“…A very popular source of spd systems is the discrete Laplace-Beltrami operator ∆ S [30], which is closely related to frequencies of scalar fields defined on a two-manifold surface S [41]. This operator has various applications in surface smoothing [13,41], surface parameterization [32,12], variational surface modeling [25,7,38,44], mesh morphing [3,4,43], and shape analysis [31]. Besides from surfaces, the standard Laplace operator is for instance also used in image editing [40] and fluid simulation [39].…”