k, a ring, an optional coefficient ring, by default the coefficient ring of the arrangement
Outputs:
a Boolean value, whether or not the arrangement decomposes in the sense of Papadima and Suciu [Comment. Helv. 2006]
Description
An arrangement is said to be decomposable if the derived subalgebra of its holonomy Lie algebra is a direct sum of the derived subalgebras of free Lie algebras, indexed by the rank-2 flats of the arrangement.
i1 : X3 = arrangement "X3"
o1 = {x , x , x , x + x , x + x , x + x }
1 2 3 1 2 1 3 2 3
o1 : Hyperplane Arrangement