reserve i, n for Nat,
  x, y, a for Real,
  v for Element of n-tuples_on REAL,
  p, p1, p2, p3, q, q1, q2 for Point of TOP-REAL n;

theorem Th36:
  0 <= |.p.|
proof
  |.p.| = sqrt |(p,p)| & 0 <= |(p,p)| by Th33,Th35;
  hence thesis by SQUARE_1:def 2;
end;
