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D.6.18.3 signatureNemethi

Procedure from library surfacesignature.lib (see surfacesignature_lib).

Usage:
signatureNemethi(N,f); N = integer, f = reduced poly in 2 variables, # empty or 1,2,3
- if #[1] = 1 then resolution of singularity is used
- if #[1] = 2 then spectral pairs are used
- if # is empty then both upper variants are used in parallel and the
fastest returns the result

Return:
signature of surface singularity defined by z^N + f(x,y) = 0

Remark:
computes the signature of some special surface singularities

Example:
 
LIB "surfacesignature.lib";
ring r = 0,(x,y),dp;
int N  = 3;
poly f = x15-21x14+8x13y-6x13-16x12y+20x11y2-x12+8x11y-36x10y2
+24x9y3+4x9y2-16x8y3+26x7y4-6x6y4+8x5y5+4x3y6-y8;
signatureNemethi(N,f,1);
==> -92
printlevel = 1;
signatureNemethi(N,f);
==> Resolution of singularity has been used.
==> -92