English
A ring with no zero divisors yields a cancellative monoid with zero.
Русский
Кольцо без нулевых делителей образует отменяющий моноид с нулём.
LaTeX
$$($\forall a,b,c \in \alpha, c \neq 0 \wedge ac = bc \Rightarrow a=b$) and ($\forall a,b,c \in \alpha, c \neq 0 \wedge ca = cb \Rightarrow a=b$)$$
Lean4
theorem isRegular_iff_ne_zero' [Nontrivial α] [NonUnitalNonAssocRing α] [NoZeroDivisors α] {k : α} :
IsRegular k ↔ k ≠ 0 :=
⟨fun h => by
rintro rfl
exact not_not.mpr h.left not_isLeftRegular_zero, isRegular_of_ne_zero'⟩