
D.6.12.3 QuotientEquations
Procedure from library qhmoduli.lib (see qhmoduli_lib).
 Usage:
 QuotientEquations(G,action,emb [, opt]); ideal G,action,emb;int opt
 Purpose:
 compute the quotient of the variety given by the parameterization
'emb' by the linear action 'action' of the algebraic group G.
 Assume:
 'action' is linear, G must be finite if the Reynolds operator is
needed (i.e., NullCone(G,action) returns some noninvariant polys)
 Return:
 polynomial ring over a simple extension of the ground field of the
basering, containing the ideals 'id' and 'embedid'.
 'id' contains the equations of the quotient, if opt = 1;
if opt = 0, 2, 'id' contains generators of the coordinate ring R
of the quotient (Spec(R) is the quotient)
 'embedid' = 0, if opt = 1;
if opt = 0, 2, it is the ideal defining the equivariant embedding
 Options:
 1 compute equations of the quotient,
2 use a primary decomposition when computing the Reynolds operator,
to combine options, add their value, default: opt =3.
