I have premises

(1)

(2)

(3)

and conclusion

( ) r

I've checked that the argument is valid.

But I still cannot find a way to show it by using rules of inference.

please...

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- September 30th 2011, 06:27 AMdeniselim17prove by rules of inference
I have premises

(1)

(2)

(3)

and conclusion

( ) r

I've checked that the argument is valid.

But I still cannot find a way to show it by using rules of inference.

please... - September 30th 2011, 06:33 AMemakarovRe: prove by rules of inference
Which exactly system of inference rules are you using? See this sticky thread.

- September 30th 2011, 05:51 PMdeniselim17Re: prove by rules of inference
something like this.

List of rules of inference - Wikipedia, the free encyclopedia - September 30th 2011, 06:23 PMPlatoRe: prove by rules of inference
- October 1st 2011, 03:10 AMemakarovRe: prove by rules of inference
Another way is to have just because r is a premise and use the Deduction theorem (or Conditional Introduction).

- October 1st 2011, 03:37 AMdeniselim17Re: prove by rules of inference
So, premise (1) and premise (2) are not really necessary here?

- October 1st 2011, 04:17 AMemakarovRe: prove by rules of inference
That's right.