English

A Perturbative Multiplicity Theorem for the Borsuk-Ulam Setting

General Mathematics 2025-07-24 v1

Abstract

We prove a generalization of the classical Borsuk--Ulam Theorem under small perturbations (shaking) of the sphere. We show that for a generic perturbation of a continuous map f:S2R2f : S^2 \to \mathbb{R}^2, the number of points xS2x \in S^2 such that fϵ(x)=fϵ(x)f_\epsilon(x) = f_\epsilon(-x) becomes finite and odd, and may exceed the classical lower bound of one antipodal coincidence. In particular, we show the existence of maps with 3, 5, or 7 such points, and explain the unbounded nature of this multiplicity under higher complexity of the perturbation.

Keywords

Cite

@article{arxiv.2507.11556,
  title  = {A Perturbative Multiplicity Theorem for the Borsuk-Ulam Setting},
  author = {Karim Mansour},
  journal= {arXiv preprint arXiv:2507.11556},
  year   = {2025}
}
R2 v1 2026-07-01T04:02:52.652Z