(i) | \begin{equation} X \neq \emptyset \end{equation} |
(1) | $\forall \, x \in X : y x = x$ | (D537: Left identity element) |
(2) | $\forall \, x \in X : x y = x$ | (D538: Right identity element) |
(i) | \begin{equation} X \neq \emptyset \end{equation} |
(1) | $\forall \, x \in X : y x = x$ | (D537: Left identity element) |
(2) | $\forall \, x \in X : x y = x$ | (D538: Right identity element) |