4.22.3.30 semigroupGenerator

Syntax:

semigroupGenerator( cone c )

Type:

intvec

Purpose:

if dimension(c)=linealityDimension(c)+1, then the quotient lattice of Z^n intersected with the span and Z^n intersected with the lineality space is Z^1 and the class of the cone is a semigroup. returns a generator of that semigroup. (like quotientLatticeBasis(cone c), but as intvec)

Example:

LIB"gfanlib.so"; intmat M[3][2]= 1,0, 0,1, -1,0; cone c=coneViaPoints(M); semigroupGenerator(c); ==> 0,1