English

Compatibility degree of cluster complexes

Rings and Algebras 2021-12-21 v3 Combinatorics Representation Theory

Abstract

We introduce a new function on the set of pairs of cluster variables via ff-vectors, which we call it the compatibility degree (of cluster complexes). The compatibility degree is a natural generalization of the classical compatibility degree introduced by Fomin and Zelevinsky. In particular, we prove that the compatibility degree has the duality property, the symmetry property, the embedding property and the compatibility property, which the classical one has. We also conjecture that the compatibility degree has the exchangeability property. As pieces of evidence of this conjecture, we establish the exchangeability property for cluster algebras of rank 2, acyclic skew-symmetric cluster algebras, cluster algebras arising from weighted projective lines, and cluster algebras arising from marked surfaces.

Keywords

Cite

@article{arxiv.1911.07193,
  title  = {Compatibility degree of cluster complexes},
  author = {Changjian Fu and Yasuaki Gyoda},
  journal= {arXiv preprint arXiv:1911.07193},
  year   = {2021}
}

Comments

37 pages, corrections to some definitions in Section 2.3, other minor corrections, accepted for publication in Annales de l'Institut Fourier

R2 v1 2026-06-23T12:18:16.986Z