The Zariski theorem says that for every hypersurface in a complex projectiv
e (resp. affine) space and for every generic plane in the projective (resp.
affine) space the natural embedding generates an isomorphism of the fundam
ental groups of the complements to the hypersurface in the plane and in the
space. If a family of hypersurfaces depends algebraically on parameters th
en it is not true in general that there exists a plane such that the natura
l embedding generates an isomorphism of the fundamental groups of the compl
ements to each hypersurface from this family in the plane and in the space.
But we show that in the affine case such a plane exists after a polynomial
coordinate substitution.