English

Partitions of $n$-valued maps

General Topology 2021-01-26 v1

Abstract

An nn-valued map is a set-valued continuous function ff such that f(x)f(x) has cardinality nn for every xx. Some nn-valued maps will "split" into a union of nn single-valued maps. Characterizations of splittings has been a major theme in the topological theory of nn-valued maps. In this paper we consider the more general notion of "partitions" of an nn-valued map, in which a given map is decomposed into a union of other maps which may not be single-valued. We generalize several splitting characterizations which will describe partitions in terms of mixed configuration spaces and mixed braid groups, and connected components of the graph of ff. We demonstrate the ideas with some examples on tori. We also discuss the fixed point theory of nn-valued maps and their partitions, and make some connections to the theory of finite-valued maps due to Crabb.

Keywords

Cite

@article{arxiv.2101.09326,
  title  = {Partitions of $n$-valued maps},
  author = {P. Christopher Staecker},
  journal= {arXiv preprint arXiv:2101.09326},
  year   = {2021}
}
R2 v1 2026-06-23T22:26:18.649Z