14 ideas
| 5831 | The new view is that "water" is a name, and has no definition [Schwartz,SP] |
| 13201 | ∈ says the whole set is in the other; ⊆ says the members of the subset are in the other [Enderton] |
| 13204 | The 'ordered pair' <x,y> is defined to be {{x}, {x,y}} [Enderton] |
| 13206 | A 'linear or total ordering' must be transitive and satisfy trichotomy [Enderton] |
| 13200 | Note that {Φ} =/= Φ, because Φ ∈ {Φ} but Φ ∉ Φ [Enderton] |
| 13199 | The empty set may look pointless, but many sets can be constructed from it [Enderton] |
| 13203 | The singleton is defined using the pairing axiom (as {x,x}) [Enderton] |
| 13202 | Fraenkel added Replacement, to give a theory of ordinal numbers [Enderton] |
| 13205 | We can only define functions if Choice tells us which items are involved [Enderton] |
| 5829 | We refer to Thales successfully by name, even if all descriptions of him are false [Schwartz,SP] |
| 5830 | The traditional theory of names says some of the descriptions must be correct [Schwartz,SP] |
| 16700 | In order to speak about time and successive entities, the 'present' must be enlarged [Wycliff] |
| 16701 | To be successive a thing needs parts, which must therefore be lodged outside that instant [Wycliff] |
| 5826 | The intension of "lemon" is the conjunction of properties associated with it [Schwartz,SP] |