Prescribed duality dynamics in comodule categories
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 and a sequence of successively finer lattices of subspaces thereof, assuming the minimal subquotients of the supremum are all at least 2-dimensional, there is a Hopf algebra equipping with a comodule structure in such a fashion that the lattice of comodules of the dual comodule is precisely the given .
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