Changes by: Alexei Kopylov (kopylov at cs.caltech.edu)
Date: 2001-01-29 17:05:43 -0800 (Mon, 29 Jan 2001)
Revision: 3121
Log message:
1. I removed an invalid rule from itt_isect,
derived some rule that was primitive, and
added some new derivable rules on intersection
(see theories.pdf).
2. Fix a bug in Itt_struct2.
3. Now Itt_isect and Itt_theory include Itt_struct2