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eq_mul_of_inv_mul_eq (h : b⁻¹ * a = c) : a = b * c
by simp [h.symm, mul_inv_cancel_left]
lemma
eq_mul_of_inv_mul_eq
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "mul_inv_cancel_left" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_eq_of_eq_inv_mul (h : b = a⁻¹ * c) : a * b = c
by rw [h, mul_inv_cancel_left]
lemma
mul_eq_of_eq_inv_mul
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "mul_inv_cancel_left" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_eq_of_eq_mul_inv (h : a = c * b⁻¹) : a * b = c
by simp [h]
lemma
mul_eq_of_eq_mul_inv
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_eq_one_iff_eq_inv : a * b = 1 ↔ a = b⁻¹
⟨eq_inv_of_mul_eq_one_left, λ h, by rw [h, mul_left_inv]⟩
theorem
mul_eq_one_iff_eq_inv
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "mul_left_inv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_eq_one_iff_inv_eq : a * b = 1 ↔ a⁻¹ = b
by rw [mul_eq_one_iff_eq_inv, inv_eq_iff_eq_inv]
theorem
mul_eq_one_iff_inv_eq
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "inv_eq_iff_eq_inv", "mul_eq_one_iff_eq_inv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_inv_iff_mul_eq_one : a = b⁻¹ ↔ a * b = 1
mul_eq_one_iff_eq_inv.symm
theorem
eq_inv_iff_mul_eq_one
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv_eq_iff_mul_eq_one : a⁻¹ = b ↔ a * b = 1
mul_eq_one_iff_inv_eq.symm
theorem
inv_eq_iff_mul_eq_one
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_mul_inv_iff_mul_eq : a = b * c⁻¹ ↔ a * c = b
⟨λ h, by rw [h, inv_mul_cancel_right], λ h, by rw [← h, mul_inv_cancel_right]⟩
theorem
eq_mul_inv_iff_mul_eq
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "inv_mul_cancel_right", "mul_inv_cancel_right" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_inv_mul_iff_mul_eq : a = b⁻¹ * c ↔ b * a = c
⟨λ h, by rw [h, mul_inv_cancel_left], λ h, by rw [← h, inv_mul_cancel_left]⟩
theorem
eq_inv_mul_iff_mul_eq
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "inv_mul_cancel_left", "mul_inv_cancel_left" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv_mul_eq_iff_eq_mul : a⁻¹ * b = c ↔ b = a * c
⟨λ h, by rw [← h, mul_inv_cancel_left], λ h, by rw [h, inv_mul_cancel_left]⟩
theorem
inv_mul_eq_iff_eq_mul
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "inv_mul_cancel_left", "mul_inv_cancel_left" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_inv_eq_iff_eq_mul : a * b⁻¹ = c ↔ a = c * b
⟨λ h, by rw [← h, inv_mul_cancel_right], λ h, by rw [h, mul_inv_cancel_right]⟩
theorem
mul_inv_eq_iff_eq_mul
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "inv_mul_cancel_right", "mul_inv_cancel_right" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_inv_eq_one : a * b⁻¹ = 1 ↔ a = b
by rw [mul_eq_one_iff_eq_inv, inv_inv]
theorem
mul_inv_eq_one
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "inv_inv", "mul_eq_one_iff_eq_inv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv_mul_eq_one : a⁻¹ * b = 1 ↔ a = b
by rw [mul_eq_one_iff_eq_inv, inv_inj]
theorem
inv_mul_eq_one
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "inv_inj", "mul_eq_one_iff_eq_inv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_left_injective : function.injective (λ a, a / b)
by simpa only [div_eq_mul_inv] using λ a a' h, mul_left_injective (b⁻¹) h
lemma
div_left_injective
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_eq_mul_inv", "mul_left_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_right_injective : function.injective (λ a, b / a)
by simpa only [div_eq_mul_inv] using λ a a' h, inv_injective (mul_right_injective b h)
lemma
div_right_injective
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_eq_mul_inv", "inv_injective", "mul_right_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_mul_cancel' (a b : G) : a / b * b = a
by rw [div_eq_mul_inv, inv_mul_cancel_right a b]
lemma
div_mul_cancel'
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_eq_mul_inv", "inv_mul_cancel_right" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_self' (a : G) : a / a = 1
by rw [div_eq_mul_inv, mul_right_inv a]
lemma
div_self'
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_eq_mul_inv", "mul_right_inv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_div_cancel'' (a b : G) : a * b / b = a
by rw [div_eq_mul_inv, mul_inv_cancel_right a b]
lemma
mul_div_cancel''
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_eq_mul_inv", "mul_inv_cancel_right" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_mul_cancel''' (a b : G) : a / (b * a) = b⁻¹
by rw [←inv_div, mul_div_cancel'']
lemma
div_mul_cancel'''
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "mul_div_cancel''" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_div_mul_right_eq_div (a b c : G) : (a * c) / (b * c) = a / b
by rw [div_mul_eq_div_div_swap]; simp only [mul_left_inj, eq_self_iff_true, mul_div_cancel'']
lemma
mul_div_mul_right_eq_div
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_mul_eq_div_div_swap", "mul_div_cancel''", "mul_left_inj" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_div_of_mul_eq' (h : a * c = b) : a = b / c
by simp [← h]
lemma
eq_div_of_mul_eq'
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_eq_of_eq_mul'' (h : a = c * b) : a / b = c
by simp [h]
lemma
div_eq_of_eq_mul''
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_mul_of_div_eq (h : a / c = b) : a = b * c
by simp [← h]
lemma
eq_mul_of_div_eq
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_eq_of_eq_div (h : a = c / b) : a * b = c
by simp [h]
lemma
mul_eq_of_eq_div
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_right_inj : a / b = a / c ↔ b = c
div_right_injective.eq_iff
lemma
div_right_inj
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_left_inj : b / a = c / a ↔ b = c
by { rw [div_eq_mul_inv, div_eq_mul_inv], exact mul_left_inj _ }
lemma
div_left_inj
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_eq_mul_inv", "mul_left_inj" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_mul_div_cancel' (a b c : G) : (a / b) * (b / c) = a / c
by rw [← mul_div_assoc, div_mul_cancel']
lemma
div_mul_div_cancel'
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_mul_cancel'", "mul_div_assoc" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_div_div_cancel_right' (a b c : G) : (a / c) / (b / c) = a / b
by rw [← inv_div c b, div_inv_eq_mul, div_mul_div_cancel']
lemma
div_div_div_cancel_right'
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_inv_eq_mul", "div_mul_div_cancel'", "inv_div" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_eq_one : a / b = 1 ↔ a = b
⟨eq_of_div_eq_one, λ h, by rw [h, div_self']⟩
theorem
div_eq_one
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_self'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_ne_one : a / b ≠ 1 ↔ a ≠ b
not_congr div_eq_one
theorem
div_ne_one
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_eq_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_eq_self : a / b = a ↔ b = 1
by rw [div_eq_mul_inv, mul_right_eq_self, inv_eq_one]
theorem
div_eq_self
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_eq_mul_inv", "inv_eq_one", "mul_right_eq_self" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_div_iff_mul_eq' : a = b / c ↔ a * c = b
by rw [div_eq_mul_inv, eq_mul_inv_iff_mul_eq]
theorem
eq_div_iff_mul_eq'
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_eq_mul_inv", "eq_mul_inv_iff_mul_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_eq_iff_eq_mul : a / b = c ↔ a = c * b
by rw [div_eq_mul_inv, mul_inv_eq_iff_eq_mul]
theorem
div_eq_iff_eq_mul
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_eq_mul_inv", "mul_inv_eq_iff_eq_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_iff_eq_of_div_eq_div (H : a / b = c / d) : a = b ↔ c = d
by rw [← div_eq_one, H, div_eq_one]
theorem
eq_iff_eq_of_div_eq_div
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_eq_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
left_inverse_div_mul_left (c : G) : function.left_inverse (λ x, x / c) (λ x, x * c)
assume x, mul_div_cancel'' x c
theorem
left_inverse_div_mul_left
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "mul_div_cancel''" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
left_inverse_mul_left_div (c : G) : function.left_inverse (λ x, x * c) (λ x, x / c)
assume x, div_mul_cancel' x c
theorem
left_inverse_mul_left_div
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_mul_cancel'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
left_inverse_mul_right_inv_mul (c : G) : function.left_inverse (λ x, c * x) (λ x, c⁻¹ * x)
assume x, mul_inv_cancel_left c x
theorem
left_inverse_mul_right_inv_mul
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "mul_inv_cancel_left" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
left_inverse_inv_mul_mul_right (c : G) : function.left_inverse (λ x, c⁻¹ * x) (λ x, c * x)
assume x, inv_mul_cancel_left c x
theorem
left_inverse_inv_mul_mul_right
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "inv_mul_cancel_left" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_npow_eq_one_of_zpow_eq_one {n : ℤ} (hn : n ≠ 0) {x : G} (h : x ^ n = 1) : ∃ n : ℕ, 0 < n ∧ x ^ n = 1
begin cases n with n n, { rw zpow_of_nat at h, refine ⟨n, nat.pos_of_ne_zero (λ n0, hn _), h⟩, rw n0, refl }, { rw [zpow_neg_succ_of_nat, inv_eq_one] at h, refine ⟨n + 1, n.succ_pos, h⟩ } end
lemma
exists_npow_eq_one_of_zpow_eq_one
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "inv_eq_one", "zpow_neg_succ_of_nat", "zpow_of_nat" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_eq_of_eq_mul' {a b c : G} (h : a = b * c) : a / b = c
by rw [h, div_eq_mul_inv, mul_comm, inv_mul_cancel_left]
lemma
div_eq_of_eq_mul'
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_eq_mul_inv", "inv_mul_cancel_left", "mul_comm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_div_mul_left_eq_div (a b c : G) : (c * a) / (c * b) = a / b
by simp
lemma
mul_div_mul_left_eq_div
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_div_of_mul_eq'' (h : c * a = b) : a = b / c
by simp [h.symm]
lemma
eq_div_of_mul_eq''
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_mul_of_div_eq' (h : a / b = c) : a = b * c
by simp [h.symm]
lemma
eq_mul_of_div_eq'
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_eq_of_eq_div' (h : b = c / a) : a * b = c
begin simp [h], rw [mul_comm c, mul_inv_cancel_left] end
lemma
mul_eq_of_eq_div'
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "mul_comm", "mul_inv_cancel_left" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_div_self' (a b : G) : a / (a / b) = b
by simpa using mul_inv_cancel_left a b
lemma
div_div_self'
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "mul_inv_cancel_left" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_eq_div_mul_div (a b c : G) : a / b = c / b * (a / c)
by simp [mul_left_comm c]
lemma
div_eq_div_mul_div
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "mul_left_comm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_div_cancel (a b : G) : a / (a / b) = b
div_div_self' a b
lemma
div_div_cancel
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_div_self'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_div_cancel_left (a b : G) : a / b / a = b⁻¹
by simp
lemma
div_div_cancel_left
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_div_iff_mul_eq'' : a = b / c ↔ c * a = b
by rw [eq_div_iff_mul_eq', mul_comm]
lemma
eq_div_iff_mul_eq''
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "eq_div_iff_mul_eq'", "mul_comm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_eq_iff_eq_mul' : a / b = c ↔ a = b * c
by rw [div_eq_iff_eq_mul, mul_comm]
lemma
div_eq_iff_eq_mul'
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_eq_iff_eq_mul", "mul_comm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_div_cancel''' (a b : G) : a * b / a = b
by rw [div_eq_inv_mul, inv_mul_cancel_left]
lemma
mul_div_cancel'''
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_eq_inv_mul", "inv_mul_cancel_left" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_div_cancel'_right (a b : G) : a * (b / a) = b
by rw [← mul_div_assoc, mul_div_cancel''']
lemma
mul_div_cancel'_right
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "mul_div_assoc", "mul_div_cancel'''" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_mul_cancel'' (a b : G) : a / (a * b) = b⁻¹
by rw [← inv_div, mul_div_cancel''']
lemma
div_mul_cancel''
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "inv_div", "mul_div_cancel'''" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_mul_inv_cancel'_right (a b : G) : a * (b * a⁻¹) = b
by rw [← div_eq_mul_inv, mul_div_cancel'_right a b]
lemma
mul_mul_inv_cancel'_right
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_eq_mul_inv", "mul_div_cancel'_right" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_mul_div_cancel (a b c : G) : (a * c) * (b / c) = a * b
by rw [mul_assoc, mul_div_cancel'_right]
lemma
mul_mul_div_cancel
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "mul_assoc", "mul_div_cancel'_right" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_mul_mul_cancel (a b c : G) : (a / c) * (b * c) = a * b
by rw [mul_left_comm, div_mul_cancel', mul_comm]
lemma
div_mul_mul_cancel
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_mul_cancel'", "mul_comm", "mul_left_comm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_mul_div_cancel'' (a b c : G) : (a / b) * (c / a) = c / b
by rw mul_comm; apply div_mul_div_cancel'
lemma
div_mul_div_cancel''
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_mul_div_cancel'", "mul_comm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_div_div_cancel (a b c : G) : (a * b) / (a / c) = b * c
by rw [← div_mul, mul_div_cancel''']
lemma
mul_div_div_cancel
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_mul", "mul_div_cancel'''" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_div_div_cancel_left (a b c : G) : (c / a) / (c / b) = b / a
by rw [← inv_div b c, div_inv_eq_mul, mul_comm, div_mul_div_cancel']
lemma
div_div_div_cancel_left
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_inv_eq_mul", "div_mul_div_cancel'", "inv_div", "mul_comm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_eq_div_iff_mul_eq_mul : a / b = c / d ↔ a * d = c * b
begin rw [div_eq_iff_eq_mul, div_mul_eq_mul_div, eq_comm, div_eq_iff_eq_mul'], simp only [mul_comm, eq_comm] end
lemma
div_eq_div_iff_mul_eq_mul
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_eq_iff_eq_mul", "div_eq_iff_eq_mul'", "div_mul_eq_mul_div", "mul_comm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
div_eq_div_iff_div_eq_div : a / b = c / d ↔ a / c = b / d
by rw [div_eq_iff_eq_mul, div_mul_eq_mul_div, div_eq_iff_eq_mul', mul_div_assoc]
lemma
div_eq_div_iff_div_eq_div
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "div_eq_iff_eq_mul", "div_eq_iff_eq_mul'", "div_mul_eq_mul_div", "mul_div_assoc" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bit0_sub (a b : M) : bit0 (a - b) = bit0 a - bit0 b
sub_add_sub_comm _ _ _ _
lemma
bit0_sub
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bit1_sub [has_one M] (a b : M) : bit1 (a - b) = bit1 a - bit0 b
(congr_arg (+ (1 : M)) $ bit0_sub a b : _).trans $ sub_add_eq_add_sub _ _ _
lemma
bit1_sub
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "bit0_sub" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
multiplicative_of_symmetric_of_is_total (hsymm : symmetric p) (hf_swap : ∀ {a b}, p a b → f a b * f b a = 1) (hmul : ∀ {a b c}, r a b → r b c → p a b → p b c → p a c → f a c = f a b * f b c) {a b c : α} (pab : p a b) (pbc : p b c) (pac : p a c) : f a c = f a b * f b c
begin suffices : ∀ {b c}, r b c → p a b → p b c → p a c → f a c = f a b * f b c, { obtain rbc | rcb := total_of r b c, { exact this rbc pab pbc pac }, { rw [this rcb pac (hsymm pbc) pab, mul_assoc, hf_swap (hsymm pbc), mul_one] } }, intros b c rbc pab pbc pac, obtain rab | rba := total_of r a b, { exa...
lemma
multiplicative_of_symmetric_of_is_total
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "mul_assoc", "mul_one", "one_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
multiplicative_of_is_total (p : α → Prop) (hswap : ∀ {a b}, p a → p b → f a b * f b a = 1) (hmul : ∀ {a b c}, r a b → r b c → p a → p b → p c → f a c = f a b * f b c) {a b c : α} (pa : p a) (pb : p b) (pc : p c) : f a c = f a b * f b c
begin apply multiplicative_of_symmetric_of_is_total (λ a b, p a ∧ p b) r f (λ _ _, and.swap), { simp_rw and_imp, exact @hswap }, { exact λ a b c rab rbc pab pbc pac, hmul rab rbc pab.1 pab.2 pac.2 }, exacts [⟨pa, pb⟩, ⟨pb, pc⟩, ⟨pa, pc⟩], end
lemma
multiplicative_of_is_total
algebra.group
src/algebra/group/basic.lean
[ "algebra.group.defs" ]
[ "and_imp", "multiplicative_of_symmetric_of_is_total" ]
If a binary function from a type equipped with a total relation `r` to a monoid is anti-symmetric (i.e. satisfies `f a b * f b a = 1`), in order to show it is multiplicative (i.e. satisfies `f a c = f a b * f b c`), we may assume `r a b` and `r b c` are satisfied. We allow restricting to a subset specified by a p...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
commutator_element {G : Type*} [group G] : has_bracket G G
⟨λ g₁ g₂, g₁ * g₂ * g₁⁻¹ * g₂⁻¹⟩
instance
commutator_element
algebra.group
src/algebra/group/commutator.lean
[ "algebra.group.defs", "data.bracket" ]
[ "group", "has_bracket" ]
The commutator of two elements `g₁` and `g₂`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
commutator_element_def {G : Type*} [group G] (g₁ g₂ : G) : ⁅g₁, g₂⁆ = g₁ * g₂ * g₁⁻¹ * g₂⁻¹
rfl
lemma
commutator_element_def
algebra.group
src/algebra/group/commutator.lean
[ "algebra.group.defs", "data.bracket" ]
[ "group" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
commute {S : Type*} [has_mul S] (a b : S) : Prop
semiconj_by a b b
def
commute
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "semiconj_by" ]
Two elements commute if `a * b = b * a`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq {a b : S} (h : commute a b) : a * b = b * a
h
lemma
commute.eq
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute" ]
Equality behind `commute a b`; useful for rewriting.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
refl (a : S) : commute a a
eq.refl (a * a)
lemma
commute.refl
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute" ]
Any element commutes with itself.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
symm {a b : S} (h : commute a b) : commute b a
eq.symm h
lemma
commute.symm
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute" ]
If `a` commutes with `b`, then `b` commutes with `a`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
semiconj_by {a b : S} (h : commute a b) : semiconj_by a b b
h
theorem
commute.semiconj_by
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute", "semiconj_by" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
symm_iff {a b : S} : commute a b ↔ commute b a
⟨commute.symm, commute.symm⟩
theorem
commute.symm_iff
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
on_is_refl {f : G → S} : is_refl G (λ a b, commute (f a) (f b))
⟨λ _, commute.refl _⟩
instance
commute.on_is_refl
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute", "commute.refl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_right (hab : commute a b) (hac : commute a c) : commute a (b * c)
hab.mul_right hac
lemma
commute.mul_right
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute" ]
If `a` commutes with both `b` and `c`, then it commutes with their product.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_left (hac : commute a c) (hbc : commute b c) : commute (a * b) c
hac.mul_left hbc
lemma
commute.mul_left
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute" ]
If both `a` and `b` commute with `c`, then their product commutes with `c`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
right_comm (h : commute b c) (a : S) : a * b * c = a * c * b
by simp only [mul_assoc, h.eq]
lemma
commute.right_comm
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute", "mul_assoc" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
left_comm (h : commute a b) (c) : a * (b * c) = b * (a * c)
by simp only [← mul_assoc, h.eq]
lemma
commute.left_comm
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute", "mul_assoc" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_mul_mul_comm (hbc : commute b c) (a d : S) : (a * b) * (c * d) = (a * c) * (b * d)
by simp only [hbc.left_comm, mul_assoc]
lemma
commute.mul_mul_mul_comm
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute", "mul_assoc", "mul_mul_mul_comm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
all {S : Type*} [comm_semigroup S] (a b : S) : commute a b
mul_comm a b
theorem
commute.all
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "comm_semigroup", "commute", "mul_comm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
one_right (a : M) : commute a 1
semiconj_by.one_right a
theorem
commute.one_right
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute", "semiconj_by.one_right" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
one_left (a : M) : commute 1 a
semiconj_by.one_left a
theorem
commute.one_left
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute", "semiconj_by.one_left" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pow_right (h : commute a b) (n : ℕ) : commute a (b ^ n)
h.pow_right n
theorem
commute.pow_right
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pow_left (h : commute a b) (n : ℕ) : commute (a ^ n) b
(h.symm.pow_right n).symm
theorem
commute.pow_left
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pow_pow (h : commute a b) (m n : ℕ) : commute (a ^ m) (b ^ n)
(h.pow_left m).pow_right n
theorem
commute.pow_pow
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
self_pow (a : M) (n : ℕ) : commute a (a ^ n)
(commute.refl a).pow_right n
theorem
commute.self_pow
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute", "commute.refl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pow_self (a : M) (n : ℕ) : commute (a ^ n) a
(commute.refl a).pow_left n
theorem
commute.pow_self
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute", "commute.refl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pow_pow_self (a : M) (m n : ℕ) : commute (a ^ m) (a ^ n)
(commute.refl a).pow_pow m n
theorem
commute.pow_pow_self
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute", "commute.refl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.pow_succ' (a : M) (n : ℕ) : a ^ (n + 1) = a ^ n * a
(pow_succ a n).trans (self_pow _ _)
theorem
pow_succ'
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "pow_succ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
units_inv_right : commute a u → commute a ↑u⁻¹
semiconj_by.units_inv_right
theorem
commute.units_inv_right
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute", "semiconj_by.units_inv_right" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
units_inv_right_iff : commute a ↑u⁻¹ ↔ commute a u
semiconj_by.units_inv_right_iff
theorem
commute.units_inv_right_iff
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute", "semiconj_by.units_inv_right_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
units_inv_left : commute ↑u a → commute ↑u⁻¹ a
semiconj_by.units_inv_symm_left
theorem
commute.units_inv_left
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute", "semiconj_by.units_inv_symm_left" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
units_inv_left_iff: commute ↑u⁻¹ a ↔ commute ↑u a
semiconj_by.units_inv_symm_left_iff
theorem
commute.units_inv_left_iff
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute", "semiconj_by.units_inv_symm_left_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
units_coe : commute u₁ u₂ → commute (u₁ : M) u₂
semiconj_by.units_coe
theorem
commute.units_coe
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute", "semiconj_by.units_coe" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
units_of_coe : commute (u₁ : M) u₂ → commute u₁ u₂
semiconj_by.units_of_coe
theorem
commute.units_of_coe
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute", "semiconj_by.units_of_coe" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
units_coe_iff : commute (u₁ : M) u₂ ↔ commute u₁ u₂
semiconj_by.units_coe_iff
theorem
commute.units_coe_iff
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute", "semiconj_by.units_coe_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.units.left_of_mul (u : Mˣ) (a b : M) (hu : a * b = u) (hc : commute a b) : Mˣ
{ val := a, inv := b * ↑u⁻¹, val_inv := by rw [← mul_assoc, hu, u.mul_inv], inv_val := have commute a u, from hu ▸ (commute.refl _).mul_right hc, by rw [← this.units_inv_right.right_comm, ← hc.eq, hu, u.mul_inv] }
def
units.left_of_mul
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute", "commute.refl", "mul_assoc" ]
If the product of two commuting elements is a unit, then the left multiplier is a unit.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.units.right_of_mul (u : Mˣ) (a b : M) (hu : a * b = u) (hc : commute a b) : Mˣ
u.left_of_mul b a (hc.eq ▸ hu) hc.symm
def
units.right_of_mul
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute" ]
If the product of two commuting elements is a unit, then the right multiplier is a unit.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_unit_mul_iff (h : commute a b) : is_unit (a * b) ↔ is_unit a ∧ is_unit b
⟨λ ⟨u, hu⟩, ⟨(u.left_of_mul a b hu.symm h).is_unit, (u.right_of_mul a b hu.symm h).is_unit⟩, λ H, H.1.mul H.2⟩
lemma
commute.is_unit_mul_iff
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute", "is_unit" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.is_unit_mul_self_iff : is_unit (a * a) ↔ is_unit a
(commute.refl a).is_unit_mul_iff.trans (and_self _)
lemma
is_unit_mul_self_iff
algebra.group
src/algebra/group/commute.lean
[ "algebra.group.semiconj" ]
[ "commute.refl", "is_unit" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83