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D.6.7.21 spgamma

Procedure from library gmssing.lib (see gmssing_lib).

Usage:
spgamma(sp); list sp

Return:
number gamma; gamma invariant of spectrum sp

Example:
 
LIB "gmssing.lib";
ring R=0,(x,y),ds;
list sp=list(ideal(-1/2,-3/10,-1/10,0,1/10,3/10,1/2),intvec(1,2,2,1,2,2,1));
spprint(sp);
==> (-1/2,1),(-3/10,2),(-1/10,2),(0,1),(1/10,2),(3/10,2),(1/2,1)
spgamma(sp);
==> 1/240