theorem Th26:
  G is independent implies All('not' All(a,A,G),B,G) '<' 'not' All(
  All(a,B,G),A,G)
proof
  assume G is independent;
  then All(All(a,B,G),A,G) = All(All(a,A,G),B,G) by PARTIT_2:15;
  then
  All('not' All(a,A,G),B,G) = 'not' Ex(All(a,A,G),B,G) & All(All(a,B,G),A,
  G) '<' Ex(All(a,A,G),B,G) by Th8,BVFUNC_2:19;
  hence thesis by PARTIT_2:11;
end;
