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D.5.5.8 displayInvariants
Procedure from library hnoether.lib (see section hnoether_lib).
- Usage:
displayInvariants(INPUT); INPUT list or poly
- Assume:
INPUT is a bivariate polynomial, or the output of develop(f) , or of
extdevelop(develop(f),n) , or (one entry of) the list hne
in the ring created by hnexpansion(f[,"ess"]) .
- Return:
none
- Display:
invariants of the corresponding branch, resp. of all branches,
in a better readable form.
- Note:
In case the Hamburger-Noether expansion of the curve f is needed
for other purposes as well it is better to calculate this first
with the aid of hnexpansion and use it as input instead of
the polynomial itself.
Example:
LIB "hnoether.lib";
ring exring=0,(x,y),dp;
list hne=develop(y4+2x3y2+x6+x5y);
displayInvariants(hne);
→ characteristic exponents : 4,6,7
→ generators of semigroup : 4,6,13
→ Puiseux pairs : (3,2)(7,2)
→ degree of the conductor : 16
→ delta invariant : 8
→ sequence of multiplicities: 4,2,2,1,1
See also:
develop;
hnexpansion;
intersection;
invariants.
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