reserve k,j,n for Nat,
  r for Real;
reserve x,x1,x2,y for Element of REAL n;
reserve f for real-valued FinSequence;
reserve p,p1,p2,p3 for Point of TOP-REAL n,
  x,x1,x2,y,y1,y2 for Real;
reserve p,p1,p2 for Point of TOP-REAL 2;

theorem
  1<=n implies 1<=|. (1.REAL n) .|
proof
  assume
A1: 1<=n;
  |.1.REAL n.|=sqrt n by Th45;
  hence thesis by A1,SQUARE_1:18,26;
end;
