Changes by: Yegor N. Bryukhov (ybryukhov at gc.cuny.edu)
Date: 2003-12-25 23:01:25 -0800 (Thu, 25 Dec 2003)
Revision: 5216
Log message:
1.Itt_subtype - added 2 elim-style versions of subtypeTransitive.
2.Itt_ring,field - added 0<>1 condition to ring definition.
It basically says that ring should have more than one element (that's why this
conditon called isNonDegenerated).
Actually I need this condition more for fields (to prove that 0 is not in car0)
but anyway I don't think that "zero ring" is an "interesting" object.
Please let me know if you think that this condition better be in field definition.