Description
The derived integration modules of a Dmodule
M are the derived direct images in the category of Dmodules. This routine computes integration for projection to coordinate subspaces, where the subspace is determined by the strictly positive entries of the weight vector
w, e.g.,
{x_i = 0 : w_i > 0} if
D = C<x_1,...,x_n,d_1,...,d_n>. The input weight vector should be a list of
n numbers to induce the weight
(w,w) on
D.
The algorithm used appears in the paper 'Algorithims for Dmodules' by OakuTakayama(1999). The method is to take the Fourier transform of M, then compute the derived restriction, then inverse Fourier transform back.
i1 : R = QQ[x_1,x_2,D_1,D_2,WeylAlgebra=>{x_1=>D_1,x_2=>D_2}]
o1 = R
o1 : PolynomialRing, 2 differential variables

i2 : I = ideal(x_1, D_21)
o2 = ideal (x , D  1)
1 2
o2 : Ideal of R

i3 : Dintegration(I,{1,0})
o3 = HashTable{0 => cokernel  D_21 }
1 => 0
o3 : HashTable
