I want to prove that $$\{\neg P_1\to P_2\} \vdash (\neg P_2\to P_1)$$ without using the Deduction Theorem.
I'm not sure how to proceed. The class notes are all we have to work from, no text to work on similar proofs.
I want to prove that $$\{\neg P_1\to P_2\} \vdash (\neg P_2\to P_1)$$ without using the Deduction Theorem.
I'm not sure how to proceed. The class notes are all we have to work from, no text to work on similar proofs.