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D.6.9.4 param
Procedure from library hnoether.lib (see hnoether_lib).
- Usage:
- param(L [,s]); L list, s any type (optional)
- Assume:
- L is the output of
develop(f) , or of
extdevelop(develop(f),n) , or (one entry in) the list of HN
data created by hnexpansion(f[,"ess"]) .
- Return:
- If L are the HN data of an irreducible plane curve singularity f: a
parametrization for f in the following format:
- if only the list L is given, the result is an ideal of two
polynomials p[1],p[2]: if the HNE was finite then f(p[1],p[2])=0};
if not, the true parametrization will be given by two power series,
and p[1],p[2] are truncations of these series.
- if the optional parameter s is given, the result is a list l:
l[1]=param(L) (ideal) and l[2]=intvec with two entries indicating
the highest degree up to which the coefficients of the monomials in
l[1] are exact (entry -1 means that the corresponding parametrization
is exact).
If L collects the HN data of a reducible plane curve singularity f,
the return value is a list of parametrizations in the respective
format.
- Note:
- If the basering has only 2 variables, the first variable is chosen
as indefinite. Otherwise, the 3rd variable is chosen.
Example:
See also:
develop;
extdevelop.
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