English

Combinatorics of faithfully balanced modules

Representation Theory 2019-09-09 v2 Combinatorics

Abstract

We study and classify faithfully balanced modules for the algebra of lower triangular nn by nn matrices. The theory extends known results about tilting modules, which are classified by binary trees, and counted with the Catalan numbers. The number of faithfully balanced modules is a 22-factorial number. Among them are n!n! modules with nn indecomposable summands, which can be classified by interleaved binary trees or by increasing binary trees.

Keywords

Cite

@article{arxiv.1905.00613,
  title  = {Combinatorics of faithfully balanced modules},
  author = {William Crawley-Boevey and Biao Ma and Baptiste Rognerud and Julia Sauter},
  journal= {arXiv preprint arXiv:1905.00613},
  year   = {2019}
}

Comments

28 pages, 5 figures

R2 v1 2026-06-23T08:54:55.782Z