Singular Manual: sppairs

D.6.13.7 sppairs

Procedure from library gmssing.lib (see gmssing_lib).

Usage:

sppairs(t); poly t

Assume:

characteristic 0; local degree ordering;
isolated critical point 0 of t

Return:

list spp;  spectral pairs of t
  ideal spp[1];
    number spp[1][i];  V-filtration index of i-th spectral pair
  intvec spp[2];
    int spp[2][i];  weight filtration index of i-th spectral pair
  intvec spp[3];
    int spp[3][i];  multiplicity of i-th spectral pair

Example:

LIB "gmssing.lib";
ring R=0,(x,y),ds;
poly t=x5+x2y2+y5;
sppprint(sppairs(t));
==> ((-1/2,2),1),((-3/10,1),2),((-1/10,1),2),((0,1),1),((1/10,1),2),((3/10,1)\
   ,2),((1/2,0),1)