Question 1119188
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1.   [~S v ~(~T • ~U)]                          Premise
2.:  [~S v (T v U)]                             Conditional Proof (CP) #1,  1, DeMorgan's (DeM)
3.:  [(~S v T) v U)]                            2, Associative Property (ASSOC)
4.:  [(S —> T) v U)]                            3, Relation of Implication (IMPL)
5.:  [U v (S —> T))]                            4, Commutative Property (COMM)
6.:  [~U —> (S —> T)]                           5, IMPL
7.::  S —> T                                    CP #2, assumption #1
8.::  ~T                                        CP #2, assumption #2
9.::  ~S                                        8,7 Modus Tollens (MT)
10.:: (S —> T)  == (~T —> ~S)                   7-9, CP #2 (shows logical equivalence) 
11.:  [~U —> (~T —> ~S)]                        6,10 logical equivalence 
12. [~S v ~(~T • ~U)] —>  [~U —> (~T —> ~S)]    1-11, CP #1