Nam Nguyen wrote: > On 30/05/2013 8:36 AM, Peter Percival wrote: >> Nam Nguyen wrote: >>> On 29/05/2013 3:25 AM, Peter Percival wrote: >>>> Nam Nguyen wrote: >>>> >>>>> Well, then, why don't you express infinity with purely logical >>>>> symbols, for us all in the 2 fora to see? Seriously, that would >>>>> be a great achievement! >>>> >>>> It is easy enough to find formulae whose only models are infinite. >>> >>> Go ahead and write down one such formula that would express infinity >>> but has only logical symbols. >> >> You know, don't you, that what a logical symbol is isn't definite. > > You're just ignorant of a basic fact, which is that _FOL does define_ > what the _logical symbols_ be!
Nor did I claim that it did. It is scholars who define what logical symbols are.
> Why don't you go and learn how Shoenfield _defined logical symbols_ > in his Section 2.4 "First-Oder Languages" (pg. 14). >
-- I think I am an Elephant, Behind another Elephant Behind /another/ Elephant who isn't really there.... A.A. Milne