|  |  D.4.19.5 genus Procedure from librarynormal.lib(see  normal_lib).
 
Example: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:
genus always treats projective curves and takes projective closure if input is affine 1-dim variety.
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,"nor") uses the normalization to compute delta. Usually genus(I,"nor")
is slower than genus(I) but sometimes not.
 genus(I,"pri") starts with a primary decompsition.
 
 |  | LIB "normal.lib";
ring r=0,(x,y),dp;
ideal i=y^9 - x^2*(x - 1)^9;
genus(i);
==> 0
ring r7=7,(x,y),dp;
ideal i=y^9 - x^2*(x - 1)^9;
genus(i);
==> 0
 | 
 
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