Exotic presentations of quaternion groups and Wall's D2 problem
Abstract
The D2 problem of C. T. C. Wall asks whether every finite cohomologically 2-dimensional CW-complex is homotopy equivalent to a finite 2-complex. Several potential counterexamples have been proposed, the longest standing of which is a CW-complex constructed by Cohen and Dyer whose fundamental group is a quaternion group of order 32. We show that this CW-complex is homotopy equivalent to the presentation 2-complex of a presentation constructed by Mannan-Popiel, thus showing it is not a counterexample to the D2 problem. We next introduce an infinite family of presentations for a quaternion group of order $4n$ and prove that they achieve homotopy types which are not achieved by the presentations of Mannan-Popiel.
Fields of Study & Subjects
Algebraic and Geometric Analysis
Mathematics and Applications
Advanced Mathematical Theories and Applications
Publication details
- Journal / source
- Journal of Algebra
- Volume
- 712
- Pages
- 253–310
- Publication date
- 16 July 2026
- Language
- EN