Home Online Manual
Back: realizationDim
Forward: realizationDimPoly
Up: realizationMatroids_lib
Top: Singular Manual
Contents: Table of Contents
Index: Index
About: About this document

D.13.3.2 irrRealizationDim

Procedure from library realizationMatroids.lib (see realizationMatroids_lib).

irrRealizationDim(I,C); where I is a homogeneous linear ideal defining the projective plane Y = V(I) and C is a list of intvectors such that each intvector represents a one-dimensional cone in the tropical fan curve whose irreducible relative realizability should be checked. This representation is done in the following way: a one-dimensional cone K is represented by a vector w whose equivalence class [w] in R^n/<1> can be written as [w] = m*[v] where [v] is the primitive generator of K and m is the weight of K.

the dimension of the irreducible relative realization space of C with respect to Y, and -1 if the irreducible realization space is empty.

LIB "realizationMatroids.lib";
ring r = 0,(x(1..4)),dp;
ideal I = x(1)+x(2)+x(3)+x(4);
list C = list(intvec(2,2,0,0),intvec(0,0,2,2));
//C represents the tropical fan curve which consists of the cones
//cone([(1,1,0,0)]) and cone([(1,1,0,0)]), both with weight 2
==> 0
==> -1