Work

Maximal sets without choice

Year: 2025

Type: article

Abstract: We show that it is consistent relative to ZF , that there is no well-ordering of R while a wide class of special sets of reals such as Hamel bases, transcendence bases, Vitali sets or Bernstein sets exists. To be more precise, we can assume that every projective hypergraph on R has a maximal independent set, among a few other things. For example, we get transversals for all projective equivalence relations. Moreover, this is possible while either DC ω 1 holds, or countable choice for reals fails. Assuming the consistency of an inaccessible cardinal, “projective” can even be replaced with “ L ( R ) ” and we can add that any instance of AC in L ( R ) has a choice function. This vastly strengthens the consistency results obtained in [6] , [11] or [15] .

Source: Annals of Pure and Applied Logic

DOI: 10.1016/j.apal.2025.103694

Author: Jonathan Schilhan

Institution: University of Vienna

Language: English

Topic: Advanced Topology and Set Theory

Subfield: Geometry and Topology

Field: Mathematics

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,520

Funder: UK Research and Innovation