theorem
  seq1 is bounded & seq2 is bounded implies seq1 - seq2 is bounded
proof
  assume that
A1: seq1 is bounded and
A2: seq2 is bounded;
A3: seq1 - seq2 = seq1 + (- seq2) by CSSPACE:64;
  - seq2 is bounded by A2,Th75;
  hence thesis by A1,A3,Th74;
end;
