Work

Tight cofinitary groups

Year: 2025

Type: article

Abstract: We introduce the notion of a tight cofinitary group, which captures forcing indestructibility of maximal cofinitary groups for a long list of partial orders, including Cohen, Sacks, Miller, Miller partition forcing and Shelah's poset for diagonalizing maximal ideals. Introducing a new robust coding technique, we establish the relative consistency of a g = d < c = ℵ 2 alongside the existence of a Δ 3 1 -well-order of the reals and a co-analytic witness for a g .

Source: Annals of Pure and Applied Logic

DOI: 10.1016/j.apal.2025.103570

Authors: Vera Fischer, L. Schembecker, David Schrittesser

Institutions: University of Vienna, Universität Hamburg, Harbin Institute of Technology

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: Austrian Science Fund