mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.Data.Matrix.Block

Goal state before:
pp: m : Type u_2
n : Type u_3
o : Type u_4
α : Type u_12
inst✝¹ : DecidableEq o
inst✝ : Zero α
M : o → Matrix m n α
i✝ : n × o
j✝ : m × o
⊢ (if i✝.2 = j✝.2 then M i✝.2 j✝.1 i✝.1 else 0) = if i✝.2 = j✝.2 then M j✝.2 j✝.1 i✝.1 else 0

Tactic:
split_ifs with h

Goal state after:
case pos
m : Type u_2
n : Type u_3
o : Type u_4
α : Type u_12
inst✝¹ : DecidableEq o
inst✝ : Zero α
M : o → Matrix m n α
i✝ : n × o
j✝ : m × o
h : i✝.2 = j✝.2
⊢ M i✝.2 j✝.1 i✝.1 = M j✝.2 j✝.1 i✝.1

case neg
m : Type u_2
n : Type u_3
o : Type u_4
α : Type u_12
inst✝¹ : DecidableEq o
inst✝ : Zero α
M : o → Matrix m n α
i✝ : n × o
j✝ : m × o
h : ¬i✝.2 = j✝.2
⊢ 0 = 0
Module: Mathlib.Data.Matrix.Block

Goal state before:
pp: m : Type u_2
n : Type u_3
o : Type u_4
p : Type u_5
α : Type u_12
inst✝³ : DecidableEq o
inst✝² : Fintype n
inst✝¹ : Fintype o
inst✝ : NonUnitalNonAssocSemiring α
M : o → Matrix m n α
N : o → Matrix n p α
i : m
k : o
j : p
k' : o
⊢ (if k = k' then ∑ j_1, M k i j_1 * N k j_1 j else 0) =
    ∑ x, ∑ x_1, (if k = x_1 then M k i x else 0) * if x_1 = k' then N x_1 x j else 0

Tactic:
split_ifs with h

Goal state after:
case pos
m : Type u_2
n : Type u_3
o : Type u_4
p : Type u_5
α : Type u_12
inst✝³ : DecidableEq o
inst✝² : Fintype n
inst✝¹ : Fintype o
inst✝ : NonUnitalNonAssocSemiring α
M : o → Matrix m n α
N : o → Matrix n p α
i : m
k : o
j : p
k' : o
h : k = k'
⊢ ∑ j_1, M k i j_1 * N k j_1 j = ∑ x, ∑ x_1, (if k = x_1 then M k i x else 0) * if x_1 = k' then N x_1 x j else 0

case neg
m : Type u_2
n : Type u_3
o : Type u_4
p : Type u_5
α : Type u_12
inst✝³ : DecidableEq o
inst✝² : Fintype n
inst✝¹ : Fintype o
inst✝ : NonUnitalNonAssocSemiring α
M : o → Matrix m n α
N : o → Matrix n p α
i : m
k : o
j : p
k' : o
h : ¬k = k'
⊢ 0 = ∑ x, ∑ x_1, (if k = x_1 then M k i x else 0) * if x_1 = k' then N x_1 x j else 0
Module: Mathlib.RingTheory.OreLocalization.Basic

Goal state before:
pp: case h
R : Type u_1
inst✝³ : Monoid R
S : Submonoid R
inst✝² : OreSet S
X : Type u_2
inst✝¹ : AddMonoid X
inst✝ : DistribMulAction R X
r₂ : X
s₂ : ↥S
r₁' : X
s₁' : ↥S
r₁ : X
s₁ sb : ↥S
rb : R
hb : sb • r₁ = rb • r₁'
hb' : ↑sb * ↑s₁ = rb * ↑s₁'
rc : R
sc : ↥S
hc : ↑sc * ↑s₁' = rc * ↑s₂
rd : R
sd : ↥S
hd : ↑sd * rb = rd * ↑sc
this : ↑sd * ↑sb * ↑s₁ = rd * rc * ↑s₂
⊢ ∃ v,
    1 • ((rd * ↑sc) • r₁' + (rd * rc) • r₂) = v • (↑sc • r₁' + rc • r₂) ∧
      ↑1 * ↑⟨↑sd * ↑sb * ↑s₁, ⋯⟩ = v * ↑⟨↑sc * ↑s₁', ⋯⟩

Tactic:
use rd

Goal state after:
case h
R : Type u_1
inst✝³ : Monoid R
S : Submonoid R
inst✝² : OreSet S
X : Type u_2
inst✝¹ : AddMonoid X
inst✝ : DistribMulAction R X
r₂ : X
s₂ : ↥S
r₁' : X
s₁' : ↥S
r₁ : X
s₁ sb : ↥S
rb : R
hb : sb • r₁ = rb • r₁'
hb' : ↑sb * ↑s₁ = rb * ↑s₁'
rc : R
sc : ↥S
hc : ↑sc * ↑s₁' = rc * ↑s₂
rd : R
sd : ↥S
hd : ↑sd * rb = rd * ↑sc
this : ↑sd * ↑sb * ↑s₁ = rd * rc * ↑s₂
⊢ 1 • ((rd * ↑sc) • r₁' + (rd * rc) • r₂) = rd • (↑sc • r₁' + rc • r₂) ∧
    ↑1 * ↑⟨↑sd * ↑sb * ↑s₁, ⋯⟩ = rd * ↑⟨↑sc * ↑s₁', ⋯⟩
Module: Mathlib.LinearAlgebra.Matrix.ToLin

Goal state before:
pp: R : Type u_1
inst✝⁴ : Semiring R
l : Type u_2
m : Type u_3
n : Type u_4
inst✝³ : Fintype m
inst✝² : DecidableEq m
inst✝¹ : Fintype n
inst✝ : DecidableEq n
M : Matrix m n R
M' : Matrix n m R
hMM' : M * M' = 1
hM'M : M' * M = 1
x : n → R
⊢ (toLinearMapRight' M) ((toLinearMapRight' M') x) = x

Tactic:
rw [← Matrix.toLinearMapRight'_mul_apply, hM'M, Matrix.toLinearMapRight'_one, id_apply]

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

Goal state before:
pp: R : Type u_1
inst✝⁷ : CommSemiring R
m : Type u_3
n : Type u_4
inst✝⁶ : Fintype n
inst✝⁵ : DecidableEq n
M₁ : Type u_5
M₂ : Type u_6
inst✝⁴ : AddCommMonoid M₁
inst✝³ : AddCommMonoid M₂
inst✝² : Module R M₁
inst✝¹ : Module R M₂
v₁ : Basis n R M₁
v₂ : Basis m R M₂
inst✝ : Fintype m
M : Matrix m n R
v : M₁
⊢ v₂.equivFun.symm (M *ᵥ ⇑(v₁.repr v)) = ∑ j, (M *ᵥ ⇑(v₁.repr v)) j • v₂ j

Tactic:
v₂.equivFun_symm_apply

Goal state after:
R : Type u_1
inst✝⁷ : CommSemiring R
m : Type u_3
n : Type u_4
inst✝⁶ : Fintype n
inst✝⁵ : DecidableEq n
M₁ : Type u_5
M₂ : Type u_6
inst✝⁴ : AddCommMonoid M₁
inst✝³ : AddCommMonoid M₂
inst✝² : Module R M₁
inst✝¹ : Module R M₂
v₁ : Basis n R M₁
v₂ : Basis m R M₂
inst✝ : Fintype m
M : Matrix m n R
v : M₁
⊢ ∑ i, (M *ᵥ ⇑(v₁.repr v)) i • v₂ i = ∑ j, (M *ᵥ ⇑(v₁.repr v)) j • v₂ j
Module: Mathlib.GroupTheory.MonoidLocalization.MonoidWithZero

Goal state before:
pp: M : Type u_1
inst✝² : CommMonoidWithZero M
S : Submonoid M
N : Type u_2
inst✝¹ : CommMonoidWithZero N
P : Type u_3
inst✝ : CommMonoidWithZero P
x : Localization S
y : M × ↥S
⊢ 0 * mk y.1 y.2 = 0

Tactic:
simp only [← Localization.mk_zero y.2, mk_mul, mk_eq_mk_iff, mul_zero, zero_mul, r_of_eq]

Goal state after:
Module: Mathlib.RingTheory.OreLocalization.Ring

Goal state before:
pp: R : Type u_1
inst✝³ : Semiring R
S : Submonoid R
inst✝² : OreSet S
X : Type u_2
inst✝¹ : AddCommMonoid X
inst✝ : Module R X
x : OreLocalization S X
⊢ 0 • x = 0

Tactic:
by
  induction x with | _ r s
  rw [OreLocalization.zero_def, oreDiv_smul_char 0 r 1 s 0 1 (by simp)]; simp

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

Goal state before:
pp: R : Type u_1
S : Type u_2
T : Type u_3
inst✝¹⁰ : CommSemiring R
inst✝⁹ : CommSemiring S
inst✝⁸ : Semiring T
inst✝⁷ : Algebra R S
inst✝⁶ : Algebra S T
inst✝⁵ : Algebra R T
inst✝⁴ : IsScalarTower R S T
m : Type u_4
n : Type u_5
inst✝³ : Fintype m
inst✝² : Fintype n
inst✝¹ : DecidableEq m
inst✝ : DecidableEq n
b : Basis m R S
c : Basis n S T
x : S
i : m
k : n
j : m
k' : n
⊢ (leftMulMatrix b) (if (i, k).2 = (j, k').2 then (algebraMap S S) x else 0) (i, k).1 (j, k').1 =
    if (i, k).2 = (j, k').2 then (leftMulMatrix b) x (i, k).1 (j, k').1 else 0

Tactic:
split_ifs with h

Goal state after:
case pos
R : Type u_1
S : Type u_2
T : Type u_3
inst✝¹⁰ : CommSemiring R
inst✝⁹ : CommSemiring S
inst✝⁸ : Semiring T
inst✝⁷ : Algebra R S
inst✝⁶ : Algebra S T
inst✝⁵ : Algebra R T
inst✝⁴ : IsScalarTower R S T
m : Type u_4
n : Type u_5
inst✝³ : Fintype m
inst✝² : Fintype n
inst✝¹ : DecidableEq m
inst✝ : DecidableEq n
b : Basis m R S
c : Basis n S T
x : S
i : m
k : n
j : m
k' : n
h : (i, k).2 = (j, k').2
⊢ (leftMulMatrix b) ((algebraMap S S) x) (i, k).1 (j, k').1 = (leftMulMatrix b) x (i, k).1 (j, k').1

case neg
R : Type u_1
S : Type u_2
T : Type u_3
inst✝¹⁰ : CommSemiring R
inst✝⁹ : CommSemiring S
inst✝⁸ : Semiring T
inst✝⁷ : Algebra R S
inst✝⁶ : Algebra S T
inst✝⁵ : Algebra R T
inst✝⁴ : IsScalarTower R S T
m : Type u_4
n : Type u_5
inst✝³ : Fintype m
inst✝² : Fintype n
inst✝¹ : DecidableEq m
inst✝ : DecidableEq n
b : Basis m R S
c : Basis n S T
x : S
i : m
k : n
j : m
k' : n
h : ¬(i, k).2 = (j, k').2
⊢ (leftMulMatrix b) 0 (i, k).1 (j, k').1 = 0
Module: Mathlib.LinearAlgebra.FreeModule.PID

Goal state before:
pp: ι : Type u_1
R : Type u_2
inst✝⁶ : CommRing R
M : Type u_3
inst✝⁵ : AddCommGroup M
inst✝⁴ : Module R M
b : ι → M
inst✝³ : IsPrincipalIdealRing R
inst✝² : IsDomain R
inst✝¹ : Fintype ι
s : ι → M
hs : span R (range s) = ⊤
inst✝ : IsTorsionFree R M
this : ∃ s_1, LinearIndepOn R s s_1 ∧ ∀ i ∉ s_1, ∃ a, a ≠ 0 ∧ a • s i ∈ span R (s '' s_1)
I : Set ι := this.choose
indepI : LinearIndependent (ι := ↑I) R (s ∘ fun x ↦ ↑x)
hI : ∀ i ∉ I, ∃ a, a ≠ 0 ∧ a • s i ∈ span R (s '' I)
N : Submodule R M := span R (range (s ∘ fun x ↦ ↑x))
_sI : ↑I → ↥N := fun i ↦ ⟨s ↑i, ⋯⟩
sI_basis : Basis (↑I) R ↥N := Basis.span indepI
a : ι → R
ha : ∀ (i : ι), a i ≠ 0
ha' : ∀ (i : ι), a i • s i ∈ N
A : R := ∏ i, a i
⊢ A ≠ 0

Tactic:
Finset.prod_ne_zero_iff

Goal state after:
ι : Type u_1
R : Type u_2
inst✝⁶ : CommRing R
M : Type u_3
inst✝⁵ : AddCommGroup M
inst✝⁴ : Module R M
b : ι → M
inst✝³ : IsPrincipalIdealRing R
inst✝² : IsDomain R
inst✝¹ : Fintype ι
s : ι → M
hs : span R (range s) = ⊤
inst✝ : IsTorsionFree R M
this : ∃ s_1, LinearIndepOn R s s_1 ∧ ∀ i ∉ s_1, ∃ a, a ≠ 0 ∧ a • s i ∈ span R (s '' s_1)
I : Set ι := this.choose
indepI : LinearIndependent (ι := ↑I) R (s ∘ fun x ↦ ↑x)
hI : ∀ i ∉ I, ∃ a, a ≠ 0 ∧ a • s i ∈ span R (s '' I)
N : Submodule R M := span R (range (s ∘ fun x ↦ ↑x))
_sI : ↑I → ↥N := fun i ↦ ⟨s ↑i, ⋯⟩
sI_basis : Basis (↑I) R ↥N := Basis.span indepI
a : ι → R
ha : ∀ (i : ι), a i ≠ 0
ha' : ∀ (i : ι), a i • s i ∈ N
A : R := ∏ i, a i
⊢ ∀ a_1 ∈ Finset.univ, a a_1 ≠ 0
Module: Mathlib.RingTheory.Localization.Basic

Goal state before:
pp: case exists_of_eq
R : Type u_1
inst✝⁵ : CommSemiring R
M : Submonoid R
S : Type u_2
inst✝⁴ : CommSemiring S
inst✝³ : Algebra R S
P : Type u_3
inst✝² : CommSemiring P
inst✝¹ : Algebra R P
inst✝ : IsLocalization M S
h : S ≃ₐ[R] P
x y : R
⊢ h.symm.toEquiv ((algebraMap R P) x) = h.symm.toEquiv ((algebraMap R P) y) →
    h.symm ((algebraMap R P) x) = (algebraMap R S) y

Tactic:
←
      h.symm.commutes

Goal state after:
case exists_of_eq
R : Type u_1
inst✝⁵ : CommSemiring R
M : Submonoid R
S : Type u_2
inst✝⁴ : CommSemiring S
inst✝³ : Algebra R S
P : Type u_3
inst✝² : CommSemiring P
inst✝¹ : Algebra R P
inst✝ : IsLocalization M S
h : S ≃ₐ[R] P
x y : R
⊢ h.symm.toEquiv ((algebraMap R P) x) = h.symm.toEquiv ((algebraMap R P) y) →
    h.symm ((algebraMap R P) x) = h.symm ((algebraMap R P) y)
Module: Mathlib.RingTheory.Adjoin.Basic

Goal state before:
pp: R : Type uR
A : Type uA
inst✝² : CommSemiring R
inst✝¹ : CommSemiring A
inst✝ : Algebra R A
s : NonUnitalSubalgebra R A
⊢ Subalgebra.toSubmodule (adjoin R ↑s) = R ∙ 1 ⊔ s.toSubmodule

Tactic:
rw [adjoin_eq_span, Submonoid.closure_eq_one_union, span_union, ← NonUnitalAlgebra.adjoin_eq_span,
      NonUnitalAlgebra.adjoin_eq]

Goal state after:
Module: Mathlib.Algebra.Algebra.Epi

Goal state before:
pp: R : Type u_1
A : Type u_2
inst✝⁴ : CommRing R
inst✝³ : IsDomain R
inst✝² : Field A
inst✝¹ : Algebra R A
inst✝ : IsFractionRing R A
a b : R
f : R →+* A := algebraMap R A
hf : f = algebraMap R A
hb : f b ≠ 0
⊢ 1 ⊗ₜ[R] (f a / f b) = 1 ⊗ₜ[R] (a • (1 / f b))

Tactic:
rw [← smul_div_assoc, algebraMap_eq_smul_one a]

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

Goal state before:
pp: R : Type uR
R' : Type u_1
S : Type uS
T : Type u_2
A : Type uA
B : Type uB
C : Type uC
D : Type uD
E : Type uE
F : Type uF
inst✝⁸ : CommSemiring R
inst✝⁷ : NonUnitalNonAssocSemiring A
inst✝⁶ : Module R A
inst✝⁵ : SMulCommClass R A A
inst✝⁴ : IsScalarTower R A A
inst✝³ : NonUnitalNonAssocSemiring B
inst✝² : Module R B
inst✝¹ : SMulCommClass R B B
inst✝ : IsScalarTower R B B
a b c : A ⊗[R] B
⊢ a * (b + c) = a * b + a * c

Tactic:
by simp [HMul.hMul, Mul.mul]

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

Goal state before:
pp: R : Type uR
R' : Type u_1
S : Type uS
T : Type u_2
A : Type uA
B : Type uB
C : Type uC
D : Type uD
E : Type uE
F : Type uF
inst✝⁸ : CommSemiring R
inst✝⁷ : NonUnitalNonAssocSemiring A
inst✝⁶ : Module R A
inst✝⁵ : SMulCommClass R A A
inst✝⁴ : IsScalarTower R A A
inst✝³ : NonUnitalNonAssocSemiring B
inst✝² : Module R B
inst✝¹ : SMulCommClass R B B
inst✝ : IsScalarTower R B B
a b c : A ⊗[R] B
⊢ (a + b) * c = a * c + b * c

Tactic:
by simp [HMul.hMul, Mul.mul]

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

Goal state before:
pp: R : Type uR
R' : Type u_1
S : Type uS
T : Type u_2
A : Type uA
B : Type uB
C : Type uC
D : Type uD
E : Type uE
F : Type uF
inst✝⁸ : CommSemiring R
inst✝⁷ : NonUnitalNonAssocSemiring A
inst✝⁶ : Module R A
inst✝⁵ : SMulCommClass R A A
inst✝⁴ : IsScalarTower R A A
inst✝³ : NonUnitalNonAssocSemiring B
inst✝² : Module R B
inst✝¹ : SMulCommClass R B B
inst✝ : IsScalarTower R B B
a : A ⊗[R] B
⊢ 0 * a = 0

Tactic:
by simp [HMul.hMul, Mul.mul]

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

Goal state before:
pp: R : Type uR
R' : Type u_1
S : Type uS
T : Type u_2
A : Type uA
B : Type uB
C : Type uC
D : Type uD
E : Type uE
F : Type uF
inst✝⁸ : CommSemiring R
inst✝⁷ : NonUnitalNonAssocSemiring A
inst✝⁶ : Module R A
inst✝⁵ : SMulCommClass R A A
inst✝⁴ : IsScalarTower R A A
inst✝³ : NonUnitalNonAssocSemiring B
inst✝² : Module R B
inst✝¹ : SMulCommClass R B B
inst✝ : IsScalarTower R B B
a : A ⊗[R] B
⊢ a * 0 = 0

Tactic:
by simp [HMul.hMul, Mul.mul]

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

Goal state before:
pp: R : Type uR
R' : Type u_1
S : Type uS
T : Type u_2
A : Type uA
B : Type uB
C : Type uC
D : Type uD
E : Type uE
F : Type uF
inst✝¹² : CommSemiring R
inst✝¹¹ : NonUnitalNonAssocSemiring A
inst✝¹⁰ : Module R A
inst✝⁹ : SMulCommClass R A A
inst✝⁸ : IsScalarTower R A A
inst✝⁷ : NonUnitalNonAssocSemiring B
inst✝⁶ : Module R B
inst✝⁵ : SMulCommClass R B B
inst✝⁴ : IsScalarTower R B B
inst✝³ : Monoid S
inst✝² : DistribMulAction S A
inst✝¹ : SMulCommClass S A A
inst✝ : SMulCommClass R S A
r : S
x y : A ⊗[R] B
⊢ r • x • y = x • r • y

Tactic:
by
    change r • (x * y) = x * r • y
    induction y with
    | zero => simp [smul_zero]
    | tmul a b => induction x with
      | zero => simp [smul_zero]
      | tmul a' b' =>
        dsimp
        rw [TensorProduct.smul_tmul', TensorProduct.smul_tmul', tmul_mul_tmul, mul_smul_comm]
      | add x y hx hy => simp [smul_add, add_mul _, *]
    | add x y hx hy => simp [smul_add, mul_add _, *]

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

Goal state before:
pp: R : Type uR
R' : Type u_1
S : Type uS
T : Type u_2
A : Type uA
B : Type uB
C : Type uC
D : Type uD
E : Type uE
F : Type uF
inst✝⁶ : CommSemiring R
inst✝⁵ : Semiring A
inst✝⁴ : Algebra R A
inst✝³ : Semiring B
inst✝² : Algebra R B
inst✝¹ : Semiring C
inst✝ : Algebra R C
a : A ⊗[R] B
⊢ 0 * a = 0

Tactic:
by simp [HMul.hMul, Mul.mul]

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

Goal state before:
pp: R : Type uR
R' : Type u_1
S : Type uS
T : Type u_2
A : Type uA
B : Type uB
C : Type uC
D : Type uD
E : Type uE
F : Type uF
inst✝⁶ : CommSemiring R
inst✝⁵ : Semiring A
inst✝⁴ : Algebra R A
inst✝³ : Semiring B
inst✝² : Algebra R B
inst✝¹ : Semiring C
inst✝ : Algebra R C
a : A ⊗[R] B
⊢ a * 0 = 0

Tactic:
by simp [HMul.hMul, Mul.mul]

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

Goal state before:
pp: R : Type uR
R' : Type u_1
S : Type uS
T : Type u_2
A : Type uA
B : Type uB
C : Type uC
D : Type uD
E : Type uE
F : Type uF
inst✝⁶ : CommSemiring R
inst✝⁵ : Semiring A
inst✝⁴ : Algebra R A
inst✝³ : Semiring B
inst✝² : Algebra R B
inst✝¹ : Semiring C
inst✝ : Algebra R C
a b c : A ⊗[R] B
⊢ a * (b + c) = a * b + a * c

Tactic:
by simp [HMul.hMul, Mul.mul]

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

Goal state before:
pp: R : Type uR
R' : Type u_1
S : Type uS
T : Type u_2
A : Type uA
B : Type uB
C : Type uC
D : Type uD
E : Type uE
F : Type uF
inst✝⁶ : CommSemiring R
inst✝⁵ : Semiring A
inst✝⁴ : Algebra R A
inst✝³ : Semiring B
inst✝² : Algebra R B
inst✝¹ : Semiring C
inst✝ : Algebra R C
a b c : A ⊗[R] B
⊢ (a + b) * c = a * c + b * c

Tactic:
by simp [HMul.hMul, Mul.mul]

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

Goal state before:
pp: R : Type uR
S : Type uS
inst✝⁶ : CommSemiring R
inst✝⁵ : CommSemiring S
inst✝⁴ : Algebra R S
M : Type u_3
inst✝³ : AddCommMonoid M
inst✝² : Module R M
inst✝¹ : Module S M
inst✝ : IsScalarTower R S M
⊢ Function.Injective ⇑((TensorProduct.mk R S M) 1)

Tactic:
apply Function.RightInverse.injective (g := LinearMap.liftBaseChange S LinearMap.id)

Goal state after:
R : Type uR
S : Type uS
inst✝⁶ : CommSemiring R
inst✝⁵ : CommSemiring S
inst✝⁴ : Algebra R S
M : Type u_3
inst✝³ : AddCommMonoid M
inst✝² : Module R M
inst✝¹ : Module S M
inst✝ : IsScalarTower R S M
⊢ Function.RightInverse ⇑((TensorProduct.mk R S M) 1) ⇑(LinearMap.liftBaseChange S LinearMap.id)
Module: Mathlib.Algebra.Order.Star.Basic

Goal state before:
pp: case mem.mem
R : Type u_1
A : Type u_2
inst✝⁷ : Semiring R
inst✝⁶ : StarRing R
inst✝⁵ : NonUnitalSemiring A
inst✝⁴ : StarRing A
inst✝³ : Module R A
inst✝² : StarModule R A
inst✝¹ : IsScalarTower R A A
inst✝ : SMulCommClass R A A
r✝ : R
a✝ a : A
ha : a ∈ range fun s ↦ star s * s
r : R
⊢ (fun s ↦ star s * s) r • a ∈ AddSubmonoid.closure (range fun s ↦ star s * s)

Tactic:
obtain ⟨a, rfl⟩ := ha

Goal state after:
case mem.mem
R : Type u_1
A : Type u_2
inst✝⁷ : Semiring R
inst✝⁶ : StarRing R
inst✝⁵ : NonUnitalSemiring A
inst✝⁴ : StarRing A
inst✝³ : Module R A
inst✝² : StarModule R A
inst✝¹ : IsScalarTower R A A
inst✝ : SMulCommClass R A A
r✝ : R
a✝ : A
r : R
a : A
⊢ (fun s ↦ star s * s) r • (fun s ↦ star s * s) a ∈ AddSubmonoid.closure (range fun s ↦ star s * s)
Module: Mathlib.RingTheory.TensorProduct.Maps

Goal state before:
pp: R : Type u_1
A : Type u_2
M : Type u_3
N : Type u_4
inst✝⁶ : CommSemiring R
inst✝⁵ : CommSemiring A
inst✝⁴ : Algebra R A
inst✝³ : AddCommMonoid M
inst✝² : Module R M
inst✝¹ : AddCommMonoid N
inst✝ : Module R N
⊢ (tensorProduct R A M M) (1 ⊗ₜ[R] 1) = 1

Tactic:
by
      apply LinearMap.ext
      intro x
      simp only [tensorProduct, TensorProduct.AlgebraTensorModule.lift_apply,
        TensorProduct.lift.tmul, coe_restrictScalars, coe_mk, AddHom.coe_mk, one_smul,
        baseChangeHom_apply, baseChange_eq_ltensor, Module.End.one_eq_id,
        lTensor_id, LinearMap.id_apply]

Goal state after:
Module: Mathlib.Algebra.Order.Star.Basic

Goal state before:
pp: R : Type u_1
A : Type u_2
inst✝¹⁴ : Semiring R
inst✝¹³ : PartialOrder R
inst✝¹² : StarRing R
inst✝¹¹ : StarOrderedRing R
inst✝¹⁰ : NonUnitalSemiring A
inst✝⁹ : StarRing A
inst✝⁸ : PartialOrder A
inst✝⁷ : StarOrderedRing A
inst✝⁶ : Module R A
inst✝⁵ : StarModule R A
inst✝⁴ : IsScalarTower R A A
inst✝³ : SMulCommClass R A A
inst✝² : IsDomain R
inst✝¹ : IsCancelAdd A
inst✝ : Module.IsTorsionFree R A
r : R
hr : r ≠ 0 ∧ r ∈ AddSubmonoid.closure (range fun s ↦ star s * s)
a b : A
hab : a < b
⊢ r • a < r • b

Tactic:
rw [StarOrderedRing.lt_iff] at hab ⊢

Goal state after:
R : Type u_1
A : Type u_2
inst✝¹⁴ : Semiring R
inst✝¹³ : PartialOrder R
inst✝¹² : StarRing R
inst✝¹¹ : StarOrderedRing R
inst✝¹⁰ : NonUnitalSemiring A
inst✝⁹ : StarRing A
inst✝⁸ : PartialOrder A
inst✝⁷ : StarOrderedRing A
inst✝⁶ : Module R A
inst✝⁵ : StarModule R A
inst✝⁴ : IsScalarTower R A A
inst✝³ : SMulCommClass R A A
inst✝² : IsDomain R
inst✝¹ : IsCancelAdd A
inst✝ : Module.IsTorsionFree R A
r : R
hr : r ≠ 0 ∧ r ∈ AddSubmonoid.closure (range fun s ↦ star s * s)
a b : A
hab : ∃ p, p ≠ 0 ∧ p ∈ AddSubmonoid.closure (range fun s ↦ star s * s) ∧ b = a + p
⊢ ∃ p, p ≠ 0 ∧ p ∈ AddSubmonoid.closure (range fun s ↦ star s * s) ∧ r • b = r • a + p
Module: Mathlib.Algebra.Order.Star.Basic

Goal state before:
pp: R : Type u_1
A : Type u_2
inst✝¹⁴ : Semiring R
inst✝¹³ : PartialOrder R
inst✝¹² : StarRing R
inst✝¹¹ : StarOrderedRing R
inst✝¹⁰ : NonUnitalSemiring A
inst✝⁹ : StarRing A
inst✝⁸ : PartialOrder A
inst✝⁷ : StarOrderedRing A
inst✝⁶ : Module R A
inst✝⁵ : StarModule R A
inst✝⁴ : IsScalarTower R A A
inst✝³ : SMulCommClass R A A
inst✝² : IsDomain R
inst✝¹ : IsCancelAdd A
inst✝ : Module.IsTorsionFree R A
r : R
hr : r ≠ 0 ∧ r ∈ AddSubmonoid.closure (range fun s ↦ star s * s)
a✝ a : A
ha₀ : a ≠ 0
ha : a ∈ AddSubmonoid.closure (range fun s ↦ star s * s)
⊢ ∃ p, p ≠ 0 ∧ p ∈ AddSubmonoid.closure (range fun s ↦ star s * s) ∧ r • (a✝ + a) = r • a✝ + p

Tactic:
obtain ⟨hr₀, hr⟩ := hr

Goal state after:
R : Type u_1
A : Type u_2
inst✝¹⁴ : Semiring R
inst✝¹³ : PartialOrder R
inst✝¹² : StarRing R
inst✝¹¹ : StarOrderedRing R
inst✝¹⁰ : NonUnitalSemiring A
inst✝⁹ : StarRing A
inst✝⁸ : PartialOrder A
inst✝⁷ : StarOrderedRing A
inst✝⁶ : Module R A
inst✝⁵ : StarModule R A
inst✝⁴ : IsScalarTower R A A
inst✝³ : SMulCommClass R A A
inst✝² : IsDomain R
inst✝¹ : IsCancelAdd A
inst✝ : Module.IsTorsionFree R A
r : R
a✝ a : A
ha₀ : a ≠ 0
ha : a ∈ AddSubmonoid.closure (range fun s ↦ star s * s)
hr₀ : r ≠ 0
hr : r ∈ AddSubmonoid.closure (range fun s ↦ star s * s)
⊢ ∃ p, p ≠ 0 ∧ p ∈ AddSubmonoid.closure (range fun s ↦ star s * s) ∧ r • (a✝ + a) = r • a✝ + p
Module: Mathlib.LinearAlgebra.Dimension.Finite

Goal state before:
pp: case inr
R : Type u
M : Type v
inst✝² : Semiring R
inst✝¹ : AddCommMonoid M
inst✝ : Module R M
n : ℕ
hn : ↑n ≤ Module.rank R M
h : ↑n < Module.rank R M
⊢ ∃ s, s.card = n ∧ LinearIndepOn R id ↑s

Tactic:
obtain ⟨s, hs, hs'⟩ := exists_set_linearIndependent_of_lt_rank h
    have : Finite s := lt_aleph0_iff_finite.mp (hs ▸ natCast_lt_aleph0)
    cases nonempty_fintype s
    exact ⟨s.toFinset, by simpa using hs, by simpa⟩

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

Goal state before:
pp: R : Type u_1
M : Type u_2
inst✝⁴ : Ring R
inst✝³ : AddCommGroup M
inst✝² : Module R M
inst✝¹ : Module.Finite R M
inst✝ : StrongRankCondition R
t : Finset M
h : finrank R M + 1 < #t
x₀ : M
x₀_mem : x₀ ∈ t
shift : M ↪ M := { toFun := fun x ↦ x - x₀, inj' := ⋯ }
t' : Finset M := Finset.map shift (t.erase x₀)
⊢ ∃ f, ∑ e ∈ t, f e • e = 0 ∧ ∑ e ∈ t, f e = 0 ∧ ∃ x ∈ t, f x ≠ 0

Tactic:
have h' : finrank R M < t'.card := by
    rw [card_map, card_erase_of_mem x₀_mem]
    exact Nat.lt_pred_iff.mpr h

Goal state after:
R : Type u_1
M : Type u_2
inst✝⁴ : Ring R
inst✝³ : AddCommGroup M
inst✝² : Module R M
inst✝¹ : Module.Finite R M
inst✝ : StrongRankCondition R
t : Finset M
h : finrank R M + 1 < #t
x₀ : M
x₀_mem : x₀ ∈ t
shift : M ↪ M := { toFun := fun x ↦ x - x₀, inj' := ⋯ }
t' : Finset M := Finset.map shift (t.erase x₀)
h' : finrank R M < #t'
⊢ ∃ f, ∑ e ∈ t, f e • e = 0 ∧ ∑ e ∈ t, f e = 0 ∧ ∃ x ∈ t, f x ≠ 0
Module: Mathlib.LinearAlgebra.Basis.VectorSpace

Goal state before:
pp: K : Type u_6
V : Type u_7
inst✝² : Field K
inst✝¹ : AddCommGroup V
inst✝ : Module K V
f : V →ₗ[K] K
v : V
hfv : f v ≠ 0
b₁ : Basis (↑(Basis.ofVectorSpaceIndex K ↥f.ker)) K ↥f.ker := Basis.ofVectorSpace K ↥f.ker
s : Set V := ⇑f.ker.subtype '' Set.range ⇑b₁
hs : span K s = f.ker
n : Set V := insert v s
H₁ : LinearIndepOn K _root_.id n
H₂ : ⊤ ≤ span K n
⊢ ∃ n b i, v = b i ∧ f = f v • b.coord i

Tactic:
set b := Basis.mk H₁ (by simpa using H₂)

Goal state after:
K : Type u_6
V : Type u_7
inst✝² : Field K
inst✝¹ : AddCommGroup V
inst✝ : Module K V
f : V →ₗ[K] K
v : V
hfv : f v ≠ 0
b₁ : Basis (↑(Basis.ofVectorSpaceIndex K ↥f.ker)) K ↥f.ker := Basis.ofVectorSpace K ↥f.ker
s : Set V := ⇑f.ker.subtype '' Set.range ⇑b₁
hs : span K s = f.ker
n : Set V := insert v s
H₁ : LinearIndepOn K _root_.id n
H₂ : ⊤ ≤ span K n
b : Basis (↑n) K V := Basis.mk H₁ ⋯
⊢ ∃ n b i, v = b i ∧ f = f v • b.coord i
Module: Mathlib.LinearAlgebra.Dimension.Finite

Goal state before:
pp: R : Type u_1
M : Type u_2
inst✝⁴ : Ring R
inst✝³ : AddCommGroup M
inst✝² : Module R M
inst✝¹ : Module.Finite R M
inst✝ : StrongRankCondition R
t : Finset M
h : finrank R M + 1 < #t
⊢ ∃ f, ∑ e ∈ t, f e • e = 0 ∧ ∑ e ∈ t, f e = 0 ∧ ∃ x ∈ t, f x ≠ 0

Tactic:
obtain ⟨x₀, x₀_mem⟩ := card_pos.1 ((Nat.succ_pos _).trans h)
  -- and apply the previous lemma to the {xᵢ - x₀}
  let shift : M ↪ M := ⟨(· - x₀), sub_left_injective⟩
  classical
  let t' := (t.erase x₀).map shift
  have h' : finrank R M < t'.card := by
    rw [card_map, card_erase_of_mem x₀_mem]
    exact Nat.lt_pred_iff.mpr h
  -- to obtain a function `g`.
  obtain ⟨g, gsum, x₁, x₁_mem, nz⟩ := exists_nontrivial_relation_of_finrank_lt_card h'
  -- Then obtain `f` by translating back by `x₀`,
  -- and setting the value of `f` at `x₀` to ensure `∑ e ∈ t, f e = 0`.
  let f : M → R := fun z ↦ if z = x₀ then -∑ z ∈ t.erase x₀, g (z - x₀) else g (z - x₀)
  refine ⟨f, ?_, ?_, ?_⟩
  -- After this, it's a matter of verifying the properties,
  -- based on the corresponding properties for `g`.
  · rw [sum_map, Embedding.coeFn_mk] at gsum
    simp_rw [f, ← t.sum_erase_add _ x₀_mem, if_pos, neg_smul, sum_smul,
             ← sub_eq_add_neg, ← sum_sub_distrib, ← gsum, smul_sub]
    refine sum_congr rfl fun x x_mem ↦ ?_
    rw [if_neg (mem_erase.mp x_mem).1]
  · simp_rw [f, ← t.sum_erase_add _ x₀_mem, if_pos, add_neg_eq_zero]
    exact sum_congr rfl fun x x_mem ↦ if_neg (mem_erase.mp x_mem).1
  · obtain ⟨x₁, x₁_mem', rfl⟩ := Finset.mem_map.mp x₁_mem
    have := mem_erase.mp x₁_mem'
    exact ⟨x₁, by
      simpa only [f, Embedding.coeFn_mk, sub_add_cancel, this.2, true_and, if_neg this.1]⟩

Goal state after: