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D.5.4.20 spsemicont
Procedure from library gaussman.lib (see gaussman_lib).
- Usage:
spsemicont(sp0,sp,k[,1]); list sp0, list sp
- Return:
list l; intvec l[i]; if the spectra sp0 occur with multiplicities k in a deformation of a [quasihomogeneous] singularity with spectrum sp then k<=l[i]
Example:
LIB "gaussman.lib"; ring R=0,(x,y),ds; list sp0=list(ideal(-1/2,-3/10,-1/10,0,1/10,3/10,1/2),intvec(1,2,2,1,2,2,1)); spprint(sp0); → (-1/2,1),(-3/10,2),(-1/10,2),(0,1),(1/10,2),(3/10,2),(1/2,1) list sp1=list(ideal(-1/6,1/6),intvec(1,1)); spprint(sp1); → (-1/6,1),(1/6,1) list sp2=list(ideal(-1/3,0,1/3),intvec(1,2,1)); spprint(sp2); → (-1/3,1),(0,2),(1/3,1) list sp=sp1,sp2; list l=spsemicont(sp0,sp); l; → [1]: → 3 → [2]: → 2,1 spissemicont(spsub(sp0,spmul(sp,l[1]))); → 1 spissemicont(spsub(sp0,spmul(sp,l[1]-1))); → 1 spissemicont(spsub(sp0,spmul(sp,l[1]+1))); → 0 |