We consider an ion whose motion is con®ned to a plane perpendicular to a constant magnetic ®eld. A harmonic trapping ®eld is applied within the plane of the ion’s motion, together with some unspeci®ed irradiating probe beam. By determining the dynamics of the ion we show that the particle theory is formally equivalent to that of a coupled massive ...1‡ 2†-dimensional vector Boson ®eld. The ®eld...

Let $K$ be a locally compact hypergroup with left Haar measure and let $L^1(K)$ be the complex Lebesgue space associated with it. Let $L^infty(K)$ be the dual of $L^1(K)$. The purpose of this paper is to present some necessary and sufficient conditions for $L^infty(K)^*$ to have a topologically left invariant mean. Some characterizations of amenable hypergroups are given.

We show that under equilibrium conditions, an anisotropic phase-eld model of a diiuse interface leads to the notion of a divergence-free tensor, whose components are negligible away from the interface. Near the interface, it plays the r^ ole of a stress tensor, and involves the phase-eld generalisation of the Cahn-Hooman-vector. We show that this tensor may be used to derive the equilibrium con...

NOAA/AVHRR infrared satellite imagery is well suited to the study of mesoscale dynamic structures such as vortices or temperatures fronts. Since data are delivered on a daily basis, the problem of model-ing structures in these images is an important matter. We use the spline vector eld technique to compute a dense vector eld on an image such that speciic orbits of the eld correspond to the boun...

We examine the problem of estimating a reverse motion vector eld from a given forward motion vector eld and its motion-compensated residual. This problem has practical importance when providing reverse-play function-ality in compressed video environments, where video data is stored, processed, and transported in compressed form. We present a family of algorithms that trade oo motion vector accu...

The view lines associated with a family of proole curves of the projection of a surface onto the retina of a moving camera deenes a multi-valued vector eld on the surface. The integral curves of this eld are called epipolar curves and together with a parametrization of the prooles provide a parametrization of regions of the surface. This parametrization has been used in the systematic reconstru...

While graphical visualization has advanced our ability to understand large multi-dimensional data sets, some types of data are still diicult to convey visually. Combined visual/haptic computer interfaces may allow users to explore multi-dimensional data sets more naturally, where the human haptic sense involving touch, limb position, and muscle tension provides a complementary information chann...

The representations of dimension vector α of the quiver Q can be parametrised by a vector space R(Q,α) on which an algebraic group Gl(α) acts so that the set of orbits is bijective with the set of isomorphism classes of representations of the quiver. We describe the semi–invariant polynomial functions on this vector space in terms of the category of representations. More precisely, we associate...