One long-established simplifying principle behind the large repertoire and high versatility of human hand movements is the two-thirds power law-an empirical law stating a relationship between local geometry and kinematics of human hand trajectories during planar curved movements. It was further generalized not only to various types of human movements, but also to motion perception and predictio...

In the recent literature on the dynamics of the distribution of wealth in the U.S. two empirical results have received considerable attention. First, that wealth is distributed according to a power law distribution at high wealth levels. Second, that wealth inequality has intensified over the past two decades (Weicher, 1997; Wolff, 1998; Rodriguez et al., 2002). Notwithstanding the focus on the...

One of the interesting properties of curved hand movements is that the speed v is related to the curvature k through a power law: v(t) ∝ k(t)-1/3 , called the ⅔ power law (because the angular speed is proportional to k 2/3). Several models have been proposed to explain the origin of the ⅔ power law from optimality principle: the minimum jerk models to name a few. It seemed the ⅔ power law was a...