Let A be a gentle algebra. It is given by a quiver (directed graph) and 0-relations (non-admissible directed paths). The indecomposable modules of A are determined by the combinatorics of undirected walks on the quiver. So every module admits a
In 1966, Mark Kac famously asked: “Can one hear the shape of a drum?” — that is, can the geometry of a domain $\Omega \in \RR^d$ be determined from the spectrum of the Dirichlet Laplacian on $\Omega$? The answer, known