4 ideas
9565 | Zermelo made 'set' and 'member' undefined axioms [Zermelo, by Chihara] |
3339 | For Zermelo's set theory the empty set is zero and the successor of each number is its unit set [Zermelo, by Blackburn] |
16650 | 'Unity' is a particularly difficult word, because things can have hidden unity [Duns Scotus] |
467 | A virtue is a combination of intelligence, strength and luck [Ion] |