English
Similarly, NoZeroDivisors implies that right non-zero divisors are exactly the nonzero elements: nonZeroDivisorsRight M0 = { x : M0 | x ≠ 0 }.
Русский
Аналогично, если нет нулевых делителей, правая часть не нулевых делителей совпадает с ненулевыми элементами: nonZeroDivisorsRight M0 = { x : M0 | x ≠ 0 }.
LaTeX
$$$\operatorname{nonZeroDivisorsRight}(M_0) = \{ x : M_0 \mid x \neq 0 \}$$$
Lean4
@[simp]
theorem coe_nonZeroDivisorsRight_eq [NoZeroDivisors M₀] [Nontrivial M₀] : nonZeroDivisorsRight M₀ = {x : M₀ | x ≠ 0} :=
by
ext x
simp only [SetLike.mem_coe, mem_nonZeroDivisorsRight_iff, mul_eq_zero, forall_eq_or_imp, true_and, Set.mem_setOf_eq]
refine ⟨fun h ↦ ?_, fun hx y hx' ↦ by contradiction⟩
contrapose! h
exact ⟨1, h, one_ne_zero⟩