[Proof Complexity] New preprint

[Müller, Moritz]

Dear colleagues

There is a new preprint at ArXiv:

https://arxiv.org/abs/2610.15018

Title: Nonstandard combinatorial ultrafilters and a new local witness model

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.

Comments are much appreciated.

Best,

Moritz