Changes by: Xin Yu (xiny at cs.caltech.edu)
Date: 2003-04-13 04:44:19 -0700 (Sun, 13 Apr 2003)
Revision: 4421
Log message:

      Redefined normal subgroup with _extensional_ set equality (using "esquash") and proved more properties of the group kernel.
      

Changes	Path
+38 -4	metaprl/theories/itt/itt_group.ml
+1 -1	metaprl/theories/itt/itt_group.mli
+8458 -6696	metaprl/theories/itt/itt_group.prla