Solutions to Constructing proofs of arguments in QL
Proof 7
| 1. | ~(∃x)(Mx & ~Px) | premise | |
| 2. | ~(x)(Mx ⊃ ~Sx) | premise | |
| 3. | (x)(Mx ⊃ Px) | C.Q.N., 1 | |
| 4. | (∃x)(Mx & Sx) | C.Q.N. 2 | |
| 5. | Ma & Sa | E.I., 4, flag a | |
| 6. | Ma ⊃ Pa | U.I., 3 | |
| 7. | Ma | Simp, 5 | |
| 8. | Pa | M.P. 6,7 | |
| 9. | Sa | Simp 5 | |
| 10. | Sa & Pa | Conj., 8, 9 | |
| 11. | (∃x)(Sx & Px) | E.G., 10 |