 reserve n for Nat;
 reserve s1 for sequence of Euclid n,
         s2 for sequence of REAL-NS n;

theorem Th17:
  for a,b being Real_Sequence holds
    IntervalSequence(a,b) is SetSequence of Euclid 1
  proof
    let a,b be Real_Sequence;
    REAL 1 = the carrier of TOP-REAL 1 by EUCLID:22
          .= the carrier of Euclid 1 by EUCLID:67;
    hence thesis;
  end;
