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D.4.15.6 valRing
Procedure from library normaliz.lib (see normaliz_lib).
- Usage:
- valRing(intmat V);
- Return:
- The function returns a monomial ideal, to be considered as the list
of monomials generating
as an algebra over the coefficient
field.
- Background:
- A discrete monomial valuation
on
is determined by
the values of the indeterminates. This function computes the
subalgebra
for several
such valuations , . It needs the matrix
as
its input.
The function returns the ideal given by the input matrix V if one of
the options supp , triang , or hvect has been
activated.
However, in this case some numerical invariants are computed, and
some other data may be contained in files that you can read into
Singular (see showNuminvs, exportNuminvs).
- Note:
- It is of course possible that
. At present, Normaliz cannot deal with the
zero cone and will issue the (wrong) error message that the cone is not
pointed. The function also gives an error message if the matrix has the
wrong number of columns.
Example:
| LIB "normaliz.lib";
ring R=0,(x,y,z,w),dp;
intmat V0[2][4]=0,1,2,3, -1,1,2,1;
valRing(V0);
==> _[1]=y
==> _[2]=xy
==> _[3]=w
==> _[4]=xw
==> _[5]=z
==> _[6]=xz
==> _[7]=x2z
| See also:
torusInvariants;
valRingIdeal.
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