Re: Proving (or P (not P)) in a natural deduction systemThis is a discussion on Re: Proving (or P (not P)) in a natural deduction system within the Object forums in Theory and Concepts category; I figured it out. It's very similar to the tough problem in the book: 1. Show (or P (not P)) (IP 2 2 3) 2. (not (or P (not P))) Asn 3. Show (or (not P) P) (OI 4) 4. Show (not P) (NI 5 2 6) 5. P Asn 6. Show (or (not P) P) (OI 5) On Apr 18, 5:18 am, namin <na...@mit.edu> wrote: > I am using the natural deduction system based on Kalish and Montague > from the book, Building Problem Solver (pp. 92 - 99). > You can view the relevant pages here: http://books.google.com/books?id=Mra...frontcover&sou ... ... | ||||||||
| | ||||||||
| ||||||||
| Register | FAQ | Calendar | Search | Today's Posts | Mark Forums Read |
|
#1
04-19-2008, 12:11 AM
| |||
| |||
 Re: Proving (or P (not P)) in a natural deduction system I figured it out. It's very similar to the tough problem in the book: 1. Show (or P (not P)) (IP 2 2 3) 2. (not (or P (not P))) Asn 3. Show (or (not P) P) (OI 4) 4. Show (not P) (NI 5 2 6) 5. P Asn 6. Show (or (not P) P) (OI 5) On Apr 18, 5:18 am, namin <na...@mit.edu> wrote: > I am using the natural deduction system based on Kalish and Montague > from the book, Building Problem Solver (pp. 92 - 99). > You can view the relevant pages here:http://books.google.com/books?id=Mra...frontcover&sou... > > I am trying to prove the tautology (or P (not P)) using only the proof > rules of the system, which are Indirect Proof, Not/And/Or/Conditional/ > Bicontiditonal Eliminations/Intoductions. (See the pages above for > details.) > > Is it possible to prove (or P (not P)) or is there a reason why it > cannot be proved? > > Thanks. ~n  |
 |
| Thread Tools | |
| Display Modes | |
Linear Mode
