reserve y for set,
  x,r,a,b for Real,
  n for Element of NAT,
  Z for open Subset of REAL,
  f,f1,f2,f3 for PartFunc of REAL,REAL;

theorem Th1:
  x #Z 2=x^2
proof
  x #Z 2 = x |^ 2 by PREPOWER:36
    .= x^2 by NEWTON:81;
  hence thesis;
end;
