D.4.6.3 genus
.............
Procedure from library normal.lib (see normal_lib).

Usage:
genus(I) or genus(i,1); I a 1-dimensional ideal

Return:
an integer, the geometric genus p_g = p_a - delta of the projective
curve defined by I, where p_a is the arithmetic genus.

Note:
delta is the sum of all local delta-invariants of the singularities,
i.e. dim(R'/R), R' the normalization of the local ring R of the
singularity.

genus(i,1) uses the normalization to compute delta. Usually this
is slow but sometimes not.

Example:
LIB "normal.lib";
ring r=0,(x,y),dp;
ideal i=y^9 - x^2*(x - 1)^9;
genus(i);
==> 0

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&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; User manual for <a href="http://www.singular.uni-kl.de/"><i>Singular</i></a> version 2-0-4, October 2002,
generated by <a href="http://www.gnu.org/software/texinfo/"><i>texi2html</i></a>.
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