Broken lines and compatible pairs for rank 2 quantum cluster algebras
摘要
There have been several combinatorial constructions of universally positive bases in cluster algebras, and these same combinatorial objects play a crucial role in the known proofs of the famous positivity conjecture for cluster algebras. The greedy basis was constructed in rank 2 by Lee–Li–Zelevinsky using compatible pairs on Dyck paths. The theta basis, introduced by Gross–Hacking–Keel–Kontsevich, has elements expressed as a sum over broken lines on scattering diagrams. It was shown by Cheung–Gross–Muller–Musiker–Rupel–Stella–Williams that these bases coincide in rank 2 via algebraic methods, and they posed the open problem of giving a combinatorial proof by constructing a (weighted) bijection between compatible pairs and broken lines. We construct a quantum-weighted bijection between compatible pairs and broken lines for the quantum type