{"title":"组合范畴中的规定对偶动力学","authors":"Alexandru Chirvasitu","doi":"arxiv-2408.08167","DOIUrl":null,"url":null,"abstract":"We prove that there exist Hopf algebras with surjective, non-bijective\nantipode which admit no non-trivial morphisms from Hopf algebras with bijective\nantipode; in particular, they are not quotients of such. This answers a\nquestion left open in prior work, and contrasts with the dual setup whereby a\nHopf algebra has injective antipode precisely when it embeds into one with\nbijective antipode. The examples rely on the broader phenomenon of realizing\npre-specified subspace lattices as comodule lattices: for a finite-dimensional\nvector space $V$ and a sequence $(\\mathcal{L}_r)_r$ of successively finer\nlattices of subspaces thereof, assuming the minimal subquotients of the\nsupremum $\\bigvee_r \\mathcal{L}_r$ are all at least 2-dimensional, there is a\nHopf algebra equipping $V$ with a comodule structure in such a fashion that the\nlattice of comodules of the $r^{th}$ dual comodule $V^{r*}$ is precisely the\ngiven $\\mathcal{L}_r$.","PeriodicalId":501135,"journal":{"name":"arXiv - MATH - Category Theory","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Prescribed duality dynamics in comodule categories\",\"authors\":\"Alexandru Chirvasitu\",\"doi\":\"arxiv-2408.08167\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"We prove that there exist Hopf algebras with surjective, non-bijective\\nantipode which admit no non-trivial morphisms from Hopf algebras with bijective\\nantipode; in particular, they are not quotients of such. This answers a\\nquestion left open in prior work, and contrasts with the dual setup whereby a\\nHopf algebra has injective antipode precisely when it embeds into one with\\nbijective antipode. The examples rely on the broader phenomenon of realizing\\npre-specified subspace lattices as comodule lattices: for a finite-dimensional\\nvector space $V$ and a sequence $(\\\\mathcal{L}_r)_r$ of successively finer\\nlattices of subspaces thereof, assuming the minimal subquotients of the\\nsupremum $\\\\bigvee_r \\\\mathcal{L}_r$ are all at least 2-dimensional, there is a\\nHopf algebra equipping $V$ with a comodule structure in such a fashion that the\\nlattice of comodules of the $r^{th}$ dual comodule $V^{r*}$ is precisely the\\ngiven $\\\\mathcal{L}_r$.\",\"PeriodicalId\":501135,\"journal\":{\"name\":\"arXiv - MATH - Category Theory\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2024-08-15\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"arXiv - MATH - Category Theory\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/arxiv-2408.08167\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"arXiv - MATH - Category Theory","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/arxiv-2408.08167","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Prescribed duality dynamics in comodule categories
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 $V$ and a sequence $(\mathcal{L}_r)_r$ of successively finer
lattices of subspaces thereof, assuming the minimal subquotients of the
supremum $\bigvee_r \mathcal{L}_r$ are all at least 2-dimensional, there is a
Hopf algebra equipping $V$ with a comodule structure in such a fashion that the
lattice of comodules of the $r^{th}$ dual comodule $V^{r*}$ is precisely the
given $\mathcal{L}_r$.