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D.6.18.5 StabEqnId
Procedure from library qhmoduli.lib (see qhmoduli_lib).
- Usage:
- StabEqn(I, w); I ideal, w intvec
- Purpose:
- compute the equations of the isometry group of the ideal I,
each generator of I is fixed by the stabilizer.
- Assume:
- I semiquasihomogeneous ideal w.r.t. 'w' with an isolated singularity at 0
- Return:
- list of two rings 'S1', 'S2'
- 'S1' contians the equations of the stabilizer (ideal 'stabid')
- 'S2' contains the action of the stabilizer (ideal 'actionid')
- Global:
- varSubsList, contains the index j s.t. t(i) -> t(i)t(j) ...
Example:
| | LIB "qhmoduli.lib";
ring B = 0,(x,y,z), ls;
ideal I = x2,y3,z6;
intvec w = 3,2,1;
list stab = StabEqnId(I, w);
==> // ** redefining zz (int zz = 1;) qhmoduli.lib::StabEqnId:630
def S1 = stab[1]; setring S1; stabid;
==> stabid[1]=s(1)^2-1
==> stabid[2]=s(2)^3-1
==> stabid[3]=s(3)^6-1
def S2 = stab[2]; setring S2; actionid;
==> actionid[1]=s(1)*x
==> actionid[2]=s(2)*y
==> actionid[3]=s(3)*z
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