The periodicity conjecture for pairs of Dynkin diagrams
Bernhard Keller
TL;DR
The paper proves the periodicity conjecture for Y-systems associated with pairs of Dynkin diagrams by reframing the problem in the language of cluster algebras and their 2-Calabi-Yau categorifications. It constructs a 2-CY realization from the triangle product of quivers, uses Zamolodchikov transformations to encode the dynamics, and shows that the induced autoequivalence has finite order dividing $h+h'$, thereby giving a uniform, effective proof of periodicity. The approach also yields an explicit, categorically flavored path to the general solution of the Y-system via homological invariants and quiver Grassmannians. The non simply-laced case is handled via folding, reducing to the simply-laced proof, with the overall result providing a conceptual, and in principle computationally explicit, understanding of Y-system periodicity in this broad setting.
Abstract
We prove the periodicity conjecture for pairs of Dynkin diagrams using Fomin-Zelevinsky's cluster algebras and their (additive) categorification via triangulated categories.
