Changes by: Xin Yu (xiny at cs.caltech.edu)
Date: 2002-03-23 23:43:47 -0800 (Sat, 23 Mar 2002)
Revision: 3544
Log message:

      Changed the definition of abelian groups completely. An abelian
      group is now defined under equivalence relations instead of equality
      relations, and there is a reduction rule for it.
      

Changes	Path
+34 -13	metaprl/theories/czf/czf_itt_abel_group.ml
+25 -1	metaprl/theories/czf/czf_itt_abel_group.mli
+851 -303	metaprl/theories/czf/czf_itt_abel_group.prla