Question 193061
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1. P &#8594; Q
2. (P • Q) &#8594; R
3. P &#8594; (R &#8594; S)
4. (R • S) &#8594; T / P &#8594; T
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5.   P                               Assumption
6.   Q                        1,5    Modus Ponens
7.   P • Q                    5,6    Conjunction 
8.   R                        2,7    Modus Ponens
9.   P • R                    5,8    Conjunction
10.  (P • R) -> S               3    Exportation
11.  S                       10,9    Modus Ponens
12.  R • S                   8,11    Conjunction
13.  T                       4,12    Modus Ponens
14.  P -> T                  5,13    Conditional Proof
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