## Abstract

We generalise surface cluster algebras to the case of infinite surfaces where the surface contains finitely many accumulation points of boundary marked points. To connect different triangulations of an infinite surface, we consider infinite mutation sequences. We show transitivity of infinite mutation sequences on triangulations of an infinite surface and examine different types of mutation sequences. Moreover, we use a hyperbolic structure on an infinite surface to extend the notion of surface cluster algebras to infinite rank by giving cluster variables as lambda lengths of arcs. Furthermore, we study the structural properties of infinite rank surface cluster algebras in combinatorial terms, namely we extend “snake graph combinatorics” to give an expansion formula for cluster variables. We also show skein relations for infinite rank surface cluster algebras.

Original language | English |
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Pages (from-to) | 862-942 |

Number of pages | 81 |

Journal | Advances in Mathematics |

Volume | 352 |

DOIs | |

Publication status | Published - 20 Aug 2019 |

Externally published | Yes |

### Funding

This work was partially supported by EPSRC grant EP/N005457/1.☆ This work was partially supported by EPSRC grant EP/N005457/1.

Funders | Funder number |
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Engineering and Physical Sciences Research Council | EP/N005457/1 |

## Keywords

- Decorated Teichmüller space
- Infinite sequence of mutations
- Infinite triangulation
- Lambda length
- Skein relation
- Surface cluster algebra