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7.7.3.0. SannfsOT
Procedure from library dmod.lib (see dmod_lib).
- Usage:
- SannfsOT(f [,eng]); f a poly, eng an optional int
- Return:
- ring
- Purpose:
- compute the D-module structure of basering[1/f]*f^s, according to the
1st step of the algorithm by Oaku and Takayama in the ring D[s]
- Note:
- activate the output ring with the
setring command.
In the output ring D[s], the ideal LD (which is NOT a Groebner basis)
is the needed D-module structure.
If eng <>0, std is used for Groebner basis computations,
otherwise, and by default slimgb is used.
If printlevel=1, progress debug messages will be printed,
if printlevel>=2, all the debug messages will be printed.
Example:
| LIB "dmod.lib";
ring r = 0,(x,y,z),Dp;
poly F = x^3+y^3+z^3;
printlevel = 0;
def A = SannfsOT(F);
setring A;
LD;
==> LD[1]=x*Dx+y*Dy+z*Dz-3*s
==> LD[2]=z^2*Dy-y^2*Dz
==> LD[3]=z^2*Dx-x^2*Dz
==> LD[4]=y^2*Dx-x^2*Dy
==> LD[5]=x^3*Dz+y^3*Dz+z^3*Dz-3*z^2*s
==> LD[6]=x^3*Dy+y^3*Dy+y^2*z*Dz-3*y^2*s
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