(self)
return all(self[i, j].is_zero
            for i in range(self.rows)
            for j in range(i + 2, self.cols))
r"""Checks if the matrix is in the lower-Hessenberg form.

        The lower hessenberg matrix has zero entries
        above the first superdiagonal.

        Examples
        ========

        >>> from sympy.matrices import Matrix
        >>> a = Matrix([[1, 2, 0, 0], [5, 2, 3, 0], [3, 4, 3, 7], [5, 6, 1, 1]])
        >>> a
        Matrix([
        [1, 2, 0, 0],
        [5, 2, 3, 0],
        [3, 4, 3, 7],
        [5, 6, 1, 1]])
        >>> a.is_lower_hessenberg
        True

        See Also
        ========

        is_upper_hessenberg
        is_lower
r"""Checks if the matrix is in the lower-Hessenberg form.
r Checks if the matrix is in the lower - Hessenberg form .
def is_lower_hessenberg(self):
        r"""Checks if the matrix is in the lower-Hessenberg form.

        The lower hessenberg matrix has zero entries
        above the first superdiagonal.

        Examples
        ========

        >>> from sympy.matrices import Matrix
        >>> a = Matrix([[1, 2, 0, 0], [5, 2, 3, 0], [3, 4, 3, 7], [5, 6, 1, 1]])
        >>> a
        Matrix([
        [1, 2, 0, 0],
        [5, 2, 3, 0],
        [3, 4, 3, 7],
        [5, 6, 1, 1]])
        >>> a.is_lower_hessenberg
        True

        See Also
        ========

        is_upper_hessenberg
        is_lower
        """
        return all(self[i, j].is_zero
            for i in range(self.rows)
            for j in range(i + 2, self.cols))
def is_lower_hessenberg ( self ) : return all ( self [ i , j ] . is_zero for i in range ( self . rows ) for j in range ( i + 2 , self . cols ) )