Skip to Main Content

Representation Theory

Published by the American Mathematical Society since 1997, this electronic-only journal is devoted to research in representation theory and seeks to maintain a high standard for exposition as well as for mathematical content. All articles are freely available to all readers and with no publishing fees for authors.

ISSN 1088-4165

The 2020 MCQ for Representation Theory is 0.71.

What is MCQ? The Mathematical Citation Quotient (MCQ) measures journal impact by looking at citations over a five-year period. Subscribers to MathSciNet may click through for more detailed information.


Simple and projective correspondence functors
HTML articles powered by AMS MathViewer

by Serge Bouc and Jacques Thévenaz
Represent. Theory 25 (2021), 224-264
Published electronically: April 2, 2021


A correspondence functor is a functor from the category of finite sets and correspondences to the category of $k$-modules, where $k$ is a commutative ring. We determine exactly which simple correspondence functors are projective. We also determine which simple modules are projective for the algebra of all relations on a finite set. Moreover, we analyze the occurrence of such simple projective functors inside the correspondence functor $F$ associated with a finite lattice and we deduce a direct sum decomposition of $F$.
Similar Articles
Bibliographic Information
  • Serge Bouc
  • Affiliation: CNRS-LAMFA, Université de Picardie - Jules Verne, 33, rue St Leu, F-80039 Amiens Cedex 1, France
  • MR Author ID: 207609
  • ORCID: 0000-0003-2330-1845
  • Email:
  • Jacques Thévenaz
  • Affiliation: Institut de mathématiques, EPFL, Station 8, CH-1015 Lausanne, Switzerland
  • ORCID: 0000-0001-8820-3627
  • Email:
  • Received by editor(s): September 7, 2020
  • Received by editor(s) in revised form: January 12, 2021
  • Published electronically: April 2, 2021
  • © Copyright 2021 American Mathematical Society
  • Journal: Represent. Theory 25 (2021), 224-264
  • MSC (2020): Primary 06B05, 06B15, 06D05, 06D50, 16B50, 18B05, 18B10, 18B35, 18E05
  • DOI:
  • MathSciNet review: 4238629