1. (K v S) v (T v W) 2. ~S + [T v ~(O v Z)] 3. K > ~(T v ~Z) /∴ T v W 4. | ~(T v W) Assumption for Indirect Proof 5. | (T v W) v (K v S) 1, Commutation 6. | K v S 5,4 Disjunctive Syllogism 7. | S v K 6, Commutation 8. | ~S 2, Simplification 9. | K 7,8, Disjunctive Syllogism 10. | ~(T v ~Z) 3,9, Modus Ponens 11. | ~T + ~~Z 10, DeMorgan's Law 12. | ~T + Z 11, Double Negation 13. | Z + ~T 12, Commutation 14. | Z 13, Simplification 15. | [T v ~(O v Z)] + ~S 2, Commutation 16. | T v ~(O v Z) 15, Simplification 17. | ~T 12, Simplification 18. | ~(O v Z) 16,17, Disjunctive Syllogism 19. | ~O + ~Z 17, DeMorgan's Law 20. | ~Z + ~O 18, Commutation 21. | ~Z 19, Simplification 22. | Z + ~Z 13,19, Conjunction 23. T v W Lines 4-23 Indirect Proof Edwin