Publications associées à Stability Results For The Volume Of Random Simplices

On the boundedness of n-folds with κ(X) = n - 1

In this note, we study certain sufficient conditions for a set of minimal klt pairs ( X, triangle) with kappa ( X, triangle) = dim( X ) - 1 to be bounded. ...

European Mathematical Soc-Ems2024

A lower bound on opaque sets

János Pach

It is proved that the total length of any set of countably many rectifiable curves whose union meets all straight lines that intersect the unit square U is at least 2.00002. This is the first improvement on the lower bound of 2 known since 1964. A similar ...

ELSEVIER SCIENCE BV2019

On the reverse isodiametric problem and Dvoretzky-Rogers-type volume bounds

Matthias Schymura

The isodiametric inequality states that the Euclidean ball maximizes the volume among all convex bodies of a given diameter. We are motivated by a conjecture of Makai Jr. on the reverse question: Every convex body has a linear image whose isodiametric quot ...

2018

New Moduli For Banach Spaces

Grigory Ivanov

Modifying the moduli of supporting convexity and supporting smoothness, we introduce new moduli for Banach spaces which occur, for example, as lengths of catheti of right-angled triangles (defined via so-called quasiorthogonality). These triangles have two ...

Tusi Mathematical Research Group2017

On Simplices in Diameter Graphs in R-4

Andrei Kupavskii

A graph G is a diameter graph in R-d if its vertex set is a finite subset in R-d of diameter 1 and edges join pairs of vertices a unit distance apart. It is shown that if a diameter graph G in R-4 contains the complete subgraph K on five vertices, then any ...

Maik Nauka/Interperiodica/Springer2017

Foldable aircraft with protective cage for transportation and transportability

Dario Floreano, Przemyslaw Mariusz Kornatowski, Stefano Mintchev

An aerial vehicle, configured to transport cargo, and including a propulsion system and a foldable cage is described. The foldable cage is substantially linear while in a folded configuration, and substantially circular while in a deployed configuration. M ...

2017

Comparison-Based Optical Assessment of Hyperboloid and Ellipsoid Reflectors in a Beam-Down Solar Tower System With Linear Fresnel Heliostats

Meng Lin

Beam-down concentrating solar tower (BCST) is known for its merits in easy installation and maintenance as well as lower convection heat loss of the central receiver (CR) when comparing to a traditional concentrated solar tower system. A point-line-couplin ...

ASME2017

Near-field characterization of Bloch surface waves based 2D optical components

Richa Dubey

Bloch surface waves (BSWs) are surface electromagnetic modes that propagate at the interface between a multilayer substrate and a homogeneous external medium. The optical field of the surface mode is confined near the surface of the multilayer. This vertic ...

EPFL2017

Characterization of Surface State of Inert Particles: Case of Si and SiC

Hubert Girault, Fernando Cortes Salazar, Véronique Amstutz, Desire Martial Koutouan Abro

Silicon and Silicon carbide particles have been investigated by the mean of infrared (IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) to establish their surface states. The results of this research are based on the estimation of the area under ...

2016

Upper bounds for the perimeter of plane convex bodies

Filip Moric

We show that the maximum total perimeter of k plane convex bodies with disjoint interiors lying inside a given convex body C is equal to , in the case when C is a square or an arbitrary triangle. A weaker bound is obtained for general plane convex bodies. ...

Springer2014

Exponentiality of the exchange algorithm for finding another room-partitioning

Laura Sanità

Let T be a triangulated surface given by the list of vertex-triples of its triangles, called rooms. A room-partitioning for T is a subset R of the rooms such that each vertex of T is in exactly one room in R. Given a room-partitioning R for T, the exchange ...

Elsevier Science Bv2014

Opaque Sets

János Pach

The problem of finding "small" sets that meet every straight-line which intersects a given convex region was initiated by Mazurkiewicz in 1916. We call such a set an opaque set or a barrier for that region. We consider the problem of computing the shortest ...

Springer2014

Diameter Graphs in R-4

Andrei Kupavskii

A diameter graph in is a graph whose set of vertices is a finite subset of and whose set of edges is formed by pairs of vertices that are at diameter apart. This paper is devoted to the study of different extremal properties of diameter graphs in and on a ...

Springer2014

Two and a half billion years of distance research

János Pach, Filip Moric

In a seminal paper published in 1946, Erd ̋os initiated the investigation of the distribution of distances generated by point sets in metric spaces. In spite of some spectacular par- tial successes and persistent attacks by generations of mathe- maticians, ...

2013

Concrete shells – Towards efficient structures: Construction of an ellipsoidal concrete shell in Switzerland

Aurelio Muttoni, Miguel Fernández Ruiz

Concrete shells have been widely used in the past as economical and suitable solutions for a number of structures such as roofs, silos, cooling towers or offshore platforms. Taking advantage of their single or double curvature, bending moments and shear fo ...

Structural Concrete2013

Erdos-Szekeres-type theorems for monotone paths and convex bodies

János Pach

For any sequence of positive integers j(1)< j(2)= 2 and q >= 2, what is the s ...

London Math Soc2012

Covering Cubes and the Closest Vector Problem

Friedrich Eisenbrand, Nicolai Hähnle, Martin Niemeier

We provide the currently fastest randomized (1+epsilon)-approximation algorithm for the closest vector problem in the infinity-norm. The running time of our method depends on the dimension n and the approximation guarantee epsilon by 2^(O(n))(log(1/epsilon ...

Acm Order Department, P O Box 64145, Baltimore, Md 21264 Usa2011

Etude expérimentale de refuges à poissons aménagés dans les berges de rivières soumises aux éclusées hydroélectriques

Jean-Marc Ribi

Downstream of hydroelectric storage dams, the rivers suffer from rapid, frequent and intense flow variations linked to the power production constraints. Subjected to this hydropeaking phenomenon, the fish population suffers from a known decline. In the res ...

EPFL2011

Percolative properties of hard oblate ellipsoids of revolution with a soft shell

Gianluca Ambrosetti, Peter Ryser, Claudio Grimaldi, Niklaus Johner

We present an in-depth analysis of the geometrical percolation behavior in the continuum of random assemblies of hard oblate ellipsoids of revolution. Simulations were carried out by considering a broad range of aspect-ratios, from spheres up to aspect-rat ...

2008