3 ideas
17751 | Gödel proved the completeness of first order predicate logic in 1930 [Gödel, by Walicki] |
8920 | Equivalence relations are reflexive, symmetric and transitive, and classify similar objects [Lipschutz] |
5845 | Niceratus learnt the whole of Homer by heart, as a guide to goodness [Xenophon] |