Re: Simple yet Profound Metatheorem

H. J. Sander Bruggink wrote:
> Charlie-Boo wrote:

> > One example will do. What is the propositional calculus wff that you
> > prove?

> Here's an intuitionistic proof:
>
> 1. | P
> |----
> 2. | P (rep)
> 3. P -> P (->I)
>
> Please show, by a "case analysis", that P->P is
> intuitionistically valid.

I didn't say anything about "intuitionistically valid". (Got it?
Good!) I said you could prove using case analysis any propositional
calculus wff that can be proven using the various rules of inference.

P => P is ~P v P

P ~P ~P v P

true false true
false true true

See, you can prove P => P using case analysis, as I said.

Now why don't YOU admit that?

New Question: Just curious - is there even a wff such that you can
prove it to be intuitionistically valid but I can't prove the wff
using case analysis?

C-B

> groente
> -- Sander

.

Relevant Pages

  • Re: Simple yet Profound Metatheorem
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  • Re: Simple yet Profound Metatheorem
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    ... intuitionistically valid. ... (I suppose you looked it up in wikipedia, by now, right?) ... calculus wff that can be proven using the various rules of inference. ...
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