English

Higher limits of wider systems

Logic 2025-07-09 v1 K-Theory and Homology

Abstract

Write Aλ\mathbf{A}_\lambda for what might be described as the most elementary nontrivial inverse system of abelian groups indexed by the functions from the cardinal λ\lambda to the set of natural numbers. The question of whether for any fixed nn the derived limit limnAλ\mathrm{lim}^n\,\mathbf{A}_\lambda may vanish for only a nonempty subset of the class of infinite cardinals λ\lambda is recorded in both [Be17] and [Ban23], and bears closely on several related further ones. We answer this question in the affirmative; in fact, we show the maximal possibility, namely that this can simultaneously happen in every degree n>1n>1.

Keywords

Cite

@article{arxiv.2507.05471,
  title  = {Higher limits of wider systems},
  author = {Jeffrey Bergfalk and Matteo Casarosa},
  journal= {arXiv preprint arXiv:2507.05471},
  year   = {2025}
}

Comments

25 pages; comments welcome

R2 v1 2026-07-01T03:50:24.434Z