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] |
6175 | External identification doesn't mean external location, as with sunburn [Davidson, by Rowlands] |
468 | Musical performance can reveal a range of virtues [Damon of Ath.] |