I'm not able to move forward from step 4. I've tried Implication Introduction applied to 3 and 4 but nothing happens, any help is much appreciated.
2 Answers
As F.Zer commented, before you can use Implication Introduction you must first make an assumption.
You must derive r(X)
under the assumption of p(X)
, so that you may derive p(X) ⇒ r(X)
by Implication Introduction.
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Thanks a lot guys, I followed those steps and figured it out. I'm leaving the answer here just in case it helps anyone. May 13, 2020 at 13:25