reserve i for Integer,
  a, b, r, s for Real;

theorem
  a <= b & r <= s implies [:Closed-Interval-TSpace(a,b),
  Closed-Interval-TSpace(r,s):], Trectangle(a,b,r,s) are_homeomorphic
proof
  set C1 = Closed-Interval-TSpace(a,b);
  set C2 = Closed-Interval-TSpace(r,s);
  assume
A1: a <= b & r <= s;
  then reconsider
  h = R2Homeomorphism | the carrier of [:C1,C2:] as Function of [:
  C1,C2:], Trectangle(a,b,r,s) by Th35;
  take h;
  thus thesis by A1,Th36;
end;
