Re: Looking for Undecidable Propositions in Systems without a certain amount of arthimetic.

Am Fri, 15 Aug 2008 13:15:02 -0700 (PDT) schrieb Scott:


S -> Ex(x ^ ~x))

This is not a wff in any standard system of FOPL. There we usually don't
(and can't) "negate" terms (or variables). Moreover to connect _object
variables_ with "sentential connectives" is not possible there (i.e. does
not occur in a wff). Actually, it doesn't make any sense at meta-level.

See:
http://mathworld.wolfram.com/First-OrderLogic.html


B.
.

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