“…Negatively curved spaces have also recently been considered in the context of statistical physics and condensed matter theory. There, the motivations are both practical (describing the behavior of newly designed mesoscopic and nanoscopic objects with exotic shapes, curvatures, and topological properties [10,11,12,13,14,15]) and theoretical (understanding how curvature influences the critical behavior and the phase transitions of classical statistical systems [5,8,16,17,18,19,20,21,22,23,24,25,26,27,28,29]). Still in condensed-matter theory, negatively curved spaces appear in studies of the Quantum Hall effect [10,11,12] and in the framework of "geometrical frustration" [30,31,32].…”