Results 1 to 10 of about 391 (45)
Examples of noncompact nonpositively curved manifolds
Bulletin of the London Mathematical Society, Volume 53, Issue 4, Page 1061-1071, August 2021., 2021 Abstract We give a simple construction of new, complete, finite volume manifolds M of bounded, nonpositive curvature. These manifolds have ends that look like a mixture of locally symmetric ends of different ranks and their fundamental groups are not duality groups.
Grigori Avramidi +1 more
wiley +1 more source
Mannheim curves and their partner curves in Minkowski 3-space E13
Demonstratio Mathematica, 2022 The modified orthogonal frame is an important tool to study analytic space curves whose curvatures have discrete zero points. In this article, by using the modified orthogonal frame, Mannheim curves and their partner curves are investigated in Minkowski ...
Elsharkawy Ayman, Elshenhab Ahmed M.
doaj +1 more source
On Menelaus’ and Ceva’s theorems in Nil geometry
Acta Universitatis Sapientiae: Mathematica, 2023 In this paper we deal with Nil geometry, which is one of the homogeneous Thurston 3-geometries. We define the “surface of a geodesic triangle” using generalized Apollonius surfaces. Moreover, we show that the “lines” on the surface of a geodesic triangle
Szirmai Jenő
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Curves in the Lorentz-Minkowski plane with curvature depending on their position
Open Mathematics, 2020 Motivated by the classical Euler elastic curves, David A. Singer posed in 1999 the problem of determining a plane curve whose curvature is given in terms of its position. We propound the same question in the Lorentz-Minkowski plane, focusing on spacelike
Castro Ildefonso +2 more
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On the dual quaternion geometry of screw motions
Analele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica, 2023 In this study, the screw motions are studied using dual quaternions with the help of di erent perspectives. Firstly, orthogonality definition of dual quaternions is given and geometric interpretation of orthogonality condition is made.
Erişir Tülay +3 more
doaj +1 more source
Elastic Sturmian spirals in the Lorentz-Minkowski plane
Open Mathematics, 2016 In this paper we consider some elastic spacelike and timelike curves in the Lorentz-Minkowski plane and obtain the respective vectorial equations of their position vectors in explicit analytical form.
Uçum Ali +2 more
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Helicoidal Surfaces in Galilean Space With Density
Frontiers in Physics, 2020 In this paper, we construct helicoidal surfaces in the three dimensional Galilean space G3. The First and the Second Fundamental Forms for such surfaces will be obtained. Also, mean and Gaussian curvature given by smooth functions will be derived.
Safaa Mosa +3 more
doaj +1 more source
On the type of triangle groups [PDF]
Geometriae Dedicata (2007) 130 (1): 137-148, 2007 We prove a conjecture of R. Schwartz about the type of some complex hyperbolic triangle groups.
arxiv +1 more source
On the curvature of nonregular saddle surfaces in the hyperbolic and spherical three‐space
Abstract and Applied Analysis, Volume 7, Issue 3, Page 113-123, 2002., 2002 This paper proves that any nonregular nonparametric saddle surface in a three‐dimensional space of nonzero constant curvature k, which is bounded by a rectifiable curve, is a space of curvature not greater than k in the sense of Aleksandrov. This generalizes a classical theorem by Shefel′ on saddle surfaces in 𝔼3.
Dimitrios E. Kalikakis
wiley +1 more source
A characterization of regular saddle surfaces in the hyperbolic and spherical three‐space
Abstract and Applied Analysis, Volume 7, Issue 7, Page 349-355, 2002., 2002 We prove that the class of regular saddle surfaces in the hyperbolic or spherical three‐space coincides with the class of regular surfaces with curvature not greater than the curvature of the surrounding space. We also show that a similar result for nonregular surfaces is incorrect.
Dimitrios E. Kalikakis
wiley +1 more source