English

Section problems for configurations of points on the Riemann sphere

Geometric Topology 2020-12-16 v1 Algebraic Geometry Group Theory

Abstract

This paper contains a suite of results concerning the problem of adding mm distinct new points to a configuration of nn distinct points on the Riemann sphere, such that the new points depend continuously on the old. Altogether, the results of the paper provide a complete answer to the following question: given n5n \ne 5, for which mm can one continuously add mm points to a configuration of nn points? For n6n \ge 6, we find that mm must be divisible by n(n1)(n2)n(n-1)(n-2), and we provide a construction based on the idea of cabling of braids. For n=3,4n = 3,4, we give some exceptional constructions based on the theory of elliptic curves.

Keywords

Cite

@article{arxiv.1807.10171,
  title  = {Section problems for configurations of points on the Riemann sphere},
  author = {Lei Chen and Nick Salter},
  journal= {arXiv preprint arXiv:1807.10171},
  year   = {2020}
}

Comments

25 pages with 4 figures

R2 v1 2026-06-23T03:15:31.443Z