Concept

Point groups in three dimensions

Patching And Weak Approximation In Isometry Groups

Let R be a semilocal principal ideal domain. Two algebraic objects over R in which scalar extension makes sense (e.g. quadratic spaces) are said to be of the same genus if they become isomorphic after extending scalars to all completions of R and its fract ...

Amer Mathematical Soc2017

Shapes from pixels

Martin Vetterli, Loïc Arnaud Baboulaz, Arash Amini, Mitra Fatemi

Continuous-domain visual signals are usually captured as discrete (digital) images. This operation is not invertible in general, in the sense that the continuous-domain signal cannot be exactly reconstructed based on the discrete image, unless it satisfies ...

Institute of Electrical and Electronics Engineers2016

Unsplittable Coverings in the Plane

János Pach, Doemoetoer Palvoelgyi

A system of sets forms an m-fold covering of a set X if every point of X belongs to at least m of its members. A 1-fold covering is called a covering. The problem of splitting multiple coverings into several coverings was motivated by classical density est ...

Springer-Verlag Berlin2016

Unsplittable coverings in the plane

János Pach, Doemoetoer Palvoelgyi

Academic Press Inc Elsevier Science2016

Spectral signatures of high-symmetry quantum dots and effects of symmetry breaking

Elyahou Kapon, Alok Rudra, Marc-André Dupertuis, Daniel Oberli, Valentina Troncale

High symmetry epitaxial quantum dots (QDs) with three or more symmetry planes provide a very promising route for the generation of entangled photons for quantum information applications. The great challenge to fabricate nanoscopic high symmetry QDs is furt ...

Iop Publishing Ltd2015

High pressure induced spin state crossover in Sr2CaYCo4O10.5

Jonathan White

The layered cobaltite Sr2CaYCo4O10.5 with formal average cobalt oxidation state close to 3+ has been studied as functions of both temperature and pressure up to 4GPa by neutron powder diffraction (NPD). The crystal structure is shown to have tetragonal sym ...

Institute of Physics2015

An indiscrete Bieberbach theorem: from amenable CAT$(0)$ groups to Tits buildings

Nicolas Monod

Non-positively curved spaces admitting a cocompact isometric action of an amenable group are investigated. A classification is established under the assumption that there is no global fixed point at infinity under the full isometry group. The visual bounda ...

2015

Icosahedral quasicrystal-enhanced nucleation of the fcc phase in liquid gold alloys

Michel Rappaz, Güven Kurtuldu, Alberto Sicco

Although the grain refinement of yellow gold alloys with Jr has been used in industry and known for nearly half a century, the basic mechanism is still unknown. The present contribution shows that the mechanism is the same as that evidenced recently in Al- ...

Elsevier2014

Infinite Presentability Of Groups And Condensation

Luc Guyot

We describe various classes of infinitely presented groups that are condensation points in the space of marked groups. A well-known class of such groups consists of finitely generated groups admitting an infinite minimal presentation. We introduce here a l ...

Cambridge University Press2014

L4Fe2As2Te1-xO4-yFy (L = Pr, Sm, Gd): A layered oxypnictide superconductor with T-c up to 45 K

László Forró, Richard Gaal, Janusz Andrzej Karpinski, Andrea Pisoni, Sergiy Katrych

The synthesis and structural and physical properties of iron lanthanide oxypnictide superconductors, L4Fe2As2Te1-xO4 (L = Pr, Sm, Gd), with transition temperature at similar to 25 K are reported. Single crystals have been grown at high pressure using the c ...

Amer Physical Soc2014