reserve N for Nat;
reserve n,m,n1,n2 for Nat;
reserve q,r,r1,r2 for Real;
reserve x,y for set;
reserve w,w1,w2,g,g1,g2 for Point of TOP-REAL N;
reserve seq,seq1,seq2,seq3,seq9 for Real_Sequence of N;

theorem Th23:
  |.0.TOP-REAL N.| = 0
proof
  thus |.0.TOP-REAL N.| = |.0*N.| by EUCLID:70
    .= 0 by EUCLID:7;
end;
