def __init__(self, A, polynomials, embedding_center=None,
                 embedding_codomain=None, embedding_images=None):
        """
        EXAMPLES::

            sage: A.<x,y,z> = AffineSpace(QQ, 3)
            sage: A.subscheme([y^2-x*z-x*y])
            Closed subscheme of Affine Space of dimension 3 over Rational Field defined by:
              -x*y + y^2 - x*z
        """
        AlgebraicScheme_subscheme.__init__(self, A, polynomials)
        if embedding_images is not None:
            self._embedding_morphism = self.hom(embedding_images, embedding_codomain)
        elif A._ambient_projective_space is not None:
            self._embedding_morphism = self.projective_embedding \
                (A._default_embedding_index, A._ambient_projective_space)
        if embedding_center is not None:
            self._embedding_center = self.point(embedding_center)