$\tau$-exceptional sequences

Abstract

We introduce the notions of $\tau$-exceptional and signed $\tau$-exceptional sequences for any finite dimensional algebra. We prove that for a fixed algebra of rank $n$, and for any positive integer $t\le n$, there is a bijection between the set of signed $\tau$-exceptional sequences of length $t$, and (basic) ordered support $\tau$-rigid objects with $t$ indecomposable direct summands. If the algebra is hereditary, our notions coincide with exceptional and signed exceptional sequences. The latter were recently introduced by Igusa and Todorov, who constructed a similar bijection in the hereditary setting.

28 pages. To appear in the Journal of Algebra