1. (AvD) -> M
2. ~(BvO)
3. R<->(O.T)
4. ~R<->A :. ~(M->O)
|5. ~~(M->O) AIP
|6. M->O 15, DN
|7. ~B&~O 2, DM
|8. ~O&~B 7, comm
|9. ~O 8, simp
|10. ~M 6,9, MT
|11. ~(AvD) 1,10, MT
|12. ~A&~D 11, DM
|13. ~A 12, simp
|14. (~R->A)&(A->~R) 4, ME
|15. ~R->A 14, simp
|16. ~~R 15,13, MT
|17. R 16, DN
|18. [R->(O&T)]&[(O.T)->R] 3, ME
|19. R->O&T 18, simp
|20. O&T 19,17, MP
|21. O 20, simp
|22. O&~O 21,9, conj
23. ~(M->O) lines 5-22 IP
Edwin