6 ideas
8920 | Equivalence relations are reflexive, symmetric and transitive, and classify similar objects [Lipschutz] |
17879 | Axiomatising set theory makes it all relative [Skolem] |
13536 | Skolem did not believe in the existence of uncountable sets [Skolem] |
17878 | If a 1st-order proposition is satisfied, it is satisfied in a denumerably infinite domain [Skolem] |
17880 | Integers and induction are clear as foundations, but set-theory axioms certainly aren't [Skolem] |
17881 | Mathematician want performable operations, not propositions about objects [Skolem] |