helphome pageduck scriptspecificationfirst proof pagepage 4page 3 1 2 3 4

Behavioral Properties of Set
The De Morgen laws


We want to prove
       ( S1  S2  : Set  ) neg(S1 U S2) = neg(S1) & neg(S2)
and
       ( S1  S2  : Set  ) neg(S1 & S2) = neg(S1) U neg(S2) .
Conjunction elimination yields 2 subgoals:
  1. ( S1  S2  : Set  ) neg(S1 U S2) = neg(S1) & neg(S2)
  2. ( S1  S2  : Set  ) neg(S1 & S2) = neg(S1) U neg(S2)

And thus the main goal is proved.

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       This page was generated by Kumo on Tue Feb 13 11:31:33 PST 2001.