1. A -> (C V B)
2. ~(D V C)
3. ~(E V B) /∴ ~A
| 4. ~~A AIP
| 5. A 4, DN
| 6. C V B 1,5, MP
| 7. ~D & ~C 2, DM
| 8. ~E & ~B 3, DM
| 9. ~B & ~E 8, comm.
|10. ~B 9, simp.
|11. B V C 6, comm.
|12. C 11,10, DS
|13. ~C & ~D 7, comm.
|14. ~C 13, simp.
|15. C & ~C 12,14 conj
16. ~A 4-15 IP
Edwin