(i) | $X \neq \emptyset$ |
(i) | $X \neq \emptyset$ |
(i) | $X \neq \emptyset$ |
(i) | $X \neq \emptyset$ |
▶ | D1821: Map minimum |
▶ | D297: Set lower bound |
▶ | R1120: Antitonicity of minimum |
▶ | R1083: Minimal element is minimum element in ordered set |
▶ | R1076: Minimum element is unique |