Results 11 to 20 of about 104 (91)
Homothety curvature homogeneity and homothety homogeneity [PDF]
Annals of Global Analysis and Geometry, 2015 This article supersedes arXiv:1309 ...
García-Río, E. +2 more
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On the homothety conjecture [PDF]
Indiana University Mathematics Journal, 2011 Let $K$ be a convex body in $\bbR^n$ and $\d>0$. The homothety conjecture asks: Does $K_{\d}=c K$ imply that $K$ is an ellipsoid? Here $K_{\d}$ is the (convex) floating body and $c$ is a constant depending on $\d$ only. In this paper we prove that the homothety conjecture holds true in the class of the convex bodies $B^n_p$, $1\leq p\leq \infty ...
Werner, Elisabeth M., Ye, Deping
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Interferometric apodization by homothety – II. Experimental validation
Monthly Notices of the Royal Astronomical Society, 2023 ABSTRACT This work presents the results of experimental laboratory tests on the apodization of circular and rectangular apertures using the Interferometric Apodization by Homothety (IAH) technique. The IAH approach involves splitting the amplitude of the instrumental PSF into two equal parts.
J Chafi +6 more
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Interferometric apodization by homothety – I. Optimization of the device parameters
Monthly Notices of the Royal Astronomical Society, 2023 ABSTRACT This study is focused on the very high dynamic imaging field, specifically the direct observation of exoplanetary systems. The coronagraph is an essential technique for suppressing the star’s light, making it possible to detect an exoplanet with a very weak luminosity compared to its host star. Apodization improves the rejection
J Chafi +6 more
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Topological homotheties on compact Hausdorff spaces [PDF]
Proceedings of the American Mathematical Society, 1969 It is the purpose of this note to extend this result to nonmetrizable compact Hausdorff spaces, replacing the role of metrics by generating families of pseudometrics. Let X be a completely regular space. A family aDE= {Pa f } of pseudometrics pa(x, y) on X will be called a generating family on X iff it generates the topology of X. (The system of sets B
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On a class of topological conjugacy with a homothety
Zhurnal Srednevolzhskogo Matematicheskogo Obshchestva, 2020 We consider a class H(Rn) of orientation-preserving homeomorphisms of Euclidean space Rn such that for any homeomorphism h∈H(Rn) and for any point x∈Rn a condition limn→+∞hn(x)→O holds, were O is the origin. It is proved that for any n≥1 an arbitrary homeomorphism h∈H(Rn) is topologically conjugated with the homothety an:Rn→Rn, given by an(x1,…,an ...
Elena Ya. Gurevich, Aleksey A. Makarov
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Homothety Curvature Homogeneity
, 2013 We examine the difference between several notions of curvature homogeneity and show that the notions introduced by Kowalski and Vanžurová are genuine generalizations of the ordinary notion of $k$-curvature homogeneity. The homothety group plays an essential role in the analysis.
García-Río, E. +2 more
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Some Properties of Ruled Surfaces under Homothety in E3 [PDF]
Mathematical and Computational Applications, 2002 It is clearly that, If f : E3→E3 is a homothety and \(\varphi\) is a surface in three dimensional Euclidean space E3, \(f(\varphi) = \overline{\varphi}\) is also a surface in E3. In this paper, the surface \(\varphi\) has been taken a ruled surface, specially. It was shown that image surface \(f(\varphi) = \overline{\varphi}\) has been a ruled surface,
Kasap E., Yüce S., Kuruoğlu N.
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Four‐Dimensional pp‐Wave Lie Groups and Harmonic Curvature
Mathematische Nachrichten, Volume 299, Issue 7, Page 1751-1780, July 2026.ABSTRACT We determine all four‐dimensional Lie groups which have harmonic curvature. In parallel, a description of four‐dimensional pp‐wave Lie groups is obtained.
E. García‐Río +2 more
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Proper 3‐realizability and second cohomology of groups on two generators of finite order
Bulletin of the London Mathematical Society, Volume 58, Issue 7, July 2026.Abstract Given an (infinite) finitely generated group G$G$, its first cohomology group H1(G;ZG)$H^1(G;{\mathbb {Z}}G)$ is free abelian and “counts” the number of ends of G$G$ which equals 1+rank(H1(G;ZG))$1 + rank (H^1(G;{\mathbb {Z}}G))$. The question whether or not for every finitely presented group G$G$ its second cohomology group H2(G;ZG)$H^2(G ...
Francisco F. Lasheras, R. Roy
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