INSTRUCTIONS: This assignment is due March 5th 1999, in class. Groups may hand in a single assignment paper. The maximum group size is 4.
The assignments must have the name and York number of all group members listed at the top of the paper.
Any axiom may be used. Lower numbered theorems may be used in the proof of a higher numbered theorem.
Hence by derived inference rule for number 2, .
Hence by TRANSITIVITY 3 times and EQUANIMITY . Hence by the Deduction Theorem it follows that .
Subs . TRANSITIVITY twice and EQUANIMITY gives that .
Subs p:= false. TRANSITIVITY three times and EQUANIMITY gives that .
Hence by Proof by Cases it follows that .