• Title/Summary/Keyword: Gaussian and Mean Curvatures

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LORENTZIAN SURFACES WITH CONSTANT CURVATURES AND TRANSFORMATIONS IN THE 3-DIMENSIONAL LORENTZIAN SPACE

  • Park, Joon-Sang
    • Journal of the Korean Mathematical Society
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    • v.45 no.1
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    • pp.41-61
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    • 2008
  • We study Lorentzian surfaces with the constant Gaussian curvatures or the constant mean curvatures in the 3-dimensional Lorentzian space and their transformations. Such surfaces are associated to the Lorentzian Grassmannian systems and some transformations on such surfaces are given by dressing actions on those systems.

ON SOME GEOMETRIC PROPERTIES OF QUADRIC SURFACES IN EUCLIDEAN SPACE

  • Ali, Ahmad T.;Aziz, H.S. Abdel;Sorour, Adel H.
    • Honam Mathematical Journal
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    • v.38 no.3
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    • pp.593-611
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    • 2016
  • This paper is concerned with the classifications of quadric surfaces of first and second kinds in Euclidean 3-space satisfying the Jacobi condition with respect to their curvatures, the Gaussian curvature K, the mean curvature H, second mean curvature $H_{II}$ and second Gaussian curvature $K_{II}$. Also, we study the zero and non-zero constant curvatures of these surfaces. Furthermore, we investigated the (A, B)-Weingarten, (A, B)-linear Weingarten as well as some special ($C^2$, K) and $(C^2,\;K{\sqrt{K}})$-nonlinear Weingarten quadric surfaces in $E^3$, where $A{\neq}B$, A, $B{\in}{K,H,H_{II},K_{II}}$ and $C{\in}{H,H_{II},K_{II}}$. Finally, some important new lemmas are presented.

SURFACES WITH CONSTANT GAUSSIAN AND MEAN CURVATURES N THE ANTI-DE SITTER SPACE ℍ31

  • Ugur Dursun
    • Honam Mathematical Journal
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    • v.46 no.2
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    • pp.249-266
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    • 2024
  • In this work, we study time-like and space-like surfaces invariant by a group of translation isometries of the half-space model ℋ31 of the anti-de Sitter space ℍ31 . We determine all such surfaces with constant mean curvature and constant Gaussian curvature. We also obtain umbilical surfaces of ℋ31.

On Ruled Surfaces with a Sannia Frame in Euclidean 3-space

  • Senyurt, Suleyman;Eren, Kemal
    • Kyungpook Mathematical Journal
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    • v.62 no.3
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    • pp.509-531
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    • 2022
  • In this paper we define a new family of ruled surfaces using an othonormal Sannia frame defined on a base consisting of the striction curve of the tangent, the principal normal, the binormal and the Darboux ruled surface. We examine characterizations of these surfaces by first and second fundamental forms, and mean and Gaussian curvatures. Based on these characterizations, we provide conditions under which these ruled surfaces are developable and minimal. Finally, we present some examples and pictures of each of the corresponding ruled surfaces.

SOME SPECIAL SMARANDACHE RULED SURFACES BY FRENET FRAME IN E3-II

  • Suleyman, Senyurt;Davut, Canli;Elif, Can;Sumeyye Gur, Mazlum
    • Honam Mathematical Journal
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    • v.44 no.4
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    • pp.594-617
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    • 2022
  • In this study, firstly Smarandache ruled surfaces whose base curves are Smarandache curves derived from Frenet vectors of the curve, and whose direction vectors are unit vectors plotting Smarandache curves, are created. Then, the Gaussian and mean curvatures of the obtained ruled surfaces are calculated separately, and the conditions to be developable or minimal for the surfaces are given. Finally, the examples are given for each surface and the graphs of these surfaces are drawn.

ON THE CURVATURE FUNCTIONS OF TUBE-LIKE SURFACES IN THE GALILEAN SPACE

  • Abdel-Aziz, Hossam Eldeen S.;Sorour, Adel H.
    • Communications of the Korean Mathematical Society
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    • v.36 no.3
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    • pp.609-622
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    • 2021
  • In the Galilean space G3, we study a special kind of tube surfaces, called tube-like surfaces. They are defined by sweeping a space curve along another central space curve. In this setting, we investigate some equations in terms of Gaussian and mean curvatures, showing some relevant theorems. Our theoretical results are illustrated with some plotted examples.

Classification of Ruled Surfaces with Non-degenerate Second Fundamental Forms in Lorentz-Minkowski 3-Spaces

  • Jung, Sunmi;Kim, Young Ho;Yoon, Dae Won
    • Kyungpook Mathematical Journal
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    • v.47 no.4
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    • pp.579-593
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    • 2007
  • In this paper, we study some properties of ruled surfaces in a three-dimensional Lorentz-Minkowski space related to their Gaussian curvature, the second Gaussian curvature and the mean curvature. Furthermore, we examine the ruled surfaces in a three-dimensional Lorentz-Minkowski space satisfying the Jacobi condition formed with those curvatures, which are called the II-W and the II-G ruled surfaces and give a classification of such ruled surfaces in a three-dimensional Lorentz-Minkowski space.

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CANAL HYPERSURFACES GENERATED BY NON-NULL CURVES IN LORENTZ-MINKOWSKI 4-SPACE

  • Mustafa Altin;Ahmet Kazan;Dae Won Yoon
    • Bulletin of the Korean Mathematical Society
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    • v.60 no.5
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    • pp.1299-1320
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    • 2023
  • In the present paper, firstly we obtain the general expression of the canal hypersurfaces that are formed as the envelope of a family of pseudo hyperspheres, pseudo hyperbolic hyperspheres and null hyper-cones whose centers lie on a non-null curve with non-null Frenet vector fields in E41 and give their some geometric invariants such as unit normal vector fields, Gaussian curvatures, mean curvatures and principal curvatures. Also, we give some results about their flatness and minimality conditions and Weingarten canal hypersurfaces. Also, we obtain these characterizations for tubular hypersurfaces in E41 by taking constant radius function and finally, we construct some examples and visualize them with the aid of Mathematica.

CMC SURFACES FOLIATED BY ELLIPSES IN EUCLIDEAN SPACE E3

  • Ali, Ahmad Tawfik
    • Honam Mathematical Journal
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    • v.40 no.4
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    • pp.701-718
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    • 2018
  • In this paper, we will study the constant mean curvature (CMC) surfaces foliated by ellipses in three dimensional Euclidean space $E^3$. We prove that: (1): Surfaces foliated by ellipses are CMC surfaces if and only if it is a part of generalized cylinder. (2): All surfaces foliated by ellipses are not minimal surfaces. (3): CMC surfaces foliated by ellipses are developable surfaces. (4): CMC surfaces foliated by ellipses are translation surfaces generated by a straight line and plane curve.