Linear independence of coherent systems associated to lattices
This note considers the finite linear independence of coherent systems. We show by simple arguments that lattice coherent systems of amenable groups are linearly independent whenever the associated twisted group ring does not contain any nontrivial zero divisors. We verify the latter for discrete locally indicable groups, which includes lattices in nilpotent Lie groups. For the particular case of time-frequency translates of Euclidean space, our main result recovers the Heil-Ramanathan-Topiwala (HRT) conjecture for subsets of arbitrary lattices.