theorem
  for R being finite array of O st [x,y] in inversions R
  holds card inversions Swap(R,x,y) < card inversions R
proof let R being finite array of O such that
A1: [x,y] in inversions R;
  card inversions Swap(R,x,y) in Segm card inversions R  by A1,Th73;
 hence card inversions Swap(R,x,y) < card inversions R  by NAT_1:44;
end;
