English

On Radon transforms on finite groups

Group Theory 2015-02-05 v2 Differential Geometry Representation Theory

Abstract

If GG is a finite group, is a function f:GCf:G\to\mathbb C determined by its sums over all cosets of cyclic subgroups of GG? In other words, is the Radon transform on GG injective? This inverse problem is a discrete analogue of asking whether a function on a compact Lie group is determined by its integrals over all geodesics. We discuss what makes this new discrete inverse problem analogous to well-studied inverse problems on manifolds and we also present some alternative definitions. We use representation theory to prove that the Radon transform fails to be injective precisely on Frobenius complements. We also give easy-to-check sufficient conditions for injectivity and noninjectivity for the Radon transform, including a complete answer for abelian groups and several examples for nonabelian ones.

Keywords

Cite

@article{arxiv.1411.3829,
  title  = {On Radon transforms on finite groups},
  author = {Joonas Ilmavirta},
  journal= {arXiv preprint arXiv:1411.3829},
  year   = {2015}
}

Comments

23 pages

R2 v1 2026-06-22T06:58:46.055Z