Questions related to cluster algebras, a class of commutative rings introduced around 2000 by Fomin and Zelevinsky, and nearby topics.

Cluster algebras were introduced by Fomin and Zelevinsky in a series of papers, the first of which appeared in 2002. A cluster algebra is a commutative algebra, generated by a (typically infinite) set of elements, called "cluster variables", which are grouped into overlapping sets, called "clusters", of a fixed size, which is called the "rank" of the cluster algebra.

There is a fairly wide list of topics related to cluster algebras, including:

- total positivity in algebraic groups
- canonical bases in homogeneous co-ordinate rings of homogeneous varieties
- Poisson geometry
- Teichmüller theory
- representation theory of finite-dimensional algebras
- combinatorics of Coxeter groups
- Donaldson-Thomas theory
- the Thermodynamic Bethe Ansatz

There are also non-commutative versions of cluster algebras, called quantum cluster algebras.

A number of excellent surveys on cluster algebras have been written. Here are links to the ICM 2010 talks by Sergey Fomin and Bernard Leclerc.