Published November 2025 | Version Published
Journal Article

Everywhere unbalanced configurations

  • 1. ROR icon California Institute of Technology

Abstract

An old problem in discrete geometry, originating with Kupitz, asks whether there is a fixed natural number k such that every finite set of points in the plane has a line through at least two of its points where the number of points on either side of this line differ by at most k. We give a negative answer to a natural variant of this problem, showing that for every natural number k there exists a finite set of points in the plane together with a pseudoline arrangement such that each pseudoline contains at least two points and there is a pseudoline through any pair of points where the number of points on either side of each pseudoline differ by at least k. Moreover, we may find such a configuration with at most 2²ck points, which, by a result of Pinchasi, is best possible up to the value of the constant c.

Copyright and License

Funding

Research supported by NSF Awards DMS-2054452 and DMS-2348859. Research partially supported by an NUS Overseas Graduate Scholarship.

Additional details

Related works

Is new version of
Discussion Paper: arXiv:2308.02466 (arXiv)

Funding

National Science Foundation
DMS-2054452
National Science Foundation
DMS-2348859
National University of Singapore

Dates

Accepted
2025-07-09
Available
2025-07-30
Available online
Available
2025-07-30
Version of record

Caltech Custom Metadata

Caltech groups
Division of Physics, Mathematics and Astronomy (PMA)
Publication Status
Published