sm1.syz

sm1.syz([f,v,w]|proc=p)

:: computes the syzygy of f in the ring of differential operators with the variable v.

return

List

p

Number

f, v, w

List

• The return values is of the form [s,[g, m, t]]. Here s is the syzygy of f in the ring of differential operators with the variable v. g is a Groebner basis of f with the weight vector w, and m is a matrix that translates the input matrix f to the Gr\"obner basis g. t is the syzygy of the Gr\"obner basis g. In summary, g = m f and s f = 0 hold as matrices.
• The weight vectors are given by w, which can be omitted. If w is not given, the graded reverse lexicographic order will be used to compute Grobner basis.
• When a non-term order is given, the Grobner basis is computed in the homogenized Weyl algebra (See Section 1.2 of the book of SST). The homogenization variable h is automatically added.

[293] sm1.syz([[x*dx+y*dy-1,x*y*dx*dy-2],[x,y]]);
[[[y*x*dy*dx-2,-x*dx-y*dy+1]],    generators of the syzygy
 [[[x*dx+y*dy-1],[y^2*dy^2+2]],   grobner basis
  [[1,0],[y*dy,-1]],              transformation matrix
 [[y*x*dy*dx-2,-x*dx-y*dy+1]]]]

[294]sm1.syz([[x^2*dx^2+x*dx+y^2*dy^2+y*dy-4,x*y*dx*dy-1],[x,y],[[dx,-1,x,1]]]);
[[[y*x*dy*dx-1,-x^2*dx^2-x*dx-y^2*dy^2-y*dy+4]], generators of the syzygy
 [[[x^2*dx^2+h^2*x*dx+y^2*dy^2+h^2*y*dy-4*h^4],[y*x*dy*dx-h^4], GB
  [h^4*x*dx+y^3*dy^3+3*h^2*y^2*dy^2-3*h^4*y*dy]],
 [[1,0],[0,1],[y*dy,-x*dx]],     transformation matrix
 [[y*x*dy*dx-h^4,-x^2*dx^2-h^2*x*dx-y^2*dy^2-h^2*y*dy+4*h^4]]]]

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