Nonvanishing Higher Derived Limits without $w\diamondsuit_{\omega_1}$
Logic
2025-08-04 v2
Abstract
We prove a common refinement of theorems of Bergfalk and of Casarosa and Lambie-Hanson, showing that under certain hypotheses, the higher derived limits of a certain inverse system of abelian groups do not vanish. The refined theorem has a number of interesting corollaries, including the nonvanishing of the second derived limit of in many of the common models of set theory of the reals and in the Mitchell model. In particular, we disprove a conjecture of Bergfalk, Hru\v{s}\'ak, and Lambie-Hanson that higher derived limits of vanish in the Miller model.
Cite
@article{arxiv.2506.14183,
title = {Nonvanishing Higher Derived Limits without $w\diamondsuit_{\omega_1}$},
author = {Nathaniel Bannister},
journal= {arXiv preprint arXiv:2506.14183},
year = {2025}
}
Comments
16 pages