init

<< 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 ::



Nobuki Takayama 2020-11-24