English

Prescribed duality dynamics in comodule categories

Rings and Algebras 2024-08-16 v1 Combinatorics Category Theory Quantum Algebra

Abstract

We prove that there exist Hopf algebras with surjective, non-bijective antipode which admit no non-trivial morphisms from Hopf algebras with bijective antipode; in particular, they are not quotients of such. This answers a question left open in prior work, and contrasts with the dual setup whereby a Hopf algebra has injective antipode precisely when it embeds into one with bijective antipode. The examples rely on the broader phenomenon of realizing pre-specified subspace lattices as comodule lattices: for a finite-dimensional vector space VV and a sequence (Lr)r(\mathcal{L}_r)_r of successively finer lattices of subspaces thereof, assuming the minimal subquotients of the supremum rLr\bigvee_r \mathcal{L}_r are all at least 2-dimensional, there is a Hopf algebra equipping VV with a comodule structure in such a fashion that the lattice of comodules of the rthr^{th} dual comodule VrV^{r*} is precisely the given Lr\mathcal{L}_r.

Keywords

Cite

@article{arxiv.2408.08167,
  title  = {Prescribed duality dynamics in comodule categories},
  author = {Alexandru Chirvasitu},
  journal= {arXiv preprint arXiv:2408.08167},
  year   = {2024}
}

Comments

13 pages + references

R2 v1 2026-06-28T18:13:48.708Z