Benson's conjecture on tensor products of odd-dimensional representations

Let GG) be a finite 22-group, let k\Bbbk be a field of characteristic 22, and let VV be an odd-dimensional representation of GG. An indecomposable representation is called a 22'-representation when its dimension is not divisible by 22, and it is called 22'-invertible when its tensor product with its dual decomposes as the direct sum of the trivial representation and representations whose dimensions are divisible by 22.

Benson's conjecture. All indecomposable summands of VVV\otimes V^* have dimension divisible by 22, except for the single summand isomorphic to the trivial representation k\Bbbk; equivalently, every 22'-representation is 22'-invertible.

This conjecture is attributed to Dave Benson and is based on extensive computer-algebra evidence. The paper notes a stronger version in which all nontrivial summands have dimension divisible by 44, but the supplied text does not state its resolution.

Sources & referencesView supporting material

Primary source

Kent B. Vashaw and Justin Zhang, “Non-negligible summands in tensor powers of some modular representations of finite p-groups”, arXiv:2508.15730 (2026).

Additional references

4 papers in this index state this conjecture (2021–2025). The statement above is taken from the most recent of them; the others are arXiv:2301.04274, arXiv:2107.02372, arXiv:2103.04878.

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.