The approach of cluster symmetry to Diophantine equations
Leizhen Bao, Fang Li
TL;DR
The paper develops a systematic framework that ties cluster theory to Diophantine equations by introducing cluster-symmetric maps and invariant Laurent polynomials, enabling solution generation via mutations.A central technical contribution is a necessary-and-sufficient criterion (via homogeneous linear equations) for a Laurent polynomial to be invariant under a cluster-symmetric map, together with computational tools to construct such invariants.The authors apply the framework to Markov-type equations, proving that several Markov-cluster polynomials share the same orbit structure as the classical Markov equation and providing explicit seeds and mutations for rank-3 cases like $F_{3,10}$ and $F_{3,7}$, thereby solving corresponding Diophantine problems.Additionally, the work clarifies when a Laurent polynomial can be realized within a generalized cluster algebra, develops algorithms to identify cluster-symmetric pairs, and outlines a practical workflow for constructing invariant rings and associated Diophantine equations, highlighting applications and connections across cluster theory, invariant theory, and number theory.
Abstract
This paper aims to employ a cluster-theoretic approach to provide a class of Diophantine equations whose solutions can be obtained by starting from initial solutions through mutations. We establish a novel framework bridging cluster theory and Diophantine equations through the lens of cluster symmetry. On the one hand, we give the necessary and sufficient condition for Laurent polynomials to remain invariant under a given cluster symmetric map. On the other hand, we construct a discriminant algorithm to determine whether a given Laurent polynomial has cluster symmetry and whether it can be realized in a generalized cluster algebra. As applications, we solve Markov-cluster equations, describe some invariant Laurent polynomial rings, and resolve the questions posed by Gyoda and Matsushita.
