5. Prove that the following set is inconsistent in SDE, indicating which lines of the derivation show this. You may use the new inference and replacement rules of SDE to make your derivation easier,...

Extracted text: 5. Prove that the following set is inconsistent in SDE, indicating which lines of the derivation show this. You may use the new inference and replacement rules of SDE to make your derivation easier, but you need not. {P → Q, Q→ R, R→-P, P}