D.5.8.12 qhspectrum

Procedure from library sing.lib (see sing_lib).

Usage:

qhspectrum(f,w); f=poly, w=intvec;

Assume:

f is a weighted homogeneous isolated singularity w.r.t. the weights given by w; w must consist of as many positive integers as there are variables of the basering

Compute:

the spectral numbers of the w-homogeneous polynomial f, computed in a ring of characteristic 0

Return:

intvec d,s1,...,su where:
d = w-degree(f) and si/d = i-th spectral-number(f)
No return value if basering has parameters or if f is no isolated singularity, displays a warning in this case

Example:

LIB "sing.lib";
ring r;
poly f=x3+y5+z2;
intvec w=10,6,15;
qhspectrum(f,w);
→ 30,1,7,11,13,17,19,23,29
// the spectrum numbers are:
// 1/30,7/30,11/30,13/30,17/30,19/30,23/30,29/30