Framed configuration spaces and exotic spheres
Algebraic Topology
2026-05-20 v2 Geometric Topology
Abstract
We determine when an exotic sphere of dimension can be detected through the homotopy type of its truncated Disc-presheaf. The latter records the diagram of framed configuration spaces of bounded cardinality in with natural point-forgetting and -splitting maps between them, and it gives rise to the finite stages in Goodwillie--Weiss' embedding calculus tower. Our proof involves three ingredients that could be of independent interest: a gluing result for Disc-presheaves of manifolds divided into two codimension zero submanifolds, a version of Atiyah duality in the context ofDisc-presheaves, and a computation of the finite residual of the mapping class group of the connected sums .
Cite
@article{arxiv.2509.19074,
title = {Framed configuration spaces and exotic spheres},
author = {Manuel Krannich and Alexander Kupers and Fadi Mezher},
journal= {arXiv preprint arXiv:2509.19074},
year = {2026}
}
Comments
28 pages, 1 figure, to appear in Forum of Mathematics Sigma