From m-clusters to m-noncrossing partitions via exceptional sequences

Abstract: Let W be a finite crystallographic reflection group. The generalized Catalan number of W coincides both with the number of clusters in the cluster algebra associated to W, and with the number of noncrossing partitions for W. Natural bijections between these two sets are known. For any positive integer m, both m-clusters and m-noncrossing partitions have been defined, and the cardinality of both these sets is the Fuss-Catalan number. We give a natural bijection between these two sets by first establishing a bijection between two particular sets of exceptional sequences in the bounded derived category for any finite-dimensional hereditary algebra.