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In recent years, three-dimensional point clouds are used increasingly to document natural environments. Each dataset contains a diverse set of objects, at varying shapes and sizes, distributed throughout the data and intricately intertwined…

Computer Vision and Pattern Recognition · Computer Science 2024-08-27 Reuma Arav , Dennis Wittich , Franz Rottensteiner

Aerosols are ubiquitous, and particle capture from particle-laden air as it flows past an obstacle is of widespread practical importance. Neglecting diffusion, previous work has shown that for a smooth curved surface in both Stokes flow and…

Fluid Dynamics · Physics 2025-02-26 Joshua F. Robinson , Patrick B. Warren , Matthew R. Turner , and Richard P. Sear

Porous media are often modelled as systems of overlapping obstacles, which leads to the problem of two percolation thresholds in such systems, one for the porous matrix and the other one for the void space. Here we investigate these…

Statistical Mechanics · Physics 2016-06-28 Zbigniew Koza , Grzegorz Kondrat , Karol Suszczyński

Calculating by analytical theory the deformation of finite-sized elastic bodies in response to internally applied forces is a challenge. Here, we derive explicit analytical expressions for the amplitudes of modes of surface deformation of a…

Soft Condensed Matter · Physics 2024-07-15 Lukas Fischer , Andreas M. Menzel

The disagreement between low- and high-redshift measurements of the Hubble parameter is emerging as a serious challenge to the standard model of cosmology. We develop a covariant cosmographic analysis of the Hubble parameter in a general…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-13 Roy Maartens , Jessica Santiago , Chris Clarkson , Basheer Kalbouneh , Christian Marinoni

Surface area and mean width of a cylinder (the convex hull of two parallel disks) in R^3 are computed. It is more difficult to obtain analogous results for a cone (the convex hull of a disk D and a point p). Oblique formulas for mean width,…

Metric Geometry · Mathematics 2013-01-01 Steven R. Finch

We derive a covariance formula for the number of excursion or level set components of a smooth stationary Gaussian field on $\mathbb{R}^d$ contained in compact domains. We also present two applications of this formula: (1) for fields whose…

Probability · Mathematics 2025-10-10 Dmitry Beliaev , Michael McAuley , Stephen Muirhead

The aim of this paper is to study dynamical and topological properties of a flow in the region of influence of an isolated non-saddle set. We see, in particular, that some topological conditions are sufficient to guarantee that these sets…

Dynamical Systems · Mathematics 2020-03-18 Héctor Barge , José M. R. Sanjurjo

The Universe is a physical object. Physical objects have shapes and sizes. General relativity is insufficient to describe the global shape and size of the Universe: the Hilbert-Einstein equations only treat limiting quantities towards an…

Astrophysics · Physics 2007-05-23 B. F. Roukema

We study the structure of a uniformly randomly chosen partial order of width 2 on n elements. We show that under the appropriate scaling, the number of incomparable elements converges to the height of a one dimensional Brownian excursion at…

Probability · Mathematics 2013-06-24 Nayantara Bhatnagar , Nick Crawford , Elchanan Mossel , Arnab Sen

We bridge the properties of the regular square and honeycomb Voronoi tessellations of the plane to those of the Poisson-Voronoi case, thus analyzing in a common framework symmetry-break processes and the approach to uniformly random…

Statistical Mechanics · Physics 2011-10-11 Valerio Lucarini

We study nonlinear surface modes in two-dimensional {\em anisotropic} periodic photonic lattices and demonstrate that, in a sharp contrast to one-dimensional discrete surface solitons, the mode threshold power is lower at the surface, and…

Pattern Formation and Solitons · Physics 2015-06-26 Rodrigo A. Vicencio , Sergej Flach , Mario I. Molina , Yuri S. Kivshar

We calculate the asymptotic average rate at which a generic geodesic on a finite area hyperbolic 2-orbifold returns to a subsurface with geodesic boundary. As a consequence we get the average time a generic geodesic spends in such a…

Dynamical Systems · Mathematics 2011-02-24 Andrew Haas

We study the spatial isosceles three body problem, which is a system with two degrees of freedom after modulo the rotation symmetry. For certain choices of energy and angular momentum, we find some disk-like global surfaces of section with…

Dynamical Systems · Mathematics 2023-08-08 Xijun Hu , Lei Liu , Yuwei Ou , Guowei Yu

Recently, a tree bijection has been found for planar hyperbolic surfaces, which allows for an easy computation of the Weil--Petersson volumes, and opens the path to get distance statistic on random hyperbolic surfaces and to find scaling…

Geometric Topology · Mathematics 2025-12-12 Bart Zonneveld

We consider microlensing of an elliptical source crossing a fold caustic. We derive a simple expression for the light curve of a source with uniform surface brightness that is accurate to third order in the ellipticity e (yielding errors of…

Astrophysics · Physics 2007-05-23 B. Scott Gaudi , Zoltan Haiman

The convex hull of N independent random points chosen on the boundary of a simple polytope in R^n is investigated. Asymptotic formulas for the expected number of vertices and facets, and for the expectation of the volume difference are…

Probability · Mathematics 2022-01-11 M. Reitzner , C. Schuett , E. M. Werner

We investigate the motion of a suspended non-Brownian sphere past a fixed cylindrical or spherical obstacle in the limit of zero Reynolds number for arbitrary particle-obstacle aspect ratios. We consider both a suspended sphere moving in a…

Fluid Dynamics · Physics 2016-05-04 Sumedh R. Risbud , German Drazer

The simplest stochastic halo formation models assume that the traceless part of the shear field acts to increase the initial overdensity (or decrease the underdensity) that a protohalo (or protovoid) must have if it is to form by the…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-09 Marcello Musso , Ravi K. Sheth

A stationary rotating surface is a compact surface in Euclidean space whose mean curvature $H$ at each point $x$ satisfies $2H(x)=a r^2+b$, where $r$ is the distance from $x$ to a fixed straight-line $L$, and $a$ and $b$ are constants.…

Differential Geometry · Mathematics 2008-09-24 Rafael López