10 ideas
9540 | A 'value-assignment' (V) is when to each variable in the set V assigns either the value 1 or the value 0 [Hughes/Cresswell] |
9541 | The Law of Transposition says (P→Q) → (¬Q→¬P) [Hughes/Cresswell] |
9543 | The rules preserve validity from the axioms, so no thesis negates any other thesis [Hughes/Cresswell] |
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] |
9544 | A system is 'weakly' complete if all wffs are derivable, and 'strongly' if theses are maximised [Hughes/Cresswell] |
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] |
12887 | A whole must have one characteristic, an internal relation, and a structure [Rescher/Oppenheim] |