Freeness in families of arrangements
Establish a general theorem determining whether non-freeness of the fibers of a family of hyperplane arrangements implies non-freeness of the total-space divisor, particularly for nontrivial families such as the family of generic arrangements of five planes in C^3 parametrized by their two-dimensional moduli space.
References
Non-freeness of the fibres does not formally imply non-freeness of the total space of a non-trivial family. We do not know a general statement of this kind.
— Geometry of some determinantal arrangements
(2610.13291 - Janasz, 9 Oct 2026) in Remark 4.8, Section 5 (Transversal arrangements at rank-two points of D_{3,5})