INSTRUCTIONS: Construct a regular proof to derive the conclusion of the following argument:
1. (A & U) < > ~R
2. ~(~R v ~A)
/ ~U
3. ~~R & ~~A 2, DeMorgan's theorem
4. R & A 3, Double negation
5. R 4, Simplification
6. [(A & U) > ~R] & [~R > (A & U)] 1, Material equivalence
7. (A & U) > ~R 6, Simplification
8. ~~R > ~(A & U) 7, Transposition
9. R > ~(A & U) 8, Double negation
10. ~(A & U) 9,5 Modus ponens
11. ~A v ~U 10, DeMorgan's theorem
12. A & R 4, Commutation
13. A 12, Simplification
14. ~~A 13, Double negation
15. ~U 11,14 Disjunctive syllogism
Edwin