reserve a,b,c for positive Real,
  m,x,y,z for Real,
  n for Nat,
  s,s1,s2,s3,s4,s5 for Real_Sequence;

theorem Th7:
  (x^2+y^2)/2>=x*y
proof
  (x^2+y^2)/2>=(2*x*y)/2 by Th6,XREAL_1:72;
  hence thesis;
end;
