
theorem Th2:
  for p be Safe Prime holds p >= 5
proof
  let p be Safe Prime;
  consider q be Prime such that
A1: 2*q+1 = p by Def1;
  q > 1 by INT_2:def 4;
  then q >= 1+1 by NAT_1:13;
  then 2*q >= 2*2 by XREAL_1:64;
  then 2*q+1 >= 4+1 by XREAL_1:7;
  hence thesis by A1;
end;
