In this paper we analyze energy functionals concentrated on the discontinuity lines of unitlength, divergence-free 2D vector fields. The motivation comes from thin-film micromagnetics where these functionals correspond to mesoscopic wall-energies. A natural issue consists in characterizing the line-energy densities for which the functionals are lower semicontinuous for a relevant topology. In f...

The Hypercontractive Inequality of Bonami (1968, 1970) and Gross (1975) is equivalent to the following statement: for every q > 2 and every function f : {−1,1}n→ R of Fourier degree at most m, ‖ f‖q ≤ (q−1)m/2‖ f‖2 . The original proof of this inequality is analytical. Friedgut and Rödl (2001) gave an alternative proof of the slightly weaker Hypercontractive Inequality ‖ f‖4 ≤ 28m/4‖ f‖2 by com...

We study the variations in two dimensional (2D) pointing tasks on a traditional white board of a group of subjects by means of capturing their movement traces in an automatic way with the Mimio device. Such traces provide detailed insight in the variability of 2D pointing relevant for example for the design of computer vision based gestural interaction. This study provides experimental evidence...