We introduce a family of conditions on a simplicial complex that we call local klargeness (k ≥ 6 is an integer). They are simply stated, combinatorial and easily checkable. One of our themes is that local 6-largeness is a good analogue of the nonpositive curvature: locally 6-large spaces have many properties similar to nonpositively curved ones. However, local 6-largeness neither implies nor is...

This paper shows that the continuous shearlet transform, a novel directional multiscale transform recently introduced by the authors and their collaborators, provides a precise geometrical characterization for the boundary curves of very general planar regions. This study is motivated by imaging applications, where such boundary curves represent edges of images. The shearlet approach is able to...

Given the Finsler structure (M, F) on a manifold M, a Riemannian structure (M, h) and a linear connection on M are defined. They are obtained as the " average " of the Finsler structure and the Chern connection. This linear connection is the Levi-Civita connection of the Riemannian metric h. The relation between parallel transport of the Chern connection and the Levi-Civita connection of h are ...

condition of contour lines in topographic maps, explains more geomorphologic issues such as effective processes in the land forms found in nature. change in the curvature of the transverse profile of a valley in mountainous areas, the peak of the mountain range, also reflect the geomorphologic features and expresses the tectonic events and climate changes occurring in the region. these changes ...

We show, using purely classical considerations and logical extrapolation of results belonging to point particle theories, that the metric background field in which a string propagates must satisfy an Einstein or an Einstein–like equation. Additionally, there emerge restrictions on the worldsheet curvature, which seems to act as a source for spacetime gravity, even in the absence of other matter...

In this paper we consider the evolution of sets by a fractional mean curvature flow. Our main result states that for any dimension n > 2, there exists an embedded surface in R evolving by fractional mean curvature flow, which developes a singularity before it can shrink to a point. When n > 3 this result generalizes the analogue result of Grayson [18] for the classical mean curvature flow. Inte...

In this paper, by supposing a natural comparison inequality on the positive r-th mean curvatures of the hypersurface, we obtain some new Bernstein-type theorems for complete spacelike hypersurfaces immersed in a semi-Riemannian warped product of constant sectional curvature. Generalizing the above results, under a restriction on the sectional curvature or the Ricci curvature tensor of the fiber...

We investigate the finiteness structure of a complete open Riemannian n-manifold M whose radial curvature at a base point of M is bounded from below by that of a non-compact von Mangoldt surface of revolution with its total curvature greater than π. We show, as our main theorem, that all Busemann functions on M are exhaustions, and that there exists a compact subset of M such that the compact s...

Using Fefferman’s classical result on the boundary singularity of the Bergman kernel, we give an analogous description of the boundary behaviour of various related quantities like the Bergman invariant, the coefficients of the Bergman metric, of the associated Laplace-Beltrami operator, of its curvature tensor, Ricci curvature and scalar curvature. The main point is that even though one would e...

The mean curvature flow arises material science and condensed matter physics and has been recently successfully applied by Huisken and Sinestrari to topological classification of surfaces and submanifolds. It is closely related to the Ricci and inverse mean curvature flow. The most interesting aspect of the mean curvature flow is formation of singularities, which is the main theme of these lect...