Work

Distinguishing internally club and approachable on an Infinite interval

Year: 2025

Type: article

Abstract: Krueger showed that implies that for all regular , there are stationarily many that are internally club but not internally approachable. From countably many Mahlo cardinals, we force a model in which, for all positive and , there is a stationary subset of consisting of sets that are internally club but not internally approachable. The theorem is obtained using a new variant of Mitchell forcing. This answers questions of Krueger.

Source: Bulletin of the London Mathematical Society

DOI: 10.1112/blms.70013

Authors: Hannes Jakob, Maxwell Levine

Institution: University of Freiburg

Language: English

Topic: Advanced Topology and Set Theory

Subfield: Geometry and Topology

Field: Mathematics

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,930

OpenAlex ID: W4407826214

FWCI:

Cites: 11

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Related to: 10