18 ideas
13030 | Extensionality: ∀x ∀y (∀z (z ∈ x ↔ z ∈ y) → x = y) [Kunen] |
13032 | Pairing: ∀x ∀y ∃z (x ∈ z ∧ y ∈ z) [Kunen] |
13033 | Union: ∀F ∃A ∀Y ∀x (x ∈ Y ∧ Y ∈ F → x ∈ A) [Kunen] |
13037 | Infinity: ∃x (0 ∈ x ∧ ∀y ∈ x (S(y) ∈ x) [Kunen] |
13038 | Power Set: ∀x ∃y ∀z(z ⊂ x → z ∈ y) [Kunen] |
13034 | Replacement: ∀x∈A ∃!y φ(x,y) → ∃Y ∀X∈A ∃y∈Y φ(x,y) [Kunen] |
13039 | Foundation:∀x(∃y(y∈x) → ∃y(y∈x ∧ ¬∃z(z∈x ∧ z∈y))) [Kunen] |
13036 | Choice: ∀A ∃R (R well-orders A) [Kunen] |
18270 | Choice suggests that intensions are not needed to ensure classes [Coffa] |
13029 | Set Existence: ∃x (x = x) [Kunen] |
13031 | Comprehension: ∃y ∀x (x ∈ y ↔ x ∈ z ∧ φ) [Kunen] |
13040 | Constructibility: V = L (all sets are constructible) [Kunen] |
13007 | Archimedes defined a straight line as the shortest distance between two points [Archimedes, by Leibniz] |
18465 | An 'equivalence' relation is one which is reflexive, symmetric and transitive [Kunen] |
18263 | The semantic tradition aimed to explain the a priori semantically, not by Kantian intuition [Coffa] |
18272 | Platonism defines the a priori in a way that makes it unknowable [Coffa] |
18266 | Mathematics generalises by using variables [Coffa] |
18279 | Relativity is as absolutist about space-time as Newton was about space [Coffa] |