mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.LinearAlgebra.Lagrange

Goal state before:
pp: F : Type u_1
inst✝¹ : Field F
ι : Type u_2
inst✝ : DecidableEq ι
s : Finset ι
v : ι → F
i : ι
hvs : Set.InjOn v ↑s
hi : i ∈ s
j : ι
hj : j ∈ s.erase i
⊢ (v i - v j)⁻¹ ≠ 0

Tactic:
rcases mem_erase.mp hj with ⟨hij, hj⟩

Goal state after:
F : Type u_1
inst✝¹ : Field F
ι : Type u_2
inst✝ : DecidableEq ι
s : Finset ι
v : ι → F
i : ι
hvs : Set.InjOn v ↑s
hi : i ∈ s
j : ι
hj✝ : j ∈ s.erase i
hij : j ≠ i
hj : j ∈ s
⊢ (v i - v j)⁻¹ ≠ 0
Module: Mathlib.RingTheory.MvPolynomial.WeightedHomogeneous

Goal state before:
pp: R : Type u_1
M : Type u_2
inst✝¹ : CommSemiring R
σ : Type u_3
inst✝ : AddCommMonoid M
φ : MvPolynomial σ R
m : M
w : σ → M
hφ : IsWeightedHomogeneous w φ m
r : R
⊢ IsWeightedHomogeneous w (C r * φ) (0 + m)

Tactic:
exact (isWeightedHomogeneous_C w r).mul hφ

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

Goal state before:
pp: case zero
R : Type u_1
M : Type u_2
inst✝¹ : CommSemiring R
σ : Type u_3
inst✝ : AddCommMonoid M
φ : MvPolynomial σ R
m : M
w : σ → M
hφ : IsWeightedHomogeneous w φ m
⊢ IsWeightedHomogeneous w (φ ^ 0) (0 • m)

Tactic:
rw [pow_zero, zero_smul]; exact isWeightedHomogeneous_one R w

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

Goal state before:
pp: R : Type u_1
S : Type u_2
n : Type u_3
inst✝³ : CommRing R
inst✝² : CommRing S
inst✝¹ : Fintype n
inst✝ : DecidableEq n
f : R →+* S
M : n × n → S
i : ℕ
⊢ (MvPolynomial.eval₂Hom f M) ((univ R n).coeff i) = (Polynomial.map (MvPolynomial.eval₂Hom f M) (univ R n)).coeff i

Tactic:
Polynomial.coeff_map

Goal state after:
R : Type u_1
S : Type u_2
n : Type u_3
inst✝³ : CommRing R
inst✝² : CommRing S
inst✝¹ : Fintype n
inst✝ : DecidableEq n
f : R →+* S
M : n × n → S
i : ℕ
⊢ (MvPolynomial.eval₂Hom f M) ((univ R n).coeff i) = (MvPolynomial.eval₂Hom f M) ((univ R n).coeff i)
Module: Mathlib.RingTheory.GradedAlgebra.Homogeneous.Ideal

Goal state before:
pp: ι : Type u_1
σ : Type u_2
A : Type u_3
inst✝⁵ : Semiring A
inst✝⁴ : DecidableEq ι
inst✝³ : AddMonoid ι
inst✝² : SetLike σ A
inst✝¹ : AddSubmonoidClass σ A
𝒜 : ι → σ
inst✝ : GradedRing 𝒜
κ : Sort u_4
κ' : κ → Sort u_5
s : (i : κ) → κ' i → HomogeneousIdeal 𝒜
⊢ (⨅ i, ⨅ j, s i j).toIdeal = ⨅ i, ⨅ j, (s i j).toIdeal

Tactic:
simp_rw [toIdeal_iInf]

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

Goal state before:
pp: case pos
R : Type u_1
M : Type u_2
inst✝¹ : CommSemiring R
σ : Type u_3
inst✝ : AddCommMonoid M
w : σ → M
m : M
p : MvPolynomial σ R
hp : IsWeightedHomogeneous w p m
x : σ →₀ ℕ
zero_coeff : coeff x p = 0
⊢ (if (weight w) x = m then coeff x p else 0) = coeff x p

pp: case neg
R : Type u_1
M : Type u_2
inst✝¹ : CommSemiring R
σ : Type u_3
inst✝ : AddCommMonoid M
w : σ → M
m : M
p : MvPolynomial σ R
hp : IsWeightedHomogeneous w p m
x : σ →₀ ℕ
zero_coeff : ¬coeff x p = 0
⊢ (if (weight w) x = m then coeff x p else 0) = coeff x p

Tactic:
· split_ifs
    · rfl
    rw [zero_coeff]

Goal state after:
case neg
R : Type u_1
M : Type u_2
inst✝¹ : CommSemiring R
σ : Type u_3
inst✝ : AddCommMonoid M
w : σ → M
m : M
p : MvPolynomial σ R
hp : IsWeightedHomogeneous w p m
x : σ →₀ ℕ
zero_coeff : ¬coeff x p = 0
⊢ (if (weight w) x = m then coeff x p else 0) = coeff x p
Module: Mathlib.RingTheory.MvPolynomial.WeightedHomogeneous

Goal state before:
pp: R : Type u_1
M : Type u_2
inst✝² : CommSemiring R
σ : Type u_3
inst✝¹ : AddCommMonoid M
w : σ → M
inst✝ : DecidableEq M
n : M
p : MvPolynomial σ R
⊢ ((weightedHomogeneousComponent w n) p).support = {c ∈ p.support | (weight w) c = n}

Tactic:
ext c

Goal state after:
R : Type u_1
M : Type u_2
inst✝² : CommSemiring R
σ : Type u_3
inst✝¹ : AddCommMonoid M
w : σ → M
inst✝ : DecidableEq M
n : M
p : MvPolynomial σ R
c : σ →₀ ℕ
⊢ c ∈ ((weightedHomogeneousComponent w n) p).support ↔ c ∈ {c ∈ p.support | (weight w) c = n}
Module: Mathlib.RingTheory.MvPolynomial.WeightedHomogeneous

Goal state before:
pp: case inr.hnc
R : Type u_1
M : Type u_2
inst✝⁴ : CommSemiring R
σ : Type u_3
inst✝³ : AddCommMonoid M
inst✝² : PartialOrder M
w : σ → M
φ : MvPolynomial σ R
inst✝¹ : CanonicallyOrderedAdd M
inst✝ : IsAddTorsionFree M
hw : ∀ (i : σ), w i ≠ 0
d : σ →₀ ℕ
hd : ∃ x, ¬d x = 0
⊢ ∃ x, ¬d x = 0 ∧ ¬w x = 0

Tactic:
obtain ⟨i, hi⟩ := hd

Goal state after:
case inr.hnc
R : Type u_1
M : Type u_2
inst✝⁴ : CommSemiring R
σ : Type u_3
inst✝³ : AddCommMonoid M
inst✝² : PartialOrder M
w : σ → M
φ : MvPolynomial σ R
inst✝¹ : CanonicallyOrderedAdd M
inst✝ : IsAddTorsionFree M
hw : ∀ (i : σ), w i ≠ 0
d : σ →₀ ℕ
i : σ
hi : ¬d i = 0
⊢ ∃ x, ¬d x = 0 ∧ ¬w x = 0
Module: Mathlib.LinearAlgebra.Eigenspace.Zero

Goal state before:
pp: K : Type u_2
M : Type u_3
inst✝³ : Field K
inst✝² : AddCommGroup M
inst✝¹ : Module K M
inst✝ : Module.Finite K M
φ : End K M
V : Submodule K M := φ.maxGenEigenspace 0
hV : V = ⨆ n, ker (φ ^ n)
W : Submodule K M := ⨅ n, range (φ ^ n)
hVW : IsCompl V W
hφV : ∀ x ∈ V, φ x ∈ V
hφW : ∀ x ∈ W, φ x ∈ W
F : ↥V →ₗ[K] ↥V := restrict φ hφV
G : ↥W →ₗ[K] ↥W := restrict φ hφW
ψ : ↥V × ↥W →ₗ[K] ↥V × ↥W := F.prodMap G
e : (↥V × ↥W) ≃ₗ[K] M := V.prodEquivOfIsCompl W hVW
bV : Basis (ChooseBasisIndex K ↥V) K ↥V := chooseBasis K ↥V
⊢ finrank K ↥V = (charpoly φ).natTrailingDegree

Tactic:
let bW := chooseBasis K W

Goal state after:
K : Type u_2
M : Type u_3
inst✝³ : Field K
inst✝² : AddCommGroup M
inst✝¹ : Module K M
inst✝ : Module.Finite K M
φ : End K M
V : Submodule K M := φ.maxGenEigenspace 0
hV : V = ⨆ n, ker (φ ^ n)
W : Submodule K M := ⨅ n, range (φ ^ n)
hVW : IsCompl V W
hφV : ∀ x ∈ V, φ x ∈ V
hφW : ∀ x ∈ W, φ x ∈ W
F : ↥V →ₗ[K] ↥V := restrict φ hφV
G : ↥W →ₗ[K] ↥W := restrict φ hφW
ψ : ↥V × ↥W →ₗ[K] ↥V × ↥W := F.prodMap G
e : (↥V × ↥W) ≃ₗ[K] M := V.prodEquivOfIsCompl W hVW
bV : Basis (ChooseBasisIndex K ↥V) K ↥V := chooseBasis K ↥V
bW : Basis (ChooseBasisIndex K ↥W) K ↥W := chooseBasis K ↥W
⊢ finrank K ↥V = (charpoly φ).natTrailingDegree
Module: Mathlib.Algebra.Module.LinearMap.Polynomial

Goal state before:
pp: R : Type u_1
L : Type u_2
M : Type u_3
ι : Type u_5
ιM : Type u_7
inst✝¹⁰ : CommRing R
inst✝⁹ : AddCommGroup L
inst✝⁸ : Module R L
inst✝⁷ : AddCommGroup M
inst✝⁶ : Module R M
φ : L →ₗ[R] End R M
inst✝⁵ : Fintype ι
inst✝⁴ : Fintype ιM
inst✝³ : DecidableEq ι
inst✝² : DecidableEq ιM
b : Basis ι R L
bₘ : Basis ιM R M
inst✝¹ : Module.Finite R M
inst✝ : Free R M
x : L
i : ℕ
a✝ : Nontrivial R
⊢ (eval ⇑(b.repr x)) ((φ.polyCharpolyAux b bₘ).coeff i) =
    (Polynomial.map (eval ⇑(b.repr x)) (φ.polyCharpolyAux b bₘ)).coeff i

Tactic:
Polynomial.coeff_map

Goal state after:
R : Type u_1
L : Type u_2
M : Type u_3
ι : Type u_5
ιM : Type u_7
inst✝¹⁰ : CommRing R
inst✝⁹ : AddCommGroup L
inst✝⁸ : Module R L
inst✝⁷ : AddCommGroup M
inst✝⁶ : Module R M
φ : L →ₗ[R] End R M
inst✝⁵ : Fintype ι
inst✝⁴ : Fintype ιM
inst✝³ : DecidableEq ι
inst✝² : DecidableEq ιM
b : Basis ι R L
bₘ : Basis ιM R M
inst✝¹ : Module.Finite R M
inst✝ : Free R M
x : L
i : ℕ
a✝ : Nontrivial R
⊢ (eval ⇑(b.repr x)) ((φ.polyCharpolyAux b bₘ).coeff i) = (eval ⇑(b.repr x)) ((φ.polyCharpolyAux b bₘ).coeff i)
Module: Mathlib.LinearAlgebra.Eigenspace.Zero

Goal state before:
pp: K : Type u_2
M : Type u_3
inst✝³ : Field K
inst✝² : AddCommGroup M
inst✝¹ : Module K M
inst✝ : Module.Finite K M
φ : End K M
V : Submodule K M := ⋯
hV : V = ⨆ n, ker (φ ^ n)
W : Submodule K M := ⋯
hVW : IsCompl V W
hφV : ∀ x ∈ V, φ x ∈ V
hφW : ∀ x ∈ W, φ x ∈ W
F : ↥V →ₗ[K] ↥V := ⋯
G : ↥W →ₗ[K] ↥W := ⋯
ψ : ↥V × ↥W →ₗ[K] ↥V × ↥W := ⋯
e : (↥V × ↥W) ≃ₗ[K] M := ⋯
bV : Basis (ChooseBasisIndex K ↥V) K ↥V := ⋯
bW : Basis (ChooseBasisIndex K ↥W) K ↥W := ⋯
b : Basis (ChooseBasisIndex K ↥V ⊕ ChooseBasisIndex K ↥W) K (↥V × ↥W) := ⋯
hψ : ψ = e.symm.conj φ
x : ↥W
hx : G x = 0
⊢ ↑x = ↑0

Tactic:
suffices x.1 ∈ V ⊓ W by rwa [hVW.inf_eq_bot, Submodule.mem_bot] at this

Goal state after:
K : Type u_2
M : Type u_3
inst✝³ : Field K
inst✝² : AddCommGroup M
inst✝¹ : Module K M
inst✝ : Module.Finite K M
φ : End K M
V : Submodule K M := φ.maxGenEigenspace 0
hV : V = ⨆ n, ker (φ ^ n)
W : Submodule K M := ⨅ n, range (φ ^ n)
hVW : IsCompl V W
hφV : ∀ x ∈ V, φ x ∈ V
hφW : ∀ x ∈ W, φ x ∈ W
F : ↥V →ₗ[K] ↥V := restrict φ hφV
G : ↥W →ₗ[K] ↥W := restrict φ hφW
ψ : ↥V × ↥W →ₗ[K] ↥V × ↥W := F.prodMap G
e : (↥V × ↥W) ≃ₗ[K] M := V.prodEquivOfIsCompl W hVW
bV : Basis (ChooseBasisIndex K ↥V) K ↥V := chooseBasis K ↥V
bW : Basis (ChooseBasisIndex K ↥W) K ↥W := chooseBasis K ↥W
b : Basis (ChooseBasisIndex K ↥V ⊕ ChooseBasisIndex K ↥W) K (↥V × ↥W) := bV.prod bW
hψ : ψ = e.symm.conj φ
x : ↥W
hx : G x = 0
⊢ ↑x ∈ V ⊓ W
Module: Mathlib.Algebra.Module.LinearMap.Polynomial

Goal state before:
pp: R : Type u_1
L : Type u_2
M : Type u_3
ι : Type u_5
ι' : Type u_6
inst✝¹⁰ : CommRing R
inst✝⁹ : AddCommGroup L
inst✝⁸ : Module R L
inst✝⁷ : AddCommGroup M
inst✝⁶ : Module R M
φ : L →ₗ[R] End R M
inst✝⁵ : Fintype ι
inst✝⁴ : Fintype ι'
inst✝³ : DecidableEq ι
inst✝² : DecidableEq ι'
inst✝¹ : Free R M
inst✝ : Module.Finite R M
b : Basis ι R L
b' : Basis ι' R L
k : ℕ
H :
  (Polynomial.map (↑(bind₁ (toMvPolynomial b (Free.chooseBasis R M).end φ)))
          (charpoly.univ R (Free.ChooseBasisIndex R M))).coeff
      k =
    0
⊢ (Polynomial.map (↑(bind₁ (toMvPolynomial b' (Free.chooseBasis R M).end φ)))
          (charpoly.univ R (Free.ChooseBasisIndex R M))).coeff
      k =
    0

Tactic:
Polynomial.coeff_map

Goal state after:
R : Type u_1
L : Type u_2
M : Type u_3
ι : Type u_5
ι' : Type u_6
inst✝¹⁰ : CommRing R
inst✝⁹ : AddCommGroup L
inst✝⁸ : Module R L
inst✝⁷ : AddCommGroup M
inst✝⁶ : Module R M
φ : L →ₗ[R] End R M
inst✝⁵ : Fintype ι
inst✝⁴ : Fintype ι'
inst✝³ : DecidableEq ι
inst✝² : DecidableEq ι'
inst✝¹ : Free R M
inst✝ : Module.Finite R M
b : Basis ι R L
b' : Basis ι' R L
k : ℕ
H : ↑(bind₁ (toMvPolynomial b (Free.chooseBasis R M).end φ)) ((charpoly.univ R (Free.ChooseBasisIndex R M)).coeff k) = 0
⊢ ↑(bind₁ (toMvPolynomial b' (Free.chooseBasis R M).end φ)) ((charpoly.univ R (Free.ChooseBasisIndex R M)).coeff k) = 0
Module: Mathlib.Algebra.Module.LinearMap.Polynomial

Goal state before:
pp: case mp
R : Type u_1
L : Type u_2
M : Type u_3
ι : Type u_5
ι' : Type u_6
inst✝¹⁰ : CommRing R
inst✝⁹ : AddCommGroup L
inst✝⁸ : Module R L
inst✝⁷ : AddCommGroup M
inst✝⁶ : Module R M
φ : L →ₗ[R] End R M
inst✝⁵ : Fintype ι
inst✝⁴ : Fintype ι'
inst✝³ : DecidableEq ι
inst✝² : DecidableEq ι'
inst✝¹ : Free R M
inst✝ : Module.Finite R M
b : Basis ι R L
b' : Basis ι' R L
k : ℕ
⊢ (φ.polyCharpoly b).coeff k = 0 → (φ.polyCharpoly b').coeff k = 0

Tactic:
apply polyCharpoly_coeff_eq_zero_of_basis

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

Goal state before:
pp: case mpr
R : Type u_1
L : Type u_2
M : Type u_3
ι : Type u_5
ι' : Type u_6
inst✝¹⁰ : CommRing R
inst✝⁹ : AddCommGroup L
inst✝⁸ : Module R L
inst✝⁷ : AddCommGroup M
inst✝⁶ : Module R M
φ : L →ₗ[R] End R M
inst✝⁵ : Fintype ι
inst✝⁴ : Fintype ι'
inst✝³ : DecidableEq ι
inst✝² : DecidableEq ι'
inst✝¹ : Free R M
inst✝ : Module.Finite R M
b : Basis ι R L
b' : Basis ι' R L
k : ℕ
⊢ (φ.polyCharpoly b').coeff k = 0 → (φ.polyCharpoly b).coeff k = 0

Tactic:
apply polyCharpoly_coeff_eq_zero_of_basis

Goal state after:
Module: Mathlib.LinearAlgebra.Eigenspace.Zero

Goal state before:
pp: K : Type u_2
M : Type u_3
inst✝³ : Field K
inst✝² : AddCommGroup M
inst✝¹ : Module K M
inst✝ : Module.Finite K M
φ : End K M
μ : K
k : ℕ
⊢ finrank K ↥((φ.genEigenspace μ) ↑k) ≤ rootMultiplicity μ (charpoly φ)

Tactic:
by
  grw [Submodule.finrank_mono (φ.genEigenspace_le_maximal μ k), finrank_maxGenEigenspace_eq]

Goal state after:
Module: Mathlib.Algebra.Lie.Classical

Goal state before:
pp: case inr.inr
p : Type u_2
q : Type u_3
R : Type u₂
inst✝⁴ : DecidableEq p
inst✝³ : DecidableEq q
inst✝² : CommRing R
inst✝¹ : Fintype p
inst✝ : Fintype q
i : R
hi : i * i = -1
x y : q
⊢ (Pso p q R i * Pso p q R (-i)) (Sum.inr x) (Sum.inr y) = 1 (Sum.inr x) (Sum.inr y)

Tactic:
by_cases h : x = y <;>
    simp [Pso, h, hi, one_apply]

Goal state after:
Module: Mathlib.LinearAlgebra.SymplecticGroup

Goal state before:
pp: l : Type u_1
R : Type u_2
inst✝² : DecidableEq l
inst✝¹ : Fintype l
inst✝ : CommRing R
A : Matrix (l ⊕ l) (l ⊕ l) R
hA : A * J l R * Aᵀ = J l R
⊢ Aᵀ * J l R * Aᵀᵀ = J l R

Tactic:
transpose_transpose

Goal state after:
l : Type u_1
R : Type u_2
inst✝² : DecidableEq l
inst✝¹ : Fintype l
inst✝ : CommRing R
A : Matrix (l ⊕ l) (l ⊕ l) R
hA : A * J l R * Aᵀ = J l R
⊢ Aᵀ * J l R * A = J l R
Module: Mathlib.LinearAlgebra.SymplecticGroup

Goal state before:
pp: l : Type u_1
R : Type u_2
inst✝² : DecidableEq l
inst✝¹ : Fintype l
inst✝ : CommRing R
A : Matrix (l ⊕ l) (l ⊕ l) R
⊢ Aᵀ * J l R * Aᵀᵀ = J l R ↔ Aᵀ * J l R * A = J l R

Tactic:
transpose_transpose

Goal state after:
l : Type u_1
R : Type u_2
inst✝² : DecidableEq l
inst✝¹ : Fintype l
inst✝ : CommRing R
A : Matrix (l ⊕ l) (l ⊕ l) R
⊢ Aᵀ * J l R * A = J l R ↔ Aᵀ * J l R * A = J l R
Module: Mathlib.LinearAlgebra.SymplecticGroup

Goal state before:
pp: l : Type u_1
R : Type u_2
inst✝² : DecidableEq l
inst✝¹ : Fintype l
inst✝ : CommRing R
A B C D : Matrix l l R
h : Aᵀ * C = Cᵀ * A ∧ Bᵀ * D = Dᵀ * B ∧ Aᵀ * D - Cᵀ * B = 1
⊢ Dᵀ * A - Bᵀ * C = 1

Tactic:
by simpa using congr(transpose $(h.2.2))

Goal state after:
Module: Mathlib.Algebra.Lie.CartanExists

Goal state before:
pp: K : Type u_1
L : Type u_2
inst✝³ : Field K
inst✝² : LieRing L
inst✝¹ : LieAlgebra K L
inst✝ : Module.Finite K L
hLK : ↑(finrank K L) ≤ #K
U : LieSubalgebra K L
x : L
hxU : x ∈ U
y : L
hyU : y ∈ U
Ex : ↑{x | ∃ x_1 ∈ U, engel K x_1 = x} := ⟨engel K x, ⋯⟩
Ey : ↑{x | ∃ y ∈ U, engel K y = x} := ⟨engel K y, ⋯⟩
hUle : U ≤ ↑Ex
hmin : ∀ E ≤ Ex, Ex ≤ E
E : LieSubmodule K (↥U) L :=
  let __src := engel K x;
  { toSubmodule := __src.toSubmodule, lie_mem := ⋯ }
hx₀ : x ≠ 0
Q : Type u_2 := L ⧸ E
r : ℕ := finrank K ↥E
hr : r < finrank K L
x' : ↥U := ⟨x, hxU⟩
y' : ↥U := ⟨y, hyU⟩
u : ↥U := y' - x'
χ : K[X][X] := lieCharpoly K (↥E) x' u
ψ : K[X][X] := lieCharpoly K Q x' u
hi : 0 < r
α : K
⊢ ∃ m, m ≠ 0 ∧ ((toEnd K ↥U ↥E) (α • u + x')) m = 0

Tactic:
let z := α • u + x'

Goal state after:
K : Type u_1
L : Type u_2
inst✝³ : Field K
inst✝² : LieRing L
inst✝¹ : LieAlgebra K L
inst✝ : Module.Finite K L
hLK : ↑(finrank K L) ≤ #K
U : LieSubalgebra K L
x : L
hxU : x ∈ U
y : L
hyU : y ∈ U
Ex : ↑{x | ∃ x_1 ∈ U, engel K x_1 = x} := ⟨engel K x, ⋯⟩
Ey : ↑{x | ∃ y ∈ U, engel K y = x} := ⟨engel K y, ⋯⟩
hUle : U ≤ ↑Ex
hmin : ∀ E ≤ Ex, Ex ≤ E
E : LieSubmodule K (↥U) L :=
  let __src := engel K x;
  { toSubmodule := __src.toSubmodule, lie_mem := ⋯ }
hx₀ : x ≠ 0
Q : Type u_2 := L ⧸ E
r : ℕ := finrank K ↥E
hr : r < finrank K L
x' : ↥U := ⟨x, hxU⟩
y' : ↥U := ⟨y, hyU⟩
u : ↥U := y' - x'
χ : K[X][X] := lieCharpoly K (↥E) x' u
ψ : K[X][X] := lieCharpoly K Q x' u
hi : 0 < r
α : K
z : ↥U := α • u + x'
⊢ ∃ m, m ≠ 0 ∧ ((toEnd K ↥U ↥E) (α • u + x')) m = 0
Module: Mathlib.LinearAlgebra.Matrix.Rank

Goal state before:
pp: m : Type um
n : Type un
inst✝² : Fintype n
R : Type u_1
inst✝¹ : CommRing R
inst✝ : DecidableEq n
A : Matrix n n R
B : Matrix m n R
hA : A.det ∈ nonZeroDivisors R
⊢ (B * A).rank = B.rank

Tactic:
nontriviality R
  refine le_antisymm (rank_mul_le_left B A) ?_
  have key : (B * A) * A.adjugate = A.det • B := by
    rw [Matrix.mul_assoc, Matrix.mul_adjugate, Matrix.mul_smul, Matrix.mul_one]
  calc B.rank = (A.det • B).rank := (rank_smul_of_mem_nonZeroDivisors B hA).symm
    _ = ((B * A) * A.adjugate).rank := by rw [key]
    _ ≤ (B * A).rank := rank_mul_le_left _ _

Goal state after:
Module: Mathlib.LinearAlgebra.SymplecticGroup

Goal state before:
pp: l : Type u_1
inst✝² : DecidableEq l
inst✝¹ : Fintype l
R : Type u_3
inst✝ : Field R
A C : Matrix l l R
hker : ∀ (x : l → R), A • x = 0 → C • x = 0 → x = 0
hsymm : Aᵀ * C = Cᵀ * A
V U : Matrix l l R
s : l ≃ Fin C.rank ⊕ Fin (Fintype.card l - C.rank)
hV : IsUnit V
hU : IsUnit U
P : Matrix l l R := V * C * U
heq : P = (fromBlocks 1 0 0 0).submatrix ⇑s ⇑s
P_def : P = V * C * U
Q : Matrix l l R := Vᵀ⁻¹ * A * U
Q_def : Q = Vᵀ⁻¹ * A * U
f : Matrix l l R → Matrix (Fin C.rank ⊕ Fin (Fintype.card l - C.rank)) (Fin C.rank ⊕ Fin (Fintype.card l - C.rank)) R :=
  fun x ↦ x.submatrix ⇑s.symm ⇑s.symm
hf : ∀ (x : Matrix l l R), f x = x.submatrix ⇑s.symm ⇑s.symm
f_unit : ∀ {x : Matrix l l R}, IsUnit x → IsUnit (f x)
f_mul : ∀ (x y : Matrix l l R), f (x * y) = f x * f y
x✝² : Invertible V
x✝¹ : Invertible U
x✝ : Invertible (f Vᵀ)
con1 : ∀ (x : Fin C.rank ⊕ Fin (Fintype.card l - C.rank) → R), f Q • x = 0 → f P • x = 0 → x = 0
⊢ Qᵀ * P = Pᵀ * Q

Tactic:
simp only [P_def, mul_assoc, transpose_mul, transpose_nonsing_inv, transpose_transpose, Q_def,
      inv_mul_cancel_left_of_invertible, mul_inv_cancel_left_of_invertible]

Goal state after:
l : Type u_1
inst✝² : DecidableEq l
inst✝¹ : Fintype l
R : Type u_3
inst✝ : Field R
A C : Matrix l l R
hker : ∀ (x : l → R), A • x = 0 → C • x = 0 → x = 0
hsymm : Aᵀ * C = Cᵀ * A
V U : Matrix l l R
s : l ≃ Fin C.rank ⊕ Fin (Fintype.card l - C.rank)
hV : IsUnit V
hU : IsUnit U
P : Matrix l l R := V * C * U
heq : P = (fromBlocks 1 0 0 0).submatrix ⇑s ⇑s
P_def : P = V * C * U
Q : Matrix l l R := Vᵀ⁻¹ * A * U
Q_def : Q = Vᵀ⁻¹ * A * U
f : Matrix l l R → Matrix (Fin C.rank ⊕ Fin (Fintype.card l - C.rank)) (Fin C.rank ⊕ Fin (Fintype.card l - C.rank)) R :=
  fun x ↦ x.submatrix ⇑s.symm ⇑s.symm
hf : ∀ (x : Matrix l l R), f x = x.submatrix ⇑s.symm ⇑s.symm
f_unit : ∀ {x : Matrix l l R}, IsUnit x → IsUnit (f x)
f_mul : ∀ (x y : Matrix l l R), f (x * y) = f x * f y
x✝² : Invertible V
x✝¹ : Invertible U
x✝ : Invertible (f Vᵀ)
con1 : ∀ (x : Fin C.rank ⊕ Fin (Fintype.card l - C.rank) → R), f Q • x = 0 → f P • x = 0 → x = 0
⊢ Uᵀ * (Aᵀ * (C * U)) = Uᵀ * (Cᵀ * (A * U))
Module: Mathlib.Algebra.Lie.CartanExists

Goal state before:
pp: case h.refine_2
K : Type u_1
L : Type u_2
inst✝³ : Field K
inst✝² : LieRing L
inst✝¹ : LieAlgebra K L
inst✝ : Module.Finite K L
hLK : ↑(finrank K L) ≤ #K
U : LieSubalgebra K L
x : L
hxU : x ∈ U
y : L
hyU : y ∈ U
Ex : ↑{x | ∃ x_1 ∈ U, engel K x_1 = x} := ⟨engel K x, ⋯⟩
Ey : ↑{x | ∃ y ∈ U, engel K y = x} := ⟨engel K y, ⋯⟩
hUle : U ≤ ↑Ex
hmin : ∀ E ≤ Ex, Ex ≤ E
E : LieSubmodule K (↥U) L :=
  let __src := engel K x;
  { toSubmodule := __src.toSubmodule, lie_mem := ⋯ }
hx₀ : x ≠ 0
Q : Type u_2 := L ⧸ E
r : ℕ := finrank K ↥E
hr : r < finrank K L
x' : ↥U := ⟨x, hxU⟩
y' : ↥U := ⟨y, hyU⟩
u : ↥U := y' - x'
χ : K[X][X] := lieCharpoly K (↥E) x' u
ψ : K[X][X] := lieCharpoly K Q x' u
i : ℕ
hi : i < r
hi0 : i ≠ 0
hψ : constantCoeff ψ ≠ 0
t : Finset K := (constantCoeff ψ).roots.toFinset
ht : t.card ≤ finrank K L - r
s : Finset K
hs : finrank K L ≤ s.card
⊢ ∀ α ∈ s \ t, eval α (constantCoeff ψ) ≠ 0

Tactic:
· intro α hα
      simp only [Finset.mem_sdiff, Multiset.mem_toFinset, mem_roots', IsRoot.def, not_and, t] at hα
      exact hα.2 hψ

Goal state after:
Module: Mathlib.Algebra.Lie.CartanExists

Goal state before:
pp: K : Type u_1
L : Type u_2
inst✝³ : Field K
inst✝² : LieRing L
inst✝¹ : LieAlgebra K L
inst✝ : Module.Finite K L
hLK : ↑(finrank K L) ≤ #K
U : LieSubalgebra K L
x : L
hxU : x ∈ U
y : L
hyU : y ∈ U
Ex : ↑{x | ∃ x_1 ∈ U, engel K x_1 = x} := ⟨engel K x, ⋯⟩
Ey : ↑{x | ∃ y ∈ U, engel K y = x} := ⟨engel K y, ⋯⟩
hUle : U ≤ ↑Ex
hmin : ∀ E ≤ Ex, Ex ≤ E
E : LieSubmodule K (↥U) L :=
  let __src := engel K x;
  { toSubmodule := __src.toSubmodule, lie_mem := ⋯ }
hx₀ : x ≠ 0
Q : Type u_2 := L ⧸ E
r : ℕ := finrank K ↥E
hr : r < finrank K L
x' : ↥U := ⟨x, hxU⟩
y' : ↥U := ⟨y, hyU⟩
u : ↥U := y' - x'
χ : K[X][X] := lieCharpoly K (↥E) x' u
ψ : K[X][X] := lieCharpoly K Q x' u
i : ℕ
hi : i < r
hi0 : i ≠ 0
hψ : constantCoeff ψ ≠ 0
s : Finset K
hs : r ≤ s.card
hsψ : ∀ α ∈ s, eval α (constantCoeff ψ) ≠ 0
α : K
hα : α ∈ s
v : ↥U := α • u + x'
this : engel K ↑v ≤ engel K x
⊢ ∀ (m : ↥E), ∃ n, ((toEnd K ↥U ↥E) (α • u + x') ^ n) m = 0

Tactic:
by
    -- Indeed, in that case the minimality assumption on `E` implies
    -- that `E` is contained in the Engel subalgebra of `v`.
    replace this : engel K x ≤ engel K (v : L) := (hmin ⟨_, v, v.2, rfl⟩ this).ge
    intro z
    -- And so we are done, by the definition of Engel subalgebra.
    simpa only [mem_engel_iff, Subtype.ext_iff, coe_toEnd_pow _ _ _ E] using! this z.2

Goal state after:
Module: Mathlib.RingTheory.Derivation.Lie

Goal state before:
pp: R : Type u_1
inst✝² : CommRing R
A : Type u_2
inst✝¹ : CommRing A
inst✝ : Algebra R A
D1✝ D2✝ : Derivation R A A
a✝ : A
D1 D2 : Derivation R A A
a b : A
⊢ ⁅↑D1, ↑D2⁆ (a * b) = a • ⁅↑D1, ↑D2⁆ b + b • ⁅↑D1, ↑D2⁆ a

Tactic:
simp only [Ring.lie_def, map_add, smul_eq_mul, Module.End.mul_apply, leibniz,
        coeFn_coe, LinearMap.sub_apply]
      ring

Goal state after:
Module: Mathlib.Algebra.Lie.DirectSum

Goal state before:
pp: R : Type u
ι : Type v
inst✝² : CommRing R
L : ι → Type w
inst✝¹ : (i : ι) → LieRing (L i)
inst✝ : (i : ι) → LieAlgebra R (L i)
x : ⨁ (i : ι), L i
i✝ : ι
⊢ (zipWith (fun x x_1 y ↦ ⁅x_1, y⁆) ⋯ x x) i✝ = 0 i✝

Tactic:
simp only [zipWith_apply, lie_self, zero_apply]

Goal state after:
Module: Mathlib.LinearAlgebra.SymplecticGroup

Goal state before:
pp: l : Type u_1
R : Type u_2
inst✝³ : DecidableEq l
inst✝² : Fintype l
inst✝¹ : CommRing R
inst✝ : IsLocalRing R
M : Matrix (l ⊕ l) (l ⊕ l) R
hM : M ∈ symplecticGroup l R
A : Matrix l l R := M.toBlocks₁₁
B : Matrix l l R := M.toBlocks₁₂
C : Matrix l l R := M.toBlocks₂₁
D : Matrix l l R := M.toBlocks₂₂
X : Matrix l l R
hX_symm : X.IsSymm
hA_isUnit : IsUnit (M.toBlocks₁₁ + X * M.toBlocks₂₁).det
Lx_mul : fromBlocks 1 X 0 1 * M = fromBlocks (A + X * C) (B + X * D) C D
⊢ fromBlocks 1 X 0 1 * M ∈ symplecticGroup l R

Tactic:
refine (symplecticGroup l R).mul_mem ?_ hM

Goal state after:
l : Type u_1
R : Type u_2
inst✝³ : DecidableEq l
inst✝² : Fintype l
inst✝¹ : CommRing R
inst✝ : IsLocalRing R
M : Matrix (l ⊕ l) (l ⊕ l) R
hM : M ∈ symplecticGroup l R
A : Matrix l l R := M.toBlocks₁₁
B : Matrix l l R := M.toBlocks₁₂
C : Matrix l l R := M.toBlocks₂₁
D : Matrix l l R := M.toBlocks₂₂
X : Matrix l l R
hX_symm : X.IsSymm
hA_isUnit : IsUnit (M.toBlocks₁₁ + X * M.toBlocks₂₁).det
Lx_mul : fromBlocks 1 X 0 1 * M = fromBlocks (A + X * C) (B + X * D) C D
⊢ fromBlocks 1 X 0 1 ∈ symplecticGroup l R
Module: Mathlib.Algebra.Lie.Free

Goal state before:
pp: R : Type u
X : Type v
inst✝ : CommRing R
⊢ Inhabited (FreeLieAlgebra R X)

Tactic:
rw [FreeLieAlgebra]; infer_instance

Goal state after:
Module: Mathlib.Algebra.Lie.LieTheorem

Goal state before:
pp: R : Type u_1
L : Type u_2
A : Type u_3
V : Type u_4
inst✝¹⁹ : CommRing R
inst✝¹⁸ : IsPrincipalIdealRing R
inst✝¹⁷ : IsDomain R
inst✝¹⁶ : CharZero R
inst✝¹⁵ : LieRing L
inst✝¹⁴ : LieAlgebra R L
inst✝¹³ : LieRing A
inst✝¹² : LieAlgebra R A
inst✝¹¹ : Bracket L A
inst✝¹⁰ : Bracket A L
inst✝⁹ : AddCommGroup V
inst✝⁸ : Module R V
inst✝⁷ : Module.Free R V
inst✝⁶ : Module.Finite R V
inst✝⁵ : LieRingModule L V
inst✝⁴ : LieModule R L V
inst✝³ : LieRingModule A V
inst✝² : LieModule R A V
inst✝¹ : IsLieTower L A V
inst✝ : IsLieTower A L V
χ : A → R
z : L
v : V
hv : ∀ (x : A), ⁅x, v⁆ = χ x • v
a : A
hv' : v ≠ 0
U' : ℕ →o Submodule R V :=
  { toFun := fun n ↦ Submodule.span R {x | ∃ i < n, ((toEnd R L V) z ^ i) v = x}, monotone' := ⋯ }
map_U'_le : ∀ (n : ℕ), Submodule.map ((toEnd R L V) z) (U' n) ≤ U' (n + 1)
w : A
n : ℕ
⊢ {x | ∃ i < n + 1, ((toEnd R L V) z ^ i) v = x} ⊆
    ⇑(T χ w) ⁻¹' ↑(Submodule.span R {x | ∃ i < n, ((toEnd R L V) z ^ i) v = x})

Tactic:
simp only [Set.subset_def, Set.mem_ofPred_eq, Set.mem_preimage, SetLike.mem_coe,
      forall_exists_index, and_imp, forall_apply_eq_imp_iff₂]

Goal state after:
R : Type u_1
L : Type u_2
A : Type u_3
V : Type u_4
inst✝¹⁹ : CommRing R
inst✝¹⁸ : IsPrincipalIdealRing R
inst✝¹⁷ : IsDomain R
inst✝¹⁶ : CharZero R
inst✝¹⁵ : LieRing L
inst✝¹⁴ : LieAlgebra R L
inst✝¹³ : LieRing A
inst✝¹² : LieAlgebra R A
inst✝¹¹ : Bracket L A
inst✝¹⁰ : Bracket A L
inst✝⁹ : AddCommGroup V
inst✝⁸ : Module R V
inst✝⁷ : Module.Free R V
inst✝⁶ : Module.Finite R V
inst✝⁵ : LieRingModule L V
inst✝⁴ : LieModule R L V
inst✝³ : LieRingModule A V
inst✝² : LieModule R A V
inst✝¹ : IsLieTower L A V
inst✝ : IsLieTower A L V
χ : A → R
z : L
v : V
hv : ∀ (x : A), ⁅x, v⁆ = χ x • v
a : A
hv' : v ≠ 0
U' : ℕ →o Submodule R V :=
  { toFun := fun n ↦ Submodule.span R {x | ∃ i < n, ((toEnd R L V) z ^ i) v = x}, monotone' := ⋯ }
map_U'_le : ∀ (n : ℕ), Submodule.map ((toEnd R L V) z) (U' n) ≤ U' (n + 1)
w : A
n : ℕ
⊢ ∀ a < n + 1, (T χ w) (((toEnd R L V) z ^ a) v) ∈ Submodule.span R {x | ∃ i < n, ((toEnd R L V) z ^ i) v = x}