[X]
hp : p.Splits
r i : R
⊢ (X + C r + C i).Splits

Tactic:
simpa using

Goal state after:
R : Type u_1
inst✝ : CommSemiring R
p : R[X]
hp : p.Splits
r i : R
⊢ (X + (C r + C i)).Splits
Module: Mathlib.Algebra.Polynomial.Splits

Goal state before:
pp: R : Type u_1
inst✝ : CommSemiring R
f : R[X]
hf : f.Splits
a✝ : Nontrivial R
a : R
m : Multiset R
hm : f = C f.leadingCoeff * ((X + C a) * (Multiset.map (fun x ↦ X + C x) m).prod)
ha : a ∈ a ::ₘ m
h : (Irreducible (X + C a) ∧ ∀ m_1 ∈ (Multiset.map (fun x ↦ X + C x) m).toList, IsUnit m_1) ∧ IsUnit (C f.leadingCoeff)
⊢ m = 0

Tactic:
simpa using

Goal state after:
R : Type u_1
inst✝ : CommSemiring R
f : R[X]
hf : f.Splits
a✝ : Nontrivial R
a : R
m : Multiset R
hm : f = C f.leadingCoeff * ((X + C a) * (Multiset.map (fun x ↦ X + C x) m).prod)
ha : a ∈ a ::ₘ m
h : (Irreducible (X + C a) ∧ ∀ m_1 ∈ (Multiset.map (fun x ↦ X + C x) m).toList, IsUnit m_1) ∧ IsUnit (C f.leadingCoeff)
⊢ m = 0
Module: Mathlib.Algebra.Polynomial.Splits

Goal state before:
pp: R : Type u_1
inst✝ : CommSemiring R
f : R[X]
hf : f.Splits
h : Irreducible f
⊢ f.natDegree ≤ 1

Tactic:
nontriviality R
  obtain ⟨m, hm⟩ := splits_iff_exists_multiset'.mp hf
  rcases m.empty_or_exists_mem with rfl | ⟨a, ha⟩
  · rw [hm]
    simp
  · obtain ⟨m, rfl⟩ := Multiset.exists_cons_of_mem ha
    rw [Multiset.map_cons, Multiset.prod_cons] at hm
    rw [hm] at h
    simp only [irreducible_mul_iff, IsUnit.mul_iff, not_isUnit_X_add_C, false_and, and_false,
      or_false, false_or, ← Multiset.prod_toList, List.prod_isUnit_iff] at h
    have : m = 0 := by simpa [not_isUnit_X_add_C, ← Multiset.eq_zero_iff_forall_notMem] using h.1.2
    grw [hm, this, natDegree_mul_le]
    simp

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

Goal state before:
pp: R : Type u_1
inst✝¹ : CommRing R
f : R[X]
inst✝ : IsDomain R
hf : f.Splits
hf0 : f.natDegree ≠ 0
⊢ f.roots ≠ 0

Tactic:
simpa using

Goal state after:
R : Type u_1
inst✝¹ : CommRing R
f : R[X]
inst✝ : IsDomain R
hf : f.Splits
hf0 : f.natDegree ≠ 0
⊢ ¬f.roots = 0
Module: Mathlib.RingTheory.Localization.Integral

Goal state before:
pp: R : Type u_1
inst✝³ : CommRing R
M : Submonoid R
S : Type u_2
inst✝² : CommRing S
inst✝¹ : Algebra R S
inst✝ : IsLocalization M S
p : S[X]
⊢ ∃ b ∈ M, ∃ q, Polynomial.map (algebraMap R S) q = b • p ∧ q.support ⊆ p.support

Tactic:
by
  obtain ⟨⟨_, b, hb, rfl⟩, h⟩ := exists_integer_multiple (Submonoid.map C M) p
  rw [Subtype.coe_mk, C_eq_algebraMap, algebraMap_smul] at h
  obtain ⟨q', h₁, h₂⟩ := exists_support_eq_of_mem_lifts h
  exact ⟨b, hb, q', h₁, h₂ ▸ support_smul b p⟩

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

Goal state before:
pp: R : Type u_1
inst✝ : Field R
F : Subfield R
f : (↥F)[X]
hf : f.Splits
hf0 : f ≠ 0
x : R
hx : (map F.subtype f).IsRoot x
⊢ x ∈ F

Tactic:
simpa using

Goal state after:
R : Type u_1
inst✝ : Field R
F : Subfield R
f : (↥F)[X]
hf : f.Splits
hf0 : f ≠ 0
x : R
hx : (map F.subtype f).IsRoot x
⊢ x ∈ F
Module: Mathlib.Algebra.Polynomial.Splits

Goal state before:
pp: R : Type u_1
inst✝ : Field R
f : R[X]
x : R
h₁ : f.natDegree = 2
h₂ : eval x f = 0
⊢ (f /ₘ (X - C x)).natDegree = 1

Tactic:
rw [natDegree_divByMonic f (monic_X_sub_C x), h₁, natDegree_X_sub_C]

Goal state after:
Module: Mathlib.RingTheory.Flat.FaithfullyFlat.Basic

Goal state before:
pp: R : Type u
M : Type v
inst✝² : CommRing R
inst✝¹ : AddCommGroup M
inst✝ : Module R M
m : Ideal R
h : m.IsMaximal
r : m • ⊤ = ⊤
⊢ 1 ∈ m

Tactic:
simpa using

Goal state after:
R : Type u
M : Type v
inst✝² : CommRing R
inst✝¹ : AddCommGroup M
inst✝ : Module R M
m : Ideal R
h : m.IsMaximal
r : m • ⊤ = ⊤
⊢ 1 ∈ m
Module: Mathlib.RingTheory.Flat.FaithfullyFlat.Basic

Goal state before:
pp: R : Type u
M : Type v
inst✝² : CommRing R
inst✝¹ : AddCommGroup M
inst✝ : Module R M
x✝ : Flat R M ∧ ∀ ⦃m : Ideal R⦄, m.IsMaximal → m • ⊤ ≠ ⊤
flat : Flat R M
h : ∀ ⦃m : Ideal R⦄, m.IsMaximal → m • ⊤ ≠ ⊤
I : Ideal R
hI : I ≠ ⊤
r : I • ⊤ = ⊤
m : Ideal R
hm : m.IsMaximal
le : I ≤ m
⊢ ⊤ ≤ I • ⊤

Tactic:
simp [r]

Goal state after:
Module: Mathlib.RingTheory.Flat.FaithfullyFlat.Basic

Goal state before:
pp: R : Type u
M : Type v
inst✝⁵ : CommRing R
inst✝⁴ : AddCommGroup M
inst✝³ : Module R M
fl : FaithfullyFlat R M
N : Type u_1
inst✝² : AddCommGroup N
inst✝¹ : Module R N
inst✝ : Nontrivial N
n : N
hn : n ≠ 0
I : Ideal R := (R ∙ n).annihilator
I_ne_top : ¬I = ⊤
r : R
hr : r ∈ I
⊢ r ∈ ((LinearMap.lsmul R N).flip n).ker

Tactic:
simpa using

Goal state after:
R : Type u
M : Type v
inst✝⁵ : CommRing R
inst✝⁴ : AddCommGroup M
inst✝³ : Module R M
fl : FaithfullyFlat R M
N : Type u_1
inst✝² : AddCommGroup N
inst✝¹ : Module R N
inst✝ : Nontrivial N
n : N
hn : n ≠ 0
I : Ideal R := (R ∙ n).annihilator
I_ne_top : ¬I = ⊤
r : R
hr : r ∈ I
⊢ r • n = 0
Module: Mathlib.RingTheory.Ideal.GoingUp

Goal state before:
pp: case refine_3
R : Type u_1
inst✝¹ : CommRing R
S : Type u_2
inst✝ : CommRing S
f : R →+* S
I : Ideal S
r : S
r_non_zero_divisor : ∀ {x : S}, x * r = 0 → x = 0
hr : r ∈ I
p✝ p : R[X]
p_nonzero : p ≠ 0
ih : p ≠ 0 → eval₂ f r p = 0 → ∃ i, p.coeff i ≠ 0 ∧ p.coeff i ∈ comap f I
a✝ : p * X ≠ 0
hp : eval₂ f r p * r = 0
i : ℕ
hi : p.coeff i ≠ 0
mem : p.coeff i ∈ comap f I
⊢ ∃ i, (p * X).coeff i ≠ 0 ∧ (p * X).coeff i ∈ comap f I

Tactic:
refine ⟨i + 1, ?_, ?_⟩

Goal state after:
case refine_3.refine_1
R : Type u_1
inst✝¹ : CommRing R
S : Type u_2
inst✝ : CommRing S
f : R →+* S
I : Ideal S
r : S
r_non_zero_divisor : ∀ {x : S}, x * r = 0 → x = 0
hr : r ∈ I
p✝ p : R[X]
p_nonzero : p ≠ 0
ih : p ≠ 0 → eval₂ f r p = 0 → ∃ i, p.coeff i ≠ 0 ∧ p.coeff i ∈ comap f I
a✝ : p * X ≠ 0
hp : eval₂ f r p * r = 0
i : ℕ
hi : p.coeff i ≠ 0
mem : p.coeff i ∈ comap f I
⊢ (p * X).coeff (i + 1) ≠ 0

case refine_3.refine_2
R : Type u_1
inst✝¹ : CommRing R
S : Type u_2
inst✝ : CommRing S
f : R →+* S
I : Ideal S
r : S
r_non_zero_divisor : ∀ {x : S}, x * r = 0 → x = 0
hr : r ∈ I
p✝ p : R[X]
p_nonzero : p ≠ 0
ih : p ≠ 0 → eval₂ f r p = 0 → ∃ i, p.coeff i ≠ 0 ∧ p.coeff i ∈ comap f I
a✝ : p * X ≠ 0
hp : eval₂ f r p * r = 0
i : ℕ
hi : p.coeff i ≠ 0
mem : p.coeff i ∈ comap f I
⊢ (p * X).coeff (i + 1) ∈ comap f I
Module: Mathlib.RingTheory.Flat.FaithfullyFlat.Basic

Goal state before:
pp: case h
R : Type u
M : Type v
inst✝⁵ : CommRing R
inst✝⁴ : AddCommGroup M
inst✝³ : Module R M
fl : FaithfullyFlat R M
N : Type u_1
inst✝² : AddCommGroup N
inst✝¹ : Module R N
inst✝ : Nontrivial N
n : N
hn : n ≠ 0
I : Ideal R := (R ∙ n).annihilator
I_ne_top : ¬I = ⊤
inc : R ⧸ I →ₗ[R] N := Submodule.liftQ I ((LinearMap.lsmul R N).flip n) ⋯
r : R
hr : Quotient.mk'' r ∈ inc.ker
⊢ Quotient.mk'' r ∈ ⊥

Tactic:
simpa using

Goal state after:
case h
R : Type u
M : Type v
inst✝⁵ : CommRing R
inst✝⁴ : AddCommGroup M
inst✝³ : Module R M
fl : FaithfullyFlat R M
N : Type u_1
inst✝² : AddCommGroup N
inst✝¹ : Module R N
inst✝ : Nontrivial N
n : N
hn : n ≠ 0
I : Ideal R := (R ∙ n).annihilator
I_ne_top : ¬I = ⊤
inc : R ⧸ I →ₗ[R] N := Submodule.liftQ I ((LinearMap.lsmul R N).flip n) ⋯
r : R
hr : Quotient.mk'' r ∈ inc.ker
⊢ r • n = 0
Module: Mathlib.RingTheory.Ideal.GoingUp

Goal state before:
pp: case refine_3.refine_2
R : Type u_1
inst✝¹ : CommRing R
S : Type u_2
inst✝ : CommRing S
f : R →+* S
I : Ideal S
r : S
r_non_zero_divisor : ∀ {x : S}, x * r = 0 → x = 0
hr : r ∈ I
p✝ p : R[X]
p_nonzero : p ≠ 0
ih : p ≠ 0 → eval₂ f r p = 0 → ∃ i, p.coeff i ≠ 0 ∧ p.coeff i ∈ comap f I
a✝ : p * X ≠ 0
hp : eval₂ f r p * r = 0
i : ℕ
hi : p.coeff i ≠ 0
mem : p.coeff i ∈ comap f I
⊢ (p * X).coeff (i + 1) ∈ comap f I

Tactic:
simpa using

Goal state after:
case refine_3.refine_2
R : Type u_1
inst✝¹ : CommRing R
S : Type u_2
inst✝ : CommRing S
f : R →+* S
I : Ideal S
r : S
r_non_zero_divisor : ∀ {x : S}, x * r = 0 → x = 0
hr : r ∈ I
p✝ p : R[X]
p_nonzero : p ≠ 0
ih : p ≠ 0 → eval₂ f r p = 0 → ∃ i, p.coeff i ≠ 0 ∧ p.coeff i ∈ comap f I
a✝ : p * X ≠ 0
hp : eval₂ f r p * r = 0
i : ℕ
hi : p.coeff i ≠ 0
mem : p.coeff i ∈ comap f I
⊢ f (p.coeff i) ∈ I
Module: Mathlib.RingTheory.Localization.Integral

Goal state before:
pp: R : Type u_5
S : Type u_6
Sₘ : Type u_7
inst✝⁷ : CommRing R
inst✝⁶ : CommRing S
inst✝⁵ : CommRing Sₘ
inst✝⁴ : Algebra R S
inst✝³ : Algebra S Sₘ
inst✝² : Algebra R Sₘ
inst✝¹ : IsScalarTower R S Sₘ
r : S
hr : IsIntegral R r
inst✝ : Away r Sₘ
x : S
a✝ : Nontrivial S
p : R[X]
hpm : p.Monic
m : ℕ
hm : r ^ m * eval₂ (algebraMap R S) x p = 0
⊢ (aeval x) (C ⟨r, hr⟩ ^ m * Polynomial.map (algebraMap R ↥(integralClosure R S)) p) = 0

Tactic:
simpa using

Goal state after:
R : Type u_5
S : Type u_6
Sₘ : Type u_7
inst✝⁷ : CommRing R
inst✝⁶ : CommRing S
inst✝⁵ : CommRing Sₘ
inst✝⁴ : Algebra R S
inst✝³ : Algebra S Sₘ
inst✝² : Algebra R Sₘ
inst✝¹ : IsScalarTower R S Sₘ
r : S
hr : IsIntegral R r
inst✝ : Away r Sₘ
x : S
a✝ : Nontrivial S
p : R[X]
hpm : p.Monic
m : ℕ
hm : r ^ m * eval₂ (algebraMap R S) x p = 0
⊢ r ^ m * (aeval x) p = 0
Module: Mathlib.RingTheory.Ideal.GoingUp

Goal state before:
pp: case refine_1
R : Type u_1
inst✝² : CommRing R
S : Type u_2
inst✝¹ : CommRing S
f : R →+* S
I J : Ideal S
inst✝ : I.IsPrime
hIJ : I ≤ J
r : S
p : R[X]
p_ne_zero : Polynomial.map (Quotient.mk (comap f I)) p ≠ 0
hpI : eval₂ f r p ∈ I
hrJ : r ∈ ↑J
hrI : r ∉ ↑I
rbar_ne_zero : (Quotient.mk I) r ≠ 0
rbar_mem_J : (Quotient.mk I) r ∈ map (Quotient.mk I) J
quotient_f : ∀ x ∈ comap f I, ((Quotient.mk I).comp f) x = 0
rbar_root :
  eval₂ (Quotient.lift (comap f I) ((Quotient.mk I).comp f) quotient_f) ((Quotient.mk I) r)
      (Polynomial.map (Quotient.mk (comap f I)) p) =
    0
i : ℕ
ne_zero : (Quotient.mk (comap f I)) (p.coeff i) ≠ 0
mem :
  (Quotient.mk (comap f I)) (p.coeff i) ∈
    comap (Quotient.lift (comap f I) ((Quotient.mk I).comp f) quotient_f) (map (Quotient.mk I) J)
⊢ (Quotient.mk I) (f (p.coeff i)) ∈ map (Quotient.mk I) J

Tactic:
simpa using

Goal state after:
case refine_1
R : Type u_1
inst✝² : CommRing R
S : Type u_2
inst✝¹ : CommRing S
f : R →+* S
I J : Ideal S
inst✝ : I.IsPrime
hIJ : I ≤ J
r : S
p : R[X]
p_ne_zero : Polynomial.map (Quotient.mk (comap f I)) p ≠ 0
hpI : eval₂ f r p ∈ I
hrJ : r ∈ ↑J
hrI : r ∉ ↑I
rbar_ne_zero : (Quotient.mk I) r ≠ 0
rbar_mem_J : (Quotient.mk I) r ∈ map (Quotient.mk I) J
quotient_f : ∀ x ∈ comap f I, ((Quotient.mk I).comp f) x = 0
rbar_root :
  eval₂ (Quotient.lift (comap f I) ((Quotient.mk I).comp f) quotient_f) ((Quotient.mk I) r)
      (Polynomial.map (Quotient.mk (comap f I)) p) =
    0
i : ℕ
ne_zero : (Quotient.mk (comap f I)) (p.coeff i) ≠ 0
mem :
  (Quotient.mk (comap f I)) (p.coeff i) ∈
    comap (Quotient.lift (comap f I) ((Quotient.mk I).comp f) quotient_f) (map (Quotient.mk I) J)
⊢ f (p.coeff i) ∈ J ⊔ I
Module: Mathlib.RingTheory.Algebraic.Integral

Goal state before:
pp: R : Type u_1
A : Type u_3
inst✝² : CommRing R
inst✝¹ : Ring A
inst✝ : Algebra R A
z : A
hz : IsAlgebraic R z
inj : ∃ a, (algebraMap R A) a = 0 ∧ a ≠ 0
r : R
eq : (algebraMap R A) r = 0
ne : r ≠ 0
⊢ IsIntegral R (r • z)

Tactic:
simpa using

Goal state after:
R : Type u_1
A : Type u_3
inst✝² : CommRing R
inst✝¹ : Ring A
inst✝ : Algebra R A
z : A
hz : IsAlgebraic R z
inj : ∃ a, (algebraMap R A) a = 0 ∧ a ≠ 0
r : R
eq : (algebraMap R A) r = 0
ne : r ≠ 0
⊢ IsIntegral R 0
Module: Mathlib.RingTheory.Flat.FaithfullyFlat.Basic

Goal state before:
pp: R : Type u
M✝ : Type v
inst✝⁶ : CommRing R
inst✝⁵ : AddCommGroup M✝
inst✝⁴ : Module R M✝
ι : Type u_1
inst✝³ : Nonempty ι
M : ι → Type u_2
inst✝² : (i : ι) → AddCommGroup (M i)
inst✝¹ : (i : ι) → Module R (M i)
inst✝ : ∀ (i : ι), FaithfullyFlat R (M i)
N : Type (max u u_1 u_2)
x✝¹ : AddCommGroup N
x✝ : Module R N
hN : Nontrivial N
⊢ Nontrivial ((⨁ (i : ι), M i) ⊗[R] N)

Tactic:
obtain ⟨i⟩ := ‹Nonempty ι›

Goal state after:
R : Type u
M✝ : Type v
inst✝⁶ : CommRing R
inst✝⁵ : AddCommGroup M✝
inst✝⁴ : Module R M✝
ι : Type u_1
inst✝³ : Nonempty ι
M : ι → Type u_2
inst✝² : (i : ι) → AddCommGroup (M i)
inst✝¹ : (i : ι) → Module R (M i)
inst✝ : ∀ (i : ι), FaithfullyFlat R (M i)
N : Type (max u u_1 u_2)
x✝¹ : AddCommGroup N
x✝ : Module R N
hN : Nontrivial N
i : ι
⊢ Nontrivial ((⨁ (i : ι), M i) ⊗[R] N)
Module: Mathlib.RingTheory.Flat.FaithfullyFlat.Basic

Goal state before:
pp: R : Type u
M : Type v
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : Module R M
N1 : Type u_1
inst✝⁵ : AddCommGroup N1
inst✝⁴ : Module R N1
N2 : Type u_2
inst✝³ : AddCommGroup N2
inst✝² : Module R N2
N3 : Type u_3
inst✝¹ : AddCommGroup N3
inst✝ : Module R N3
l12 : N1 →ₗ[R] N2
l23 : N2 →ₗ[R] N3
fl : FaithfullyFlat R M
ex : Function.Exact ⇑(LinearMap.rTensor M l12) ⇑(LinearMap.rTensor M l23)
n1 : N1
hn1 : l23 (l12 n1) ≠ 0
E : Submodule R N3 := R ∙ l23 (l12 n1)
hE : Nontrivial ↥E
eq1 : ∀ (m : M), l23 (l12 n1) ⊗ₜ[R] m = 0
x : ↥E ⊗[R] M
mem : x ∈ Submodule.span R {t | ∃ m n, m ⊗ₜ[R] n = t}
⊢ x = 0

Tactic:
Submodule.mem_span_set

Goal state after:
R : Type u
M : Type v
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : Module R M
N1 : Type u_1
inst✝⁵ : AddCommGroup N1
inst✝⁴ : Module R N1
N2 : Type u_2
inst✝³ : AddCommGroup N2
inst✝² : Module R N2
N3 : Type u_3
inst✝¹ : AddCommGroup N3
inst✝ : Module R N3
l12 : N1 →ₗ[R] N2
l23 : N2 →ₗ[R] N3
fl : FaithfullyFlat R M
ex : Function.Exact ⇑(LinearMap.rTensor M l12) ⇑(LinearMap.rTensor M l23)
n1 : N1
hn1 : l23 (l12 n1) ≠ 0
E : Submodule R N3 := R ∙ l23 (l12 n1)
hE : Nontrivial ↥E
eq1 : ∀ (m : M), l23 (l12 n1) ⊗ₜ[R] m = 0
x : ↥E ⊗[R] M
mem : ∃ c, ↑c.support ⊆ {t | ∃ m n, m ⊗ₜ[R] n = t} ∧ (c.sum fun mi r ↦ r • mi) = x
⊢ x = 0