Rigidity of length-angle spectrum for closed hyperbolic surfaces

The rigidity of marked length spectrum for closed hyperbolic surfaces due to Fricke-Klein [7] has been the motivation of many different rigidity results, specially for manifolds of negative curvature. From the works of Vigneras [18], Sunada [17] and many other authors this result is far from being true for the unmarked length spectrum. The purpose of this paper is to introduce a closely a related unmarked spectrum, the length-angle spectrum, and show that it determines the surface uniquely.