Top
Back: HomJJ
Forward: primeClosure
FastBack: noether_lib
FastForward: normaliz_lib
Up: normal_lib
Top: Singular Manual
Contents: Table of Contents
Index: Index
About: About this document

D.4.15.5 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 genus(i,1) is slower than genus(i) but sometimes not.

Example:
 


Top Back: HomJJ Forward: primeClosure FastBack: noether_lib FastForward: normaliz_lib Up: normal_lib Top: Singular Manual Contents: Table of Contents Index: Index About: About this document
            User manual for Singular version 3-1-6, Dec 2012, generated by texi2html.