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

Goal state before:
pp: R✝ : Type u_1
S : Type u_2
P : Type u_3
Q : Type u_4
inst✝²⁹ : CommSemiring R✝
inst✝²⁸ : CommSemiring S
inst✝²⁷ : CommSemiring P
inst✝²⁶ : CommSemiring Q
M✝ : Submonoid R✝
T : Submonoid P
inst✝²⁵ : Algebra R✝ S
inst✝²⁴ : Algebra P Q
inst✝²³ : IsLocalization M✝ S
inst✝²² : IsLocalization T Q
g : R✝ →+* P
R : Type u_5
inst✝²¹ : CommSemiring R
M : Submonoid R
A : Type u_6
inst✝²⁰ : CommSemiring A
inst✝¹⁹ : Algebra R A
B : Type u_7
inst✝¹⁸ : CommSemiring B
inst✝¹⁷ : Algebra R B
Rₚ : Type u_8
inst✝¹⁶ : CommSemiring Rₚ
inst✝¹⁵ : Algebra R Rₚ
inst✝¹⁴ : IsLocalization M Rₚ
Aₚ : Type u_9
inst✝¹³ : CommSemiring Aₚ
inst✝¹² : Algebra R Aₚ
inst✝¹¹ : Algebra A Aₚ
inst✝¹⁰ : IsScalarTower R A Aₚ
inst✝⁹ : IsLocalization (algebraMapSubmonoid A M) Aₚ
Bₚ : Type u_10
inst✝⁸ : CommSemiring Bₚ
inst✝⁷ : Algebra R Bₚ
inst✝⁶ : Algebra B Bₚ
inst✝⁵ : IsScalarTower R B Bₚ
inst✝⁴ : IsLocalization (algebraMapSubmonoid B M) Bₚ
inst✝³ : Algebra Rₚ Aₚ
inst✝² : Algebra Rₚ Bₚ
inst✝¹ : IsScalarTower R Rₚ Aₚ
inst✝ : IsScalarTower R Rₚ Bₚ
f : A →ₐ[R] B
a : R
m : ↥M
⊢ (↑↑(map Bₚ f.toRingHom ⋯)).toFun ((algebraMap Rₚ Aₚ) (mk' Rₚ a m)) = (algebraMap Rₚ Bₚ) (mk' Rₚ a m)

Tactic:
simp [algebraMap_mk' (S := A), algebraMap_mk' (S := B), map_mk']

Goal state after:
Module: Mathlib.RingTheory.Localization.LocalizationLocalization

Goal state before:
pp: case mp
R : Type u_1
inst✝² : CommSemiring R
M : Submonoid R
S : Type u_2
inst✝¹ : CommSemiring S
inst✝ : Algebra R S
N : Submonoid S
x : R
⊢ (∃ y ∈ N, ∃ z ∈ Submonoid.map (algebraMap R S) M, y * z = (algebraMap R S) x) →
    ∃ y z, (algebraMap R S) x = ↑y * (algebraMap R S) ↑z

pp: case mpr
R : Type u_1
inst✝² : CommSemiring R
M : Submonoid R
S : Type u_2
inst✝¹ : CommSemiring S
inst✝ : Algebra R S
N : Submonoid S
x : R
⊢ (∃ y z, (algebraMap R S) x = ↑y * (algebraMap R S) ↑z) →
    ∃ y ∈ N, ∃ z ∈ Submonoid.map (algebraMap R S) M, y * z = (algebraMap R S) x

Tactic:
· rintro ⟨y, hy, _, ⟨z, hz, rfl⟩, e⟩
    exact ⟨⟨y, hy⟩, ⟨z, hz⟩, e.symm⟩

Goal state after:
case mpr
R : Type u_1
inst✝² : CommSemiring R
M : Submonoid R
S : Type u_2
inst✝¹ : CommSemiring S
inst✝ : Algebra R S
N : Submonoid S
x : R
⊢ (∃ y z, (algebraMap R S) x = ↑y * (algebraMap R S) ↑z) →
    ∃ y ∈ N, ∃ z ∈ Submonoid.map (algebraMap R S) M, y * z = (algebraMap R S) x
Module: Mathlib.LinearAlgebra.TensorProduct.Quotient

Goal state before:
pp: R : Type u_1
M : Type u_2
N : Type u_3
inst✝⁴ : CommRing R
inst✝³ : AddCommGroup M
inst✝² : Module R M
inst✝¹ : AddCommGroup N
inst✝ : Module R N
I : Ideal R
⊢ Submodule.map (↑(TensorProduct.lid R M)) (map (Submodule.subtype I) LinearMap.id).range = I • ⊤

Tactic:
rw [← LinearMap.range_comp, ← (Submodule.topEquiv.lTensor I).range_comp, Submodule.smul_eq_map₂,
      map₂_eq_range_lift_comp_mapIncl]
    exact congr_arg _ (TensorProduct.ext' fun _ _ ↦ by simp)

Goal state after:
Module: Mathlib.LinearAlgebra.TensorProduct.Quotient

Goal state before:
pp: case refine_2
R : Type u_1
A : Type u_2
inst✝¹⁰ : CommRing R
inst✝⁹ : CommRing A
inst✝⁸ : Algebra R A
M : Type u_4
inst✝⁷ : AddCommGroup M
inst✝⁶ : Module R M
inst✝⁵ : Module A M
inst✝⁴ : IsScalarTower R A M
N : Type u_5
inst✝³ : AddCommGroup N
inst✝² : Module R N
inst✝¹ : Module A N
inst✝ : IsScalarTower R A N
S : Submodule A (M ⊗[R] N) := Submodule.span A {x | ∃ a m n, (a • m) ⊗ₜ[R] n - m ⊗ₜ[R] (a • n) = x}
⊢ (mapOfCompatibleSMul A R A M N).ker ≤ Submodule.span A {x | ∃ a m n, (a • m) ⊗ₜ[R] n - m ⊗ₜ[R] (a • n) = x}

Tactic:
let F : M ⊗[A] N →ₗ[A] (M ⊗[R] N) ⧸ S := TensorProduct.lift ({
      toFun m := {
        toFun n := S.mkQ (m ⊗ₜ[R] n)
        map_add' _ _ := by simp [tmul_add]
        map_smul' a n := by
          rw [Submodule.mkQ_apply, Submodule.mkQ_apply, ← Submodule.Quotient.mk_smul, eq_comm,
            Submodule.Quotient.eq, RingHom.id_apply]
          exact Submodule.subset_span ⟨a, m, n, rfl⟩ }
      map_add' _ _ := by ext _; simp [add_tmul]
      map_smul' _ _ := by simp; rfl })

Goal state after:
case refine_2
R : Type u_1
A : Type u_2
inst✝¹⁰ : CommRing R
inst✝⁹ : CommRing A
inst✝⁸ : Algebra R A
M : Type u_4
inst✝⁷ : AddCommGroup M
inst✝⁶ : Module R M
inst✝⁵ : Module A M
inst✝⁴ : IsScalarTower R A M
N : Type u_5
inst✝³ : AddCommGroup N
inst✝² : Module R N
inst✝¹ : Module A N
inst✝ : IsScalarTower R A N
S : Submodule A (M ⊗[R] N) := Submodule.span A {x | ∃ a m n, (a • m) ⊗ₜ[R] n - m ⊗ₜ[R] (a • n) = x}
F : M ⊗[A] N →ₗ[A] M ⊗[R] N ⧸ S :=
  TensorProduct.lift
    { toFun := fun m ↦ { toFun := fun n ↦ S.mkQ (m ⊗ₜ[R] n), map_add' := ⋯, map_smul' := ⋯ }, map_add' := ⋯,
      map_smul' := ⋯ }
⊢ (mapOfCompatibleSMul A R A M N).ker ≤ Submodule.span A {x | ∃ a m n, (a • m) ⊗ₜ[R] n - m ⊗ₜ[R] (a • n) = x}
Module: Mathlib.RingTheory.Localization.AtPrime.Basic

Goal state before:
pp: R : Type u_1
inst✝⁵ : CommSemiring R
q : Ideal R
inst✝⁴ : q.IsPrime
S : Type u_4
inst✝³ : CommSemiring S
inst✝² : Algebra R S
inst✝¹ : IsLocalization.AtPrime S q
p : Ideal R
inst✝ : p.IsPrime
hpq : p ≤ q
⊢ Disjoint ↑q.primeCompl ↑p

Tactic:
simp [Ideal.primeCompl, ← le_compl_iff_disjoint_left, hpq]

Goal state after:
Module: Mathlib.RingTheory.Localization.Submodule

Goal state before:
pp: R : Type u_1
inst✝⁷ : CommSemiring R
M : Submonoid R
S : Type u_2
inst✝⁶ : CommSemiring S
inst✝⁵ : Algebra R S
inst✝⁴ : IsLocalization M S
N : Type u_3
inst✝³ : AddCommMonoid N
inst✝² : Module R N
inst✝¹ : Module S N
inst✝ : IsScalarTower R S N
x : N
a : Set N
⊢ x ∈ Submodule.span S a ↔ ∃ y ∈ Submodule.span R a, ∃ z, x = mk' S 1 z • y

Tactic:
by
  constructor
  · intro h
    refine Submodule.span_induction ?_ ?_ ?_ ?_ h
    · rintro x hx
      exact ⟨x, Submodule.subset_span hx, 1, by rw [mk'_one, map_one, one_smul]⟩
    · exact ⟨0, Submodule.zero_mem _, 1, by rw [mk'_one, map_one, one_smul]⟩
    · rintro _ _ _ _ ⟨y, hy, z, rfl⟩ ⟨y', hy', z', rfl⟩
      refine
        ⟨(z' : R) • y + (z : R) • y',
          Submodule.add_mem _ (Submodule.smul_mem _ _ hy) (Submodule.smul_mem _ _ hy'), z * z', ?_⟩
      rw [smul_add, ← IsScalarTower.algebraMap_smul S (z : R), ←
        IsScalarTower.algebraMap_smul S (z' : R), smul_smul, smul_smul]
      congr 1
      · rw [← mul_one (1 : R), mk'_mul, mul_assoc, mk'_spec, map_one, mul_one, mul_one]
      · rw [← mul_one (1 : R), mk'_mul, mul_right_comm, mk'_spec, map_one, mul_one, one_mul]
    · rintro a _ _ ⟨y, hy, z, rfl⟩
      obtain ⟨y', z', rfl⟩ := exists_mk'_eq M a
      refine ⟨y' • y, Submodule.smul_mem _ _ hy, z' * z, ?_⟩
      rw [← IsScalarTower.algebraMap_smul S y', smul_smul, ← mk'_mul, smul_smul,
        mul_comm (mk' S _ _), mul_mk'_eq_mk'_of_mul]
  · rintro ⟨y, hy, z, rfl⟩
    exact Submodule.smul_mem _ _ (Submodule.span_subset_span R S _ hy)

Goal state after:
Module: Mathlib.LinearAlgebra.Matrix.Polynomial

Goal state before:
pp: n : Type u_1
α : Type u_2
inst✝² : DecidableEq n
inst✝¹ : Fintype n
inst✝ : CommRing α
A B : Matrix n n α
⊢ (X • A.map ⇑C + B.map ⇑C).det.coeff (Fintype.card n) = A.det

Tactic:
by
  rw [det_apply, det_apply, finsetSum_coeff]
  refine Finset.sum_congr rfl ?_
  simp only [Finset.mem_univ, forall_true_left]
  intro g
  convert! coeff_smul (R := α) (sign g) _ _
  rw [← mul_one (Fintype.card n)]
  convert! (coeff_prod_of_natDegree_le (R := α) _ _ _ _).symm
  · simp [coeff_C]
  · rintro p -
    dsimp only [Matrix.add_apply, Matrix.smul_apply, map_apply, smul_eq_mul]
    compute_degree

Goal state after:
Module: Mathlib.LinearAlgebra.Dimension.Localization

Goal state before:
pp: case inl
R : Type uR
S : Type uS
N : Type uN
inst✝⁷ : CommRing R
inst✝⁶ : CommRing S
inst✝⁵ : AddCommGroup N
inst✝⁴ : Module R N
inst✝³ : Algebra R S
inst✝² : Module S N
inst✝¹ : IsScalarTower R S N
p : Submonoid R
inst✝ : IsLocalization p S
hp : p ≤ R⁰
h✝ : Subsingleton R
⊢ Module.rank S N = Module.rank R N

Tactic:
have := (algebraMap R S).codomain_trivial; simp only [rank_subsingleton]

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

Goal state before:
pp: R : Type u_1
inst✝ : Semiring R
n : ℤ
r : R
⊢ (comapDomainAddMonoidHom Nat.cast trunc._proof_1) (AddMonoidAlgebra.single n r) =
    (if 0 ≤ n then (monomial n.toNat) r else 0).toFinsupp

Tactic:
split_ifs with hn

Goal state after:
case pos
R : Type u_1
inst✝ : Semiring R
n : ℤ
r : R
hn : 0 ≤ n
⊢ (comapDomainAddMonoidHom Nat.cast trunc._proof_1) (AddMonoidAlgebra.single n r) = ((monomial n.toNat) r).toFinsupp

case neg
R : Type u_1
inst✝ : Semiring R
n : ℤ
r : R
hn : ¬0 ≤ n
⊢ (comapDomainAddMonoidHom Nat.cast trunc._proof_1) (AddMonoidAlgebra.single n r) = toFinsupp 0
Module: Mathlib.Algebra.Polynomial.Laurent

Goal state before:
pp: R : Type u_1
inst✝ : CommSemiring R
p : R[X]
n : ℕ
⊢ IsLocalization.mk' R[T;T⁻¹] p ⟨X ^ n, ⋯⟩ = toLaurent p * T (-↑n)

Tactic:
rw [← IsUnit.mul_left_inj (isUnit_T n), mul_T_assoc, neg_add_cancel, T_zero, mul_one]

Goal state after:
R : Type u_1
inst✝ : CommSemiring R
p : R[X]
n : ℕ
⊢ IsLocalization.mk' R[T;T⁻¹] p ⟨X ^ n, ⋯⟩ * T ↑n = toLaurent p
Module: Mathlib.LinearAlgebra.Matrix.Adjugate

Goal state before:
pp: n : Type v
inst✝³ : DecidableEq n
inst✝² : Fintype n
R : Type u_1
S : Type u_2
inst✝¹ : CommRing R
inst✝ : CommRing S
f : R →+* S
M : Matrix n n R
i k : n
⊢ f.mapMatrix M.adjugate i k = (f.mapMatrix M).adjugate i k

Tactic:
have : Pi.single i (1 : S) = f ∘ Pi.single i 1 := by
    rw [← f.map_one]
    exact Pi.single_op (fun _ => f) (fun _ => f.map_zero) i (1 : R)

Goal state after:
n : Type v
inst✝³ : DecidableEq n
inst✝² : Fintype n
R : Type u_1
S : Type u_2
inst✝¹ : CommRing R
inst✝ : CommRing S
f : R →+* S
M : Matrix n n R
i k : n
this : Pi.single i 1 = ⇑f ∘ Pi.single i 1
⊢ f.mapMatrix M.adjugate i k = (f.mapMatrix M).adjugate i k
Module: Mathlib.LinearAlgebra.Matrix.Adjugate

Goal state before:
pp: α : Type w
inst✝ : CommRing α
n : ℕ
A : Matrix (Fin n.succ) (Fin n.succ) α
i j h : Fin n.succ
hjk : h ≠ i
⊢ (-1) ^ (↑j + ↑h) * Pi.single i 1 h * (A.submatrix j.succAbove h.succAbove).det = 0

Tactic:
rw [Pi.single_eq_of_ne hjk, mul_zero, zero_mul]

Goal state after:
Module: Mathlib.LinearAlgebra.Matrix.Transvection

Goal state before:
pp: case of_succ
𝕜 : Type u_3
inst✝ : Field 𝕜
r : ℕ
M : Matrix (Fin r ⊕ Unit) (Fin r ⊕ Unit) 𝕜
hM : M (inr ()) (inr ()) ≠ 0
i : Fin r
k n : ℕ
hn : n < r
IH : ((List.drop (n + 1) (listTransvecCol M)).prod * M) (inl i) (inr ()) = if n + 1 ≤ ↑i then 0 else M (inl i) (inr ())
hn' : n < (listTransvecCol M).length
n' : Fin r := ⟨n, hn⟩
A : (listTransvecCol M)[n] = transvection (inl n') (inr ()) (-M (inl n') (inr ()) / M (inr ()) (inr ()))
⊢ (transvection (inl n') (inr ()) (-M (inl n') (inr ()) / M (inr ()) (inr ())) *
        ((List.drop (n + 1) (listTransvecCol M)).prod * M))
      (inl i) (inr ()) =
    if n ≤ ↑i then 0 else M (inl i) (inr ())

Tactic:
by_cases h : n' = i

Goal state after:
case pos
𝕜 : Type u_3
inst✝ : Field 𝕜
r : ℕ
M : Matrix (Fin r ⊕ Unit) (Fin r ⊕ Unit) 𝕜
hM : M (inr ()) (inr ()) ≠ 0
i : Fin r
k n : ℕ
hn : n < r
IH : ((List.drop (n + 1) (listTransvecCol M)).prod * M) (inl i) (inr ()) = if n + 1 ≤ ↑i then 0 else M (inl i) (inr ())
hn' : n < (listTransvecCol M).length
n' : Fin r := ⟨n, hn⟩
A : (listTransvecCol M)[n] = transvection (inl n') (inr ()) (-M (inl n') (inr ()) / M (inr ()) (inr ()))
h : n' = i
⊢ (transvection (inl n') (inr ()) (-M (inl n') (inr ()) / M (inr ()) (inr ())) *
        ((List.drop (n + 1) (listTransvecCol M)).prod * M))
      (inl i) (inr ()) =
    if n ≤ ↑i then 0 else M (inl i) (inr ())

case neg
𝕜 : Type u_3
inst✝ : Field 𝕜
r : ℕ
M : Matrix (Fin r ⊕ Unit) (Fin r ⊕ Unit) 𝕜
hM : M (inr ()) (inr ()) ≠ 0
i : Fin r
k n : ℕ
hn : n < r
IH : ((List.drop (n + 1) (listTransvecCol M)).prod * M) (inl i) (inr ()) = if n + 1 ≤ ↑i then 0 else M (inl i) (inr ())
hn' : n < (listTransvecCol M).length
n' : Fin r := ⟨n, hn⟩
A : (listTransvecCol M)[n] = transvection (inl n') (inr ()) (-M (inl n') (inr ()) / M (inr ()) (inr ()))
h : ¬n' = i
⊢ (transvection (inl n') (inr ()) (-M (inl n') (inr ()) / M (inr ()) (inr ())) *
        ((List.drop (n + 1) (listTransvecCol M)).prod * M))
      (inl i) (inr ()) =
    if n ≤ ↑i then 0 else M (inl i) (inr ())
Module: Mathlib.LinearAlgebra.Matrix.NonsingularInverse

Goal state before:
pp: case pos
n : Type u'
α : Type v
inst✝² : Fintype n
inst✝¹ : DecidableEq n
inst✝ : CommRing α
A : Matrix n n α
h_det : IsUnit A.det
⊢ A⁻¹ = A⁻¹ʳ

Tactic:
cases (A.isUnit_iff_isUnit_det.mpr h_det).nonempty_invertible
    rw [← invOf_eq_nonsing_inv, Ring.inverse_invertible]

Goal state after:
Module: Mathlib.LinearAlgebra.Matrix.Transvection

Goal state before:
pp: case succ
𝕜 : Type u_3
inst✝ : Field 𝕜
r : ℕ
M : Matrix (Fin r ⊕ Unit) (Fin r ⊕ Unit) 𝕜
hM : M (inr ()) (inr ()) ≠ 0
i : Fin r
n : ℕ
IH : n ≤ r → (M * (List.take n (listTransvecRow M)).prod) (inr ()) (inl i) = if n ≤ ↑i then M (inr ()) (inl i) else 0
hk : n + 1 ≤ r
hnr : n < r
n' : Fin r := ⟨n, hnr⟩
A : (listTransvecRow M)[n]? = some (transvection (inr ()) (inl n') (-M (inr ()) (inl n') / M (inr ()) (inr ())))
⊢ (M * (List.take n (listTransvecRow M)).prod *
        transvection (inr ()) (inl n') (-M (inr ()) (inl n') / M (inr ()) (inr ())))
      (inr ()) (inl i) =
    if n + 1 ≤ ↑i then M (inr ()) (inl i) else 0

Tactic:
by_cases h : n' = i

Goal state after:
case pos
𝕜 : Type u_3
inst✝ : Field 𝕜
r : ℕ
M : Matrix (Fin r ⊕ Unit) (Fin r ⊕ Unit) 𝕜
hM : M (inr ()) (inr ()) ≠ 0
i : Fin r
n : ℕ
IH : n ≤ r → (M * (List.take n (listTransvecRow M)).prod) (inr ()) (inl i) = if n ≤ ↑i then M (inr ()) (inl i) else 0
hk : n + 1 ≤ r
hnr : n < r
n' : Fin r := ⟨n, hnr⟩
A : (listTransvecRow M)[n]? = some (transvection (inr ()) (inl n') (-M (inr ()) (inl n') / M (inr ()) (inr ())))
h : n' = i
⊢ (M * (List.take n (listTransvecRow M)).prod *
        transvection (inr ()) (inl n') (-M (inr ()) (inl n') / M (inr ()) (inr ())))
      (inr ()) (inl i) =
    if n + 1 ≤ ↑i then M (inr ()) (inl i) else 0

case neg
𝕜 : Type u_3
inst✝ : Field 𝕜
r : ℕ
M : Matrix (Fin r ⊕ Unit) (Fin r ⊕ Unit) 𝕜
hM : M (inr ()) (inr ()) ≠ 0
i : Fin r
n : ℕ
IH : n ≤ r → (M * (List.take n (listTransvecRow M)).prod) (inr ()) (inl i) = if n ≤ ↑i then M (inr ()) (inl i) else 0
hk : n + 1 ≤ r
hnr : n < r
n' : Fin r := ⟨n, hnr⟩
A : (listTransvecRow M)[n]? = some (transvection (inr ()) (inl n') (-M (inr ()) (inl n') / M (inr ()) (inr ())))
h : ¬n' = i
⊢ (M * (List.take n (listTransvecRow M)).prod *
        transvection (inr ()) (inl n') (-M (inr ()) (inl n') / M (inr ()) (inr ())))
      (inr ()) (inl i) =
    if n + 1 ≤ ↑i then M (inr ()) (inl i) else 0
Module: Mathlib.LinearAlgebra.Matrix.Block

Goal state before:
pp: case e'_6
α : Type u_1
m : Type u_3
n : Type u_4
R : Type v
M : Matrix m m R
inst✝¹ : LT α
inst✝ : Zero R
b : n → α
e : m ≃ n
h : ((reindex e e) M).BlockTriangular b
⊢ M = ((reindex e e) M).submatrix ⇑e ⇑e

Tactic:
simp only [reindex_apply, submatrix_submatrix, submatrix_id_id, Equiv.symm_comp_self]

Goal state after:
Module: Mathlib.LinearAlgebra.Matrix.Block

Goal state before:
pp: case H.inr
α : Type u_1
R : Type v
inst✝⁴ : CommRing R
inst✝³ : DecidableEq α
inst✝² : LinearOrder α
m : Type u_3
M : Matrix m m R
b : m → α
inst✝¹ : DecidableEq m
inst✝ : Fintype m
hM : M.BlockTriangular b
ih :
  ∀ s ∈ image b univ,
    ∀ {m_1 : Type u_3} {M : Matrix m_1 m_1 R} {b_1 : m_1 → α} [inst : DecidableEq m_1] [inst_1 : Fintype m_1],
      M.BlockTriangular b_1 →
        image b_1 univ = (image b univ).erase s → M.det = ∏ a ∈ (image b univ).erase s, (M.toSquareBlock b_1 a).det
h✝ : Nonempty m
k : α := (image b univ).max' ⋯
⊢ M.det = ∏ a ∈ image b univ, (M.toSquareBlock b a).det

Tactic:
twoBlockTriangular_det' M fun i => b i = k

Goal state after:
case H.inr
α : Type u_1
R : Type v
inst✝⁴ : CommRing R
inst✝³ : DecidableEq α
inst✝² : LinearOrder α
m : Type u_3
M : Matrix m m R
b : m → α
inst✝¹ : DecidableEq m
inst✝ : Fintype m
hM : M.BlockTriangular b
ih :
  ∀ s ∈ image b univ,
    ∀ {m_1 : Type u_3} {M : Matrix m_1 m_1 R} {b_1 : m_1 → α} [inst : DecidableEq m_1] [inst_1 : Fintype m_1],
      M.BlockTriangular b_1 →
        image b_1 univ = (image b univ).erase s → M.det = ∏ a ∈ (image b univ).erase s, (M.toSquareBlock b_1 a).det
h✝ : Nonempty m
k : α := (image b univ).max' ⋯
⊢ (M.toSquareBlockProp fun i ↦ b i = k).det * (M.toSquareBlockProp fun i ↦ ¬b i = k).det =
    ∏ a ∈ image b univ, (M.toSquareBlock b a).det

case H.inr
α : Type u_1
R : Type v
inst✝⁴ : CommRing R
inst✝³ : DecidableEq α
inst✝² : LinearOrder α
m : Type u_3
M : Matrix m m R
b : m → α
inst✝¹ : DecidableEq m
inst✝ : Fintype m
hM : M.BlockTriangular b
ih :
  ∀ s ∈ image b univ,
    ∀ {m_1 : Type u_3} {M : Matrix m_1 m_1 R} {b_1 : m_1 → α} [inst : DecidableEq m_1] [inst_1 : Fintype m_1],
      M.BlockTriangular b_1 →
        image b_1 univ = (image b univ).erase s → M.det = ∏ a ∈ (image b univ).erase s, (M.toSquareBlock b_1 a).det
h✝ : Nonempty m
k : α := (image b univ).max' ⋯
⊢ ∀ (i : m), b i = k → ∀ (j : m), ¬b j = k → M i j = 0
Module: Mathlib.LinearAlgebra.Matrix.Transvection

Goal state before:
pp: case hmul
n : Type u_1
𝕜 : Type u_3
inst✝² : Field 𝕜
inst✝¹ : DecidableEq n
inst✝ : Fintype n
P : Matrix n n 𝕜 → Prop
M : Matrix n n 𝕜
hMdet : M.det ≠ 0
hdiag : ∀ (D : n → 𝕜), (diagonal D).det ≠ 0 → P (diagonal D)
htransvec : ∀ (t : TransvectionStruct n 𝕜), P t.toMatrix
hmul : ∀ (A B : Matrix n n 𝕜), A.det ≠ 0 → B.det ≠ 0 → P A → P B → P (A * B)
Q : Matrix n n 𝕜 → Prop := fun N ↦ N.det ≠ 0 ∧ P N
A B : Matrix n n 𝕜
QA : Q A
QB : Q B
⊢ Q (A * B)

Tactic:
exact ⟨by simp [QA.1, QB.1], hmul A B QA.1 QB.1 QA.2 QB.2⟩

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

Goal state before:
pp: R : Type u
inst✝ : CommRing R
f : R[X]
x y : R
⊢ eval (x + y) f = f.sum fun e a ↦ a * (x ^ e + ↑e * x ^ (e - 1) * y + ↑(polyBinomAux1 x y e a) * y ^ 2)

Tactic:
unfold eval; rw [eval₂_eq_sum]; congr with (n z)
  apply (polyBinomAux1 x y _ _).property

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

Goal state before:
pp: R : Type u_1
x y : R
inst✝ : Semiring R
h_comm : Commute x y
m n k : ℕ
hx : x ^ m = 0
hy : y ^ n = 0
h : m + n ≤ k + 1
⊢ (x + y) ^ k = 0

Tactic:
rw [h_comm.add_pow']
  apply Finset.sum_eq_zero
  rintro ⟨i, j⟩ hij
  suffices x ^ i * y ^ j = 0 by simp only [this, nsmul_eq_mul, mul_zero]
  by_cases hi : m ≤ i
  · rw [pow_eq_zero_of_le hi hx, zero_mul]
  rw [pow_eq_zero_of_le ?_ hy, mul_zero]
  linarith [Finset.mem_antidiagonal.mp hij]

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

Goal state before:
pp: case empty
R : Type u_1
inst✝ : Semiring R
ι : Type u_3
f : ι → R
hnp : ∀ i ∈ ∅, IsNilpotent (f i)
h_comm : ∀ (i j : ι), i ∈ ∅ → j ∈ ∅ → Commute (f i) (f j)
⊢ IsNilpotent (∑ i ∈ ∅, f i)

Tactic:
| empty =>

Goal state after:
Module: Mathlib.RingTheory.Finiteness.Subalgebra

Goal state before:
pp: R : Type u_1
A : Type u_2
inst✝² : CommSemiring R
inst✝¹ : Semiring A
inst✝ : Algebra R A
I : (Submodule R A)ˣ
⊢ (↑I).FG

Tactic:
obtain ⟨T, T', hT, hT', one_mem⟩ := mem_span_mul_finite_of_mem_mul (I.mul_inv ▸ one_le.mp le_rfl)
  refine ⟨T, span_eq_of_le _ hT ?_⟩
  rw [← one_mul I, ← mul_one (span R (T : Set A))]
  conv_rhs => rw [← I.inv_mul, ← mul_assoc]
  grw [← span_le.mpr hT', Units.val_mul, Units.val_one, span_mul_span, one_le.2 one_mem]

Goal state after:
Module: Mathlib.RingTheory.IntegralClosure.IsIntegral.Basic

Goal state before:
pp: case empty
R : Type u_1
A : Type u_2
inst✝² : CommRing R
inst✝¹ : CommRing A
inst✝ : Algebra R A
s : Set A
his : ∀ x ∈ ∅, IsIntegral R x
⊢ (Subalgebra.toSubmodule R[]).FG

Tactic:
| empty =>

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

Goal state before:
pp: R : Type u
inst✝¹ : Semiring R
S : Type v
inst✝ : Semiring S
f : R →+* S
p : S[X]
hlifts : ∀ (n : ℕ), p.coeff n ∈ Set.range ⇑f
g : ℕ → R := fun k ↦ Exists.choose ⋯
hg : ∀ (k : ℕ), f (g k) = p.coeff k
q : R[X] := ∑ k ∈ p.support, (monomial k) (g k)
⊢ ∑ x ∈ p.support, (monomial x) (p.coeff x) = p

Tactic:
← as_sum_support

Goal state after:
Module: Mathlib.RingTheory.IntegralClosure.Algebra.Basic

Goal state before:
pp: R : Type u_1
B : Type u_3
inst✝² : CommRing R
inst✝¹ : Ring B
inst✝ : Algebra R B
n : ℤ
⊢ IsIntegral R ↑n

Tactic:
← map_intCast (_ : R →+* B) n

Goal state after:
R : Type u_1
B : Type u_3
inst✝² : CommRing R
inst✝¹ : Ring B
inst✝ : Algebra R B
n : ℤ
⊢ IsIntegral R (?m.25 ↑n)

R : Type u_1
B : Type u_3
inst✝² : CommRing R
inst✝¹ : Ring B
inst✝ : Algebra R B
n : ℤ
⊢ R →+* B
Module: Mathlib.Algebra.Polynomial.HasseDeriv

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

Tactic:
mul_assoc

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

Goal state before:
pp: case pos
R : Type u_1
inst✝ : Semiring R
k l i : ℕ
hikl : i < k + l
hil : i < l
⊢ (i - l).choose k * i.choose l = 0

Tactic:
rw [choose_eq_zero_of_lt hil, mul_zero]

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

Goal state before:
pp: R : Type u_1
inst✝ : Semiring R
k l : ℕ
⊢ hasseDeriv k ∘ₗ hasseDeriv l = (k + l).choose k • hasseDeriv (k + l)

Tactic:
ext i : 2
  simp only [LinearMap.smul_apply, comp_apply, LinearMap.coe_comp, smul_monomial, hasseDeriv_apply,
    mul_one, monomial_eq_zero_iff, sum_monomial_index, mul_zero, ←
    tsub_add_eq_tsub_tsub, add_comm l k]
  rw_mod_cast [nsmul_eq_mul]
  rw [← Nat.cast_mul]
  congr 2
  by_cases! hikl : i < k + l
  · rw [choose_eq_zero_of_lt hikl, mul_zero]
    by_cases! hil : i < l
    · rw [choose_eq_zero_of_lt hil, mul_zero]
    · rw [← tsub_lt_iff_right hil] at hikl
      rw [choose_eq_zero_of_lt hikl, zero_mul]
  apply @cast_injective ℚ
  have h1 : l ≤ i := le_of_add_le_right hikl
  have h2 : k ≤ i - l := le_tsub_of_add_le_right hikl
  have h3 : k ≤ k + l := le_self_add
  push_cast
  rw [cast_choose ℚ h1, cast_choose ℚ h2, cast_choose ℚ h3, cast_choose ℚ hikl]
  rw [show i - (k + l) = i - l - k by rw [add_comm]; apply tsub_add_eq_tsub_tsub]
  simp only [add_tsub_cancel_left]
  field

Goal state after:
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
⊢ f (p.coeff i) * f s ^ (p.natDegree - i) * (f s ^ i * a ^ i) =
    f (p.coeff i) * (f s ^ (p.natDegree - i) * f s ^ i) * a ^ i

Tactic:
mul_assoc

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

Goal state before:
pp: case neg
R : Type u_1
inst✝ : Semiring R
D : ℕ → R[X] →+ R[X] := fun k ↦ (hasseDeriv k).toAddMonoidHom
Φ : R[X] →+ R[X] →+ R[X] := mul
m : ℕ
r : R
n : ℕ
s : R
x : ℕ × ℕ
hm : x.1 ≤ m
hn : x.2 ≤ n
⊢ (monomial (m + n - (x.1 + x.2))) (↑(m.choose x.1) * (↑(n.choose x.2) * (r * s))) =
    (monomial (m + n - (x.1 + x.2))) (↑(m.choose x.1) * ↑(n.choose x.2) * (r * s))

Tactic:
mul_assoc

Goal state after:
case neg
R : Type u_1
inst✝ : Semiring R
D : ℕ → R[X] →+ R[X] := fun k ↦ (hasseDeriv k).toAddMonoidHom
Φ : R[X] →+ R[X] →+ R[X] := mul
m : ℕ
r : R
n : ℕ
s : R
x : ℕ × ℕ
hm : x.1 ≤ m
hn : x.2 ≤ n
⊢ (monomial (m + n - (x.1 + x.2))) (↑(m.choose x.1) * (↑(n.choose x.2) * (r * s))) =
    (monomial (m + n - (x.1 + x.2))) (↑(m.choose x.1) * (↑(n.choose x.2) * (r * s)))