English

$K$-Bad Spheres

Algebraic Topology 2026-01-07 v1

Abstract

In this paper we look at the EE-completion of topological spaces where EE is a pp-local ring spectrum. After a brief review of the concept of EE-completion, we specialize to the case where E=KE=K, pp-local complex periodic KK-theory, and consider the KK-theory of the unstable sphere S2n+1S^{2n+1}. We show that for certain values of nn and an odd prime pp, the KK-homology of the KK-completion is not isomorphic to the KK-homology of the sphere itself, thus in the terminology of Bousfield and Kan, these spheres are 'KK-bad'.

Keywords

Cite

@article{arxiv.2601.02620,
  title  = {$K$-Bad Spheres},
  author = {Martin Bendersky and Robert Thompson},
  journal= {arXiv preprint arXiv:2601.02620},
  year   = {2026}
}

Comments

14 pages

R2 v1 2026-07-01T08:51:54.720Z