2 papers
math.AT2026
Swan modules and homotopy types after a single stabilisation
Tommy Hofmann, John Nicholson
We study Swan modules, which are a special class of projective modules over integral group rings, and their consequences for the homotopy classification of CW-complexes. We show th…
math.GR2025
Exotic presentations of quaternion groups and Wall's D2 problem
Tommy Hofmann, John Nicholson
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 h…