Changes by: Aleksey Nogin (nogin at cs.caltech.edu)
Date: 2005-11-04 10:05:14 -0800 (Fri, 04 Nov 2005)
Revision: 8096
Log message:

      - Updated the elimination rules for Union so that they better preserve binding
        names.
      
      - Fixed the proof of tunionElimination_disjoint