1. T=R Premise

2.(~R→~T)→(P.~S) Premise

…………

~SvT

Proof

3. (T→R).(R→T) 1, Equivalence

4. T→R 3, Equivalence

5. ~T v R 4, Equivalence

6. (Rv~T)→ (P.~S) 2,Equivalence

7. P.~S 5,6 Modus Ponen

8. ~S 7, Simplification

9. ~SvT 8, Addition

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