display all the ideas for this combination of texts
4 ideas
17924 | Excluded middle says P or not-P; bivalence says P is either true or false [Colyvan] |
17743 | De Morgan introduced a 'universe of discourse', to replace Boole's universe of 'all things' [De Morgan, by Walicki] |
17929 | Löwenheim proved his result for a first-order sentence, and Skolem generalised it [Colyvan] |
17930 | Axioms are 'categorical' if all of their models are isomorphic [Colyvan] |