Dimension vectors of $τ$-rigid modules and $f$-vectors of cluster monomials from triangulated surfaces

Abstract: For the cluster algebra $\mathcal{A}$ associated with a triangulated surface, we give a characterization of the triangulated surface such that different non-initial cluster monomials in $\mathcal{A}$ have different $f$-vectors. Similarly, for the associated Jacobian algebra $J$, we give a characterization of the triangulated surface such that different $\tau$-rigid $J$-modules have different dimension vectors. Moreover, we also show that different basic support $\tau$-tilting $J$-modules have different dimension vectors. Our main ingredient is a notion of intersection numbers defined by Qiu and Zhou. As an application, we show that the denominator conjecture holds for $\mathcal{A}$ if the marked surface is a closed surface with exactly one puncture, or the given tagged triangulation has neither loops nor tagged arcs connecting punctures.