def lll(self):
    """
    Returns an LLL-reduced form of Q (using Pari).

    EXAMPLES::

        sage: Q = QuadraticForm(ZZ, 4, range(1,11))
        sage: Q.is_definite()
        True
        sage: Q.lll()
        Quadratic form in 4 variables over Integer Ring with coefficients:
        [ 1 0 1 0 ]
        [ * 4 3 3 ]
        [ * * 6 3 ]
        [ * * * 6 ]

    """
    return self(self.matrix().LLL_gram())