compress(Arrangement) -- extract nonzero equations

Synopsis

Function: compress
Usage:

compress A
Inputs:
- A, a hyperplane arrangement,
Outputs:
- a hyperplane arrangement, a loopless arrangement

Description

An arrangement is loopless if none of its forms are identically 0. This method returns the arrangement defined by the non-identically-zero forms of A.

i1 : R = QQ[x,y,z]

o1 = R

o1 : PolynomialRing

i2 : A = dual arrangement {x,y,x-y,z} -- the last element of this arrangement is 0

o2 = {-x , x , x , 0}
        1   1   1

o2 : Hyperplane Arrangement

i3 : compress A

o3 = {-x , x , x }
        1   1   1

o3 : Hyperplane Arrangement

Ways to use this method: