Triangulated monoidal categorifications of finite type cluster algebras
Élie Casbi
TL;DR
This work develops a triangulated, monoidal categorification framework for finite type cluster algebras by constructing the bounded homotopy category $\mathcal{K}_Q^{(1)}$ from the ambient monoidal category $\mathcal{H}_Q^{(1)}$ tied to a Dynkin quiver $Q$. It introduces a systematic, iterated mapping-cone procedure that yields chain complexes $C_{\bullet}[\beta]$ whose distinguished triangles categorify exchange relations, and proves that their Euler characteristics realize the truncated $q$-characters of simple HL modules, thereby connecting AR-theoretic data to cluster variables. A uniform dominant-monomial formula is established for types $A_n$ and $D_n$, and the construction is positioned to extend to broader cluster structures beyond finite type, illuminating links to higher homological algebra and the broader landscape of monoidal categorifications. The results provide a conceptual bridge between Auslander-Reiten theory, quantum affine representation theory, and cluster algebra combinatorics, with potential implications for interpreting $q$-character coefficients and for developing triangulated categorifications in tame or wild types.
Abstract
We propose a framework of monoidal categorification of finite type cluster algebras involving triangulated monoidal categories. Namely, given a Dynkin quiver $Q$, we consider the bounded homotopy category $\mathcal{K}_Q^{(1)}$ of a symmetric monoidal category $\mathcal{H}_Q^{(1)}$ that we define in terms of the Auslander-Reiten theory of $Q$. Using some iterated mapping cone procedure, we construct a distinguished family $\{ C_{\bullet}[β] \}_{β\in Δ_+}$ of chain complexes in $\mathcal{K}_Q^{(1)}$ characterized (up to isomorphism) by homological conditions similar to those of higher exact sequences appearing in the context of higher homological algebra. We then prove that the distinguished triangle in $\mathcal{K}_Q^{(1)}$ given by each mapping cone categorifies an exchange relation in the finite type cluster algebra $\mathcal{A}_Q$ with initial exchange quiver $Q$ (for a suitable choice of frozen variables). As a consequence, we obtain that for each positive root $β$, the Euler characteristic of $C_{\bullet}[β]$ coincides with the truncated $q$-character of the simple module $L[β]$ in the HL category $\mathcal{C}_ξ^{(1)}$ categorifying the cluster variable $x[β]$ of $\mathcal{A}_Q$ via Hernandez-Leclerc's monoidal categorification. Along the way, we establish a uniform formula for the dominant monomial of $L[β]$ in all types $A_n$ and $D_n$ for arbitrary orientations (agreeing with Brito-Chari's results in type $A_n$).
