Procedures:
D.12.6.1 weierstrDiv perform Weierstrass division of g by f up to degree d D.12.6.2 weierstrPrep perform Weierstrass preparation of f up to degree d D.12.6.3 lastvarGeneral make f general of finite order w.r.t. last variable D.12.6.4 generalOrder compute integer b s.t. f is x_n-general of order b