English
If all multiplications cancel then every element is regular (both left and right).
Русский
Если все умножения отменяются, то каждый элемент регулярен (слева и справа).
LaTeX
$$$\text{IsRegular}(g)$ holds for all g whenever $\text{IsCancelMul}$ holds.$$
Lean4
/-- If all multiplications cancel then every element is regular. -/
@[to_additive /-- If all additions cancel then every element is add-regular. -/
]
theorem all [Mul R] [IsCancelMul R] (g : R) : IsRegular g :=
⟨.all g, .all g⟩