<< f init h >> << f weight_vector init h >> poly f,h; array of integer weight_vector; h is the initial term of the polynomial f. Example: (2 x^3 + 3 x + 1). init :: ---> 2 x^3 Example: [(x^3+1). (x h+ h^5).] {init} map :: Example: (x+1). [0 1 1 1] init :: cf. weightv << fv weight_vector init h >> << fv [weight_vector shift_vector] init h >> << fv init h >> or << hv [ ] init h >> fv is a polynomial or a vector of polynomials. h is the initial term with respect to the weight vector and the shift vector if they are given. Note: the last x variable is always assumed to be the vector index. Example: [(x,y) ring_of_differential_operators 0] define_ring [(x^2*Dx^2+2*x*Dx+x). (Dx+x).] [[(Dx) 1 (x) -1] weightv [0 -1]] init ::