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The distance from self-intersection of a (smooth and either closed or infinite) curve q in three dimensions can be characterised via the global radius of curvature at q(s), which is defined as the smallest possible radius amongst all circles passing throug ...
We announce results on the structure of CAT(0) groups, CAT(0) lattices and of the underlying spaces. Our statements rely notably on a general study of the full isometry groups of proper CAT(0) spaces. Classical statements about Hadamard manifolds are estab ...
In this paper we define a scale-space for cortical mean curvature maps on the sphere, that offers a hierarchical representation of the cortical structures, useful in multi-scale algorithms. A spherical feature map is obtained through inflation of the corti ...
This paper contains a new asymptotic formula relating the mean curvature of a hypersurface at a given point and the volume of small balls centered at this point. ...
We establish an arithmeticity vs. non-linearity alternative for irreducible lattices in suitable product groups, such as for instance products of topologically simple groups. This applies notably to (a large class of) Kac–Moody groups. The alternative reli ...
We introduce new techniques to extend superrigidity theory beyond the scope of Lie or algebraic groups. We construct a cohomological invariant which accounts for, and generalizes, all known superrigidity results for actions on negatively curved spaces. Tog ...
A microfabrication process of a multifunctional probe is introduced for atomic force microscopy and various electrochemical measurements on biological samples in buffer solution. The silicon nitride probes have a spring constant lower than 0.1 N/m and a co ...
In the present paper, we study the spatialization of the soundfield in a room, in particular the evolution of room impulse responses as function of their spatial positions. The presented technique allows us to completely characterize the sound field in any ...
Introducing a microscope objective in an interferometric setup induces a phase curvature on the resulting wavefront. In digital holography, the compensation of this curvature is often done by introducing an identical curvature in the reference arm and the ...
We prove general superrigidity results for actions of irreducible lattices on CAT(0) spaces; first, in terms of the ideal boundary, and then for the intrinsic geometry (including for infinite-dimensional spaces). In particular, one obtains a new and self-c ...