English

Earthquake theorem for cluster algebras of finite type

Geometric Topology 2024-12-16 v5 Combinatorics

Abstract

We introduce a cluster algebraic generalization of Thurston's earthquake map for the cluster algebras of finite type, which we call the \emph{cluster earthquake map}. It is defined by gluing exponential maps, which is modeled after the earthquakes along ideal arcs. We prove an analogue of the earthquake theorem, which states that the cluster earthquake map gives a homeomorphism between the spaces of Rtrop\mathbb{R}^\mathrm{trop}- and R>0\mathbb{R}_{>0}-valued points of the cluster X\mathcal{X}-variety. For those of type AnA_n and DnD_n, the cluster earthquake map indeed recovers the earthquake maps for marked disks and once-punctured marked disks, respectively. Moreover, we investigate certain asymptotic behaviors of the cluster earthquake map, which give rise to "continuous deformations" of the Fock--Goncharov fan.

Keywords

Cite

@article{arxiv.2206.15226,
  title  = {Earthquake theorem for cluster algebras of finite type},
  author = {Takeru Asaka and Tsukasa Ishibashi and Shunsuke Kano},
  journal= {arXiv preprint arXiv:2206.15226},
  year   = {2024}
}

Comments

38 pages, 9 figures. We modified the topological condition for marked surfaces in Appendix A and the definition of the earthquake map in Appendix B from the journal version