Changes by: Xin Yu (xiny at cs.caltech.edu)
Date: 2003-03-10 02:03:15 -0800 (Mon, 10 Mar 2003)
Revision: 4161
Log message:
- Proved some properties of group homomorphism.
"Membership is a type iff it is true" also causes problems in proving
"If f:A->B is a homomorphism and T is is a subgroup of B, then the
inverse image of T under f is a subgroup of A", as in
"/itt_group/groupHom_subg2/2" and "/itt_group/groupHom_subg2/3".
- Uncommented some reduce resources in itt_int_ext.
- Added several theorems about grouplikeobj and groups.