Documentation

Mathlib.Algebra.Ring.NonZeroDivisors

Non-zero divisors in a ring #

theorem IsLeftRegular.pow_injective {R : Type u_1} [Monoid R] {r : R} [IsMulTorsionFree R] (hx : IsLeftRegular r) (hx' : r ≠ 1) :
Function.Injective fun (n : ℕ) => r ^ n
theorem IsAddLeftRegular.nsmul_injective {R : Type u_1} [AddMonoid R] {r : R} [IsAddTorsionFree R] (hx : IsAddLeftRegular r) (hx' : r ≠ 0) :
Function.Injective fun (n : ℕ) => n • r
theorem IsRightRegular.pow_injective {M : Type u_2} [Monoid M] [IsMulTorsionFree M] {x : M} (hx : IsRightRegular x) (hx' : x ≠ 1) :
Function.Injective fun (n : ℕ) => x ^ n
theorem IsAddRightRegular.nsmul_injective {M : Type u_2} [AddMonoid M] [IsAddTorsionFree M] {x : M} (hx : IsAddRightRegular x) (hx' : x ≠ 0) :
Function.Injective fun (n : ℕ) => n • x
theorem IsMulTorsionFree.pow_right_injective {M : Type u_2} [CancelMonoid M] [IsMulTorsionFree M] {x : M} (hx : x ≠ 1) :
Function.Injective fun (n : ℕ) => x ^ n
@[simp]
theorem IsMulTorsionFree.pow_right_inj {M : Type u_2} [CancelMonoid M] [IsMulTorsionFree M] {x : M} (hx : x ≠ 1) {n m : ℕ} :
x ^ n = x ^ m ↔ n = m
theorem IsMulTorsionFree.pow_right_injective₀ {M : Type u_2} [MonoidWithZero M] [IsLeftCancelMulZero M] [IsMulTorsionFree M] {x : M} (hx : x ≠ 1) (hx' : x ≠ 0) :
Function.Injective fun (n : ℕ) => x ^ n
@[simp]
theorem IsMulTorsionFree.pow_right_inj₀ {M : Type u_2} [MonoidWithZero M] [IsLeftCancelMulZero M] [IsMulTorsionFree M] {x : M} (hx : x ≠ 1) (hx' : x ≠ 0) {n m : ℕ} :
x ^ n = x ^ m ↔ n = m
theorem IsLeftRegular.isUnit_of_finite {R : Type u_1} [Monoid R] {r : R} [Finite R] (h : IsLeftRegular r) :
theorem IsRightRegular.isUnit_of_finite {R : Type u_1} [Monoid R] {r : R} [Finite R] (h : IsRightRegular r) :
theorem le_nonZeroDivisors_iff_isRegular {R : Type u_1} [Ring R] {S : Submonoid R} :
S ≤ nonZeroDivisors R ↔ ∀ (s : ↥S), IsRegular ↑s
theorem mul_cancel_left_mem_nonZeroDivisorsLeft {R : Type u_1} [Ring R] {x y r : R} (hr : r ∈ nonZeroDivisorsLeft R) :
r * x = r * y ↔ x = y
theorem mul_cancel_right_mem_nonZeroDivisorsRight {R : Type u_1} [Ring R] {x y r : R} (hr : r ∈ nonZeroDivisorsRight R) :
x * r = y * r ↔ x = y
@[simp]
theorem mul_cancel_left_mem_nonZeroDivisors {R : Type u_1} [Ring R] {x y r : R} (hr : r ∈ nonZeroDivisors R) :
r * x = r * y ↔ x = y
theorem mul_cancel_left_coe_nonZeroDivisors {R : Type u_1} [Ring R] {x y : R} {c : ↥(nonZeroDivisors R)} :
↑c * x = ↑c * y ↔ x = y
theorem mul_cancel_right_mem_nonZeroDivisors {R : Type u_1} [Ring R] {x y r : R} (hr : r ∈ nonZeroDivisors R) :
x * r = y * r ↔ x = y
theorem mul_cancel_right_coe_nonZeroDivisors {R : Type u_1} [Ring R] {x y : R} {c : ↥(nonZeroDivisors R)} :
x * ↑c = y * ↑c ↔ x = y

In a finite ring, an element is a unit iff it is a non-zero-divisor.

theorem dvd_cancel_left_mem_nonZeroDivisors {R : Type u_1} [Ring R] {x y r : R} (hr : r ∈ nonZeroDivisors R) :
r * x ∣ r * y ↔ x ∣ y
theorem dvd_cancel_left_coe_nonZeroDivisors {R : Type u_1} [Ring R] {x y : R} {c : ↥(nonZeroDivisors R)} :
↑c * x ∣ ↑c * y ↔ x ∣ y
theorem dvd_cancel_right_mem_nonZeroDivisors {R : Type u_1} [CommRing R] {r x y : R} (hr : r ∈ nonZeroDivisors R) :
x * r ∣ y * r ↔ x ∣ y
theorem dvd_cancel_right_coe_nonZeroDivisors {R : Type u_1} [CommRing R] {x y : R} {c : ↥(nonZeroDivisors R)} :
x * ↑c ∣ y * ↑c ↔ x ∣ y