3 ideas
3299 | In logic identity involves reflexivity (x=x), symmetry (if x=y, then y=x) and transitivity (if x=y and y=z, then x=z) [Baillie] |
17699 | Variables are auxiliary notions, and not part of the 'eternal' essence of logic [Schönfinkel] |
3425 | Reduction has been defined as deriving one theory from another by logic and maths [Nagel,E, by Kim] |