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Ehresmann theory and partition monoids.
- Source :
-
Journal of Algebra . Aug2021, Vol. 579, p318-352. 35p. - Publication Year :
- 2021
-
Abstract
- This article concerns Ehresmann structures in the partition monoid P X. Since P X contains the symmetric and dual symmetric inverse monoids on the same base set X , it naturally contains the semilattices of idempotents of both submonoids. We show that one of these semilattices leads to an Ehresmann structure on P X while the other does not. We explore some consequences of this (structural/combinatorial and representation theoretic), and in particular characterise the largest left-, right- and two-sided restriction submonoids. The new results are contrasted with known results concerning relation monoids, and a number of interesting dualities arise, stemming from the traditional philosophies of inverse semigroups as models of partial symmetries (Vagner and Preston) or block symmetries (FitzGerald and Leech): "surjections between subsets" for relations become "injections between quotients" for partitions. We also consider some related diagram monoids, including rook partition monoids, and state several open problems. [ABSTRACT FROM AUTHOR]
- Subjects :
- *MONOIDS
*PARTITIONS (Mathematics)
*IDEMPOTENTS
*SURJECTIONS
*LEECHES
*SEMILATTICES
Subjects
Details
- Language :
- English
- ISSN :
- 00218693
- Volume :
- 579
- Database :
- Academic Search Index
- Journal :
- Journal of Algebra
- Publication Type :
- Academic Journal
- Accession number :
- 149886872
- Full Text :
- https://doi.org/10.1016/j.jalgebra.2021.02.038