1. T -> [(A * R) -> (S v ~A)] 2. ~S /(T * R) -> ~A ------------------------------------------ 3. T -> [~(A * R) v (S v ~A)] 1 Material Implication 4. T -> [(~A v ~R) v (S v ~A)] 3 De Morgan's Law 5. T -> [(~R v ~A) v (~A v S)] 4 Commutation 6. T -> [(~R v (~A v ~A)) v S] 5 Association 7. T -> [(~R v ~A) v S] 6 Tautology 8. T -> [(~A v ~R) v S] 7 Commutation 9. T -> [~A v (~R v S)] 8 Association 10. T -> [A -> (~R v S)] 9 Material Implication 11. (T * A) -> (~R v S) 10 Exportation 12. ~(T * A) v (~R v S) 11 Material Implication 13. (~T v ~A) v (~R v S) 12 De Morgan's Law 14. [(~T v ~A) v ~R] v S 13 Association 15. (~T v ~A) v ~R 14,2 Disjunctive Syllogism 16. ~T v (~A v ~R) 15 Association 17. ~T v (~R v ~A) 16 Commutation 18. (~T v ~R) v ~A 17 Association 19. ~(T * R) v ~A 18 De Morgan's Law 20. (T * R) -> ~A 19 Material Implication