Punctured groups for exotic fusion systems
Abstract The transporter systems of Oliver and Ventura and the localities of Chermak are classes of algebraic structures that model the p‐local structures of finite groups. Other than the transporter categories and localities of finite groups, important examples include centric, quasicentric, and su...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Wiley
2023-12-01
|
| Series: | Transactions of the London Mathematical Society |
| Online Access: | https://doi.org/10.1112/tlm3.12054 |
| _version_ | 1797394879060377600 |
|---|---|
| author | Ellen Henke Assaf Libman Justin Lynd |
| author_facet | Ellen Henke Assaf Libman Justin Lynd |
| author_sort | Ellen Henke |
| collection | DOAJ |
| description | Abstract The transporter systems of Oliver and Ventura and the localities of Chermak are classes of algebraic structures that model the p‐local structures of finite groups. Other than the transporter categories and localities of finite groups, important examples include centric, quasicentric, and subcentric linking systems for saturated fusion systems. These examples are, however, not defined in general on the full collection of subgroups of the Sylow group. We study here punctured groups, a short name for transporter systems or localities on the collection of nonidentity subgroups of a finite p‐group. As an application of the existence of a punctured group, we show that the subgroup homology decomposition on the centric collection is sharp for the fusion system. We also prove a Signalizer Functor Theorem for punctured groups and use it to show that the smallest Benson–Solomon exotic fusion system at the prime 2 has a punctured group, while the others do not. As for exotic fusion systems at odd primes p, we survey several classes and find that in almost all cases, either the subcentric linking system is a punctured group for the system, or the system has no punctured group because the normalizer of some subgroup of order p is exotic. Finally, we classify punctured groups restricting to the centric linking system for certain fusion systems on extraspecial p‐groups of order p3. |
| first_indexed | 2024-03-09T00:26:09Z |
| format | Article |
| id | doaj.art-401d74a7fa924c95bb3b55894988fe98 |
| institution | Directory Open Access Journal |
| issn | 2052-4986 |
| language | English |
| last_indexed | 2024-03-09T00:26:09Z |
| publishDate | 2023-12-01 |
| publisher | Wiley |
| record_format | Article |
| series | Transactions of the London Mathematical Society |
| spelling | doaj.art-401d74a7fa924c95bb3b55894988fe982023-12-12T02:24:50ZengWileyTransactions of the London Mathematical Society2052-49862023-12-01101219910.1112/tlm3.12054Punctured groups for exotic fusion systemsEllen Henke0Assaf Libman1Justin Lynd2Fakultät Mathematik, TU Dresden Dresden GermanyInstitute of Mathematics King's College, University of Aberdeen Aberdeen UKDepartment of Mathematics University of Louisiana at Lafayette Lafayette Louisiana USAAbstract The transporter systems of Oliver and Ventura and the localities of Chermak are classes of algebraic structures that model the p‐local structures of finite groups. Other than the transporter categories and localities of finite groups, important examples include centric, quasicentric, and subcentric linking systems for saturated fusion systems. These examples are, however, not defined in general on the full collection of subgroups of the Sylow group. We study here punctured groups, a short name for transporter systems or localities on the collection of nonidentity subgroups of a finite p‐group. As an application of the existence of a punctured group, we show that the subgroup homology decomposition on the centric collection is sharp for the fusion system. We also prove a Signalizer Functor Theorem for punctured groups and use it to show that the smallest Benson–Solomon exotic fusion system at the prime 2 has a punctured group, while the others do not. As for exotic fusion systems at odd primes p, we survey several classes and find that in almost all cases, either the subcentric linking system is a punctured group for the system, or the system has no punctured group because the normalizer of some subgroup of order p is exotic. Finally, we classify punctured groups restricting to the centric linking system for certain fusion systems on extraspecial p‐groups of order p3.https://doi.org/10.1112/tlm3.12054 |
| spellingShingle | Ellen Henke Assaf Libman Justin Lynd Punctured groups for exotic fusion systems Transactions of the London Mathematical Society |
| title | Punctured groups for exotic fusion systems |
| title_full | Punctured groups for exotic fusion systems |
| title_fullStr | Punctured groups for exotic fusion systems |
| title_full_unstemmed | Punctured groups for exotic fusion systems |
| title_short | Punctured groups for exotic fusion systems |
| title_sort | punctured groups for exotic fusion systems |
| url | https://doi.org/10.1112/tlm3.12054 |
| work_keys_str_mv | AT ellenhenke puncturedgroupsforexoticfusionsystems AT assaflibman puncturedgroupsforexoticfusionsystems AT justinlynd puncturedgroupsforexoticfusionsystems |