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arXiv · 2610.15018

Nonstandard combinatorial ultrafilters and a new local witness model

Johannes Heil·Moritz Müller
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Abstract

A central object in the theory of proof complexity generators is Krajicek's local witness model. We construct a new such model as a definable ultrapower using a definable version of a selective ultrafilter over a model of arithmetic. We transfer some set theory of combinatorial ultrafilters to the definable nonstandard setting.

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Johannes Heil, Moritz Müller. 2026-10-10. Nonstandard combinatorial ultrafilters and a new local witness model. https://arxiv.org/abs/2610.15018

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