public static boolean checkGroupElem(BigInteger g){
  return !(g.compareTo(BigInteger.valueOf(2)) > 0 && g.compareTo(SM.MODULUS_MINUS_2) < 0);
}

public static boolean checkGroupElem ( BigInteger g ) { return ! ( g . compareTo ( BigInteger . valueOf ( 2 ) ) > 0 && g . compareTo ( SM . MODULUS_MINUS_2 ) < 0 ) ; }
check that an biginteger is in the right range to be a ( non - unit ) group element
