Iof proof for Lemma not over or a:
A, B:
. (
(A 
B)) 
{(A) & (B)}
by ((Unfold `guard` 0)
CollapseTHEN (Lemma `not_over_or`))
C.| 12,41 |
A, B:. ((A B)) {(A) & (B)}
by ((Unfold `guard` 0)
CollapseTHEN (Lemma `not_over_or`))
C.
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| Lemmas |