DHom -- D-homomorphisms between holonomic D-modules

• Usage:

  DHom(M,N), DHom(M,N,w), DHom(I,J)

• Inputs:
  • M, a module, over the Weyl algebra D
  • N, a module, over the Weyl algebra D
  • I, an ideal, which represents the module M = D/I
  • J, an ideal, which represents the module N = D/J
  • w, a list, a positive weight vector
• Optional inputs:
  • Strategy => ..., default value Schreyer,
• Outputs:
  • a hash table, a basis of D-homomorphisms between holonomic D-modules M and N

i1 : W = QQ[x, D, WeylAlgebra=>{x=>D}]

o1 = W

o1 : PolynomialRing, 1 differential variable(s)

i2 : M = W^1/ideal(D-1)

o2 = cokernel | D-1 |

                            1
o2 : W-module, quotient of W

i3 : N = W^1/ideal((D-1)^2)

o3 = cokernel | D2-2D+1 |

                            1
o3 : W-module, quotient of W

i4 : DHom(M,N)

o4 = {| -xD+x+1 |, | -D+1 |}

o4 : List