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7.5.2.0. Sannfslog
Procedure from library dmod.lib (see dmod_lib).
- Usage:
- Sannfslog(f [,eng]); f a poly, eng an optional int
- Return:
- ring
- Purpose:
- compute the D-module structure of basering[1/f]*f^s, where D is the Weyl algebra
- Note:
- activate this ring with the
setring command.
In the ring D[s], the ideal LD1 is generated by the elements in Ann F^s in D[s] coming from logarithmic derivations.
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),Dp;
poly F = x^4+y^5+x*y^4;
printlevel = 0;
def A = Sannfslog(F);
setring A;
LD1;
==> LD1[1]=4*x^2*Dx+5*x*Dx*y+3*x*y*Dy-16*x*s+4*y^2*Dy-20*y*s
==> LD1[2]=16*x*Dx*y^2-125*x*Dx*y-4*x^2*Dy+4*Dx*y^3+5*x*y*Dy+12*y^3*Dy-100*y^\
2*Dy-64*y^2*s+500*y*s
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