Yazar "Perktas, Selcen Yuksel" seçeneğine göre listele

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    Almost bi-slant submanifolds of an almost contact metric manifold
    (Springer Basel Ag, 2021) Perktas, Selcen Yuksel; Blaga, Adara M.; Kilic, Erol
    In this paper we introduce and study the almost bi-slant submanifolds of an almost contact metric manifold. We give some characterization theorems for almost bi-slant submanifolds. Moreover, we obtain integrability conditions of the distributions which are involved in the definition of almost bi-slant submanifolds. We also get some results for totally geodesic and totally umbilical almost bi-slant submanifolds of cosymplectic manifolds and Sasakian manifolds.
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    BIHARMONIC HYPERSURFACES OF LP-SASAKIAN MANIFOLDS
    (Alexandru Ioan Cuza Univ Press, Alexandru Ioan Cuza Univ Iasi, 2011) Perktas, Selcen Yuksel; Kilic, Erol; Keles, Sadik
    In this paper the biharmonic hypersurfaces of Lorentzian para-Sasakian manifolds are studied. We firstly find the biharmonic equation for a hypersurface which admits the characteristic vector field of the Lorentzian para-Sasakian as the normal vector field. We show that a biharmonic spacelike hypersurface of a Lorentzian para-Sasakian manifold with constant mean curvature is minimal. The biharmonicity condition for a hypersurface of a Lorentzian para-Sasakian manifold is investigated when the characteristic vector field belongs to the tangent hyperplane of the hypersurface. We find some necessary and sufficient conditions for a timelike hypersurface of a Lorentzian para-Sasakian manifold to be proper biharmonic. The nonexistence of proper biharmonic timelike hypersurfaces with constant mean curvature in a Ricci flat Lorentzian para-Sasakian manifold is proved.
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    Einstein like (?)-para Sasakian manifolds
    (Academic Publication Council, 2013) Keles, Sadik; Kilic, Erol; Tripathi, Mukut Mani; Perktas, Selcen Yuksel
    Einstein like (epsilon)-para Sasakian manifolds are introduced. For an (epsilon)-para Sasakian manifold to be Einstein like, a necessary and sufficient condition in terms of its curvature tensor is obtained. The scalar curvature of an Einstein like (epsilon)-para Sasakian manifold is obtained and it is shown that the scalar curvature in this case must satisfy certain differential equation. A necessary and sufficient condition for an (epsilon)-almost paracontact metric hypersurface of an indefinite locally Riemannian product manifold to be (epsilon)-para Sasakian is obtained and it is proved that the (epsilon)-para Sasakian hypersurface of an indefinite locally Riemannian product manifold of almost constant curvature is always Einstein like.
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    HYPERSURFACES OF LORENTZIAN PARA-SASAKIAN MANIFOLDS
    (Matematisk Inst, 2011) Perktas, Selcen Yuksel; Kilic, Erol; Keles, Sadik
    In this paper we study the invariant and noninvariant hypersurfaces of (1, 1, 1) almost contact manifolds, Lorentzian almost paracontact manifolds and Lorentzian para-Sasakian manifolds, respectively. We show that a noninvariant hypersurface of an ( I, 1, 1) almost contact manifold admits an almost product structure. We investigate hypersurfaces of affinely cosymplectic and normal (1, 1, 1) almost contact manifolds. It is proved that a noninvariant hypersurface of a Lorentzian almost paracontact manifold is an almost product metric manifold. Some necessary and sufficient conditions have been given for a non invariant hypersurface of a Lorentzian para-Sasakian manifold to be locally product manifold. We establish a Lorentzian para-Sasakian structure for an invariant hypersurface of a Lorentzian para-Sasakian manifold. Finally we give some examples for invariant and noninvariant hypersurfaces of a Lorentzian para-Sasakian manifold.
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    ON A SEMI-SYMMETRIC NON-METRIC CONNECTION IN AN LP-SASAKIAN MANIFOLD
    (Int Electronic Journal Geometry, 2010) Perktas, Selcen Yuksel; Kilic, Erol; Keles, Sadik
    In this paper we study some properties of curvature tensor, projective curvature tensor, nu-Weyl projective tensor, concircular curvature tensor, conformal curvature tensor, quasi-conformal curvature tensor with respect to semi-symmetric non-metric connection in a Lorentzian para-Sasakian (briefly LP-Sasakian) manifold. It is shown that an LP-Sasakian manifold (M-n, g)(n > 3) with the semi-symmetric non-metric connection is an eta-Einstein manifold.
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    On f-Kenmotsu 3-manifolds with respect to the Schouten-van Kampen connection
    (Tubitak Scientific & Technological Research Council Turkey, 2021) Perktas, Selcen Yuksel; YILDIZ, Ahmet
    In this paper we study some semisymmetry conditions and some soliton types on f-Kenmotsu 3-manifolds with respect to the Schouten-van Kampen connection.
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    On Lightlike Geometry of Para-Sasakian Manifolds
    (Hindawi Publishing Corporation, 2014) Acet, Bilal Eftal; Perktas, Selcen Yuksel; Kilic, Erol
    We study lightlike hypersurfaces of para-Sasakian manifolds tangent to the characteristic vector field. In particular, we define invariant lightlike hypersurfaces and screen semi-invariant lightlike hypersurfaces, respectively, and give examples. Integrability conditions for the distributions on a screen semi-invariant lightlike hypersurface of para-Sasakian manifolds are investigated. We obtain a para-Sasakian structure on the leaves of an integrable distribution of a screen semi-invariant lightlike hypersurface.
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    On Quasi-Sasakian 3-Manifolds with Respect to the Schouten-van Kampen Connection
    (Int Electronic Journal Geometry, 2020) Perktas, Selcen Yuksel; Yildiz, Ahmet
    In this paper we study some soliton types on a quasi-Sasakian 3-manifold with respect to the Schouten-van Kampen connection.
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    On some types of light-like submanifolds of poly-Norden semi-Riemannian manifolds
    (Univ Nis, Fac Sci Math, 2023) Acet, Tuba; Perktas, Selcen Yuksel; Kilic, Erol
    In this paper, we initiate the study of poly-Norden generalized CR-light-like submanifolds and poly-Norden screen transversal CR-light-like submanifolds of poly-Norden semi-Riemannian manifolds. We give examples for such types light-like submanifolds and investigate the conditions for both integrability and totally geodesic foliation descriptions of distributions.
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    ON TRANS-SASAKIAN 3-MANIFOLDS WITH symbolscript DEFORMATION WITH REGARD TO THE SCHOUTEN-VAN KAMPEN CONNECTION
    (Publications L Institut Mathematique Matematicki, 2022) Zeren, Semra; Yildiz, Ahmet; Perktas, Selcen Yuksel
    We study some soliton types on trans-Sasakian 3-manifolds with Da-homotetic deformation with regard to the Schouten-van Kampen connec-tion.
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    RICCI SOLITONS IN 3-DIMENSIONAL NORMAL ALMOST PARACONTACT METRIC MANIFOLDS
    (Int Electronic Journal Geometry, 2015) Perktas, Selcen Yuksel; Keles, Sadik
    In the present paper we study 3-dimensional normal almost paracontact metric manifolds admitting Ricci solitons and gradient Ricci solitons. We give an example of 3-dimensional normal almost paracontact metric manifold. It is shown that if in a 3-dimensional normal almost paracontact metric manifold with alpha, beta = constant the metric is Ricci soliton, where potential vector field V is collinear with the characteristic vector field xi, then the manifold is eta-Einstein. We also prove that an eta-Einstein 3-dimensional normal almost paracontact metric manifold with alpha, beta = constant and V = xi admits a Ricci soliton. Furthermore, we show that if a 3-dimensional normal almost paracontact metric manifold admits a Ricci soliton (g, xi, lambda) then the Ricci soliton is shrinking.
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    Ricci Solitons in 3-Dimensional Normal Almost Paracontact Metric Manifolds (vol 8, pg 34, 2015)
    (Int Electronic Journal Geometry, 2017) Perktas, Selcen Yuksel; Keles, Sadik
    The authors would like to correct some errors which appear in the orginal publication of the article Ricci Solitons in 3-Dimensional Normal Almost Paracontact Metric Manifolds [Int. Electron. J. Geom., Vol. 8, No: 2, 2015, 34-45.].
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    SOME CURVATURE PROPERTIES ON PARACONTACT METRIC (k, ?)-MANIFOLDS WITH RESPECT TO THE SCHOUTEN-VAN KAMPEN CONNECTION
    (Univ Nis, 2021) Yildiz, Ahmet; Perktas, Selcen Yuksel
    The object of the present paper is to characterize paracontact metric (k, mu)-manifolds satisfying certain semisymmetry curvature conditions with respect to the Schouten-van Kampen connection.
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    Some results on paracontact metric (k, ?)-manifolds with respect to the Schouten-van Kampen connection
    (Hacettepe Univ, Fac Sci, 2022) Perktas, Selcen Yuksel; De, Uday Chand; Yildiz, Ahmet
    In the present paper we study certain symmetry conditions and some types of solitons on paracontact metric (k, mu)-manifolds with respect to the Schouten-van Kampen connection. We prove that a Ricci semisymmetric paracontact metric (k, mu)-manifold with respect to the Schouten-van Kampen connection is an g-Einstein manifold. We investigate paracontact metric (k, mu)-manifolds satisfying (sic) . (sic)(cur) = 0 with respect to the Schouten-van Kampen connection. Also, we show that there does not exist an almost Ricci soliton in a (2n + 1)-dimensional paracontact metric (k, mu)-manifold with respect to the Schouten-van Kampen connection such that k > -1 or k < -1. In case of the metric is being an almost gradient Ricci soliton with respect to the Schouten-van Kampen connection, then we state that the manifold is either N(k)-paracontact metric manifold or an Einstein manifold. Finally, we present some results related to almost Yamabe solitons in a paracontact metric (k, mu)-manifold equipped with the Schouten-van Kampen connection and construct an example which verifies some of our results.
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    Warped product submanifolds of Lorentzian paracosymplectic manifolds
    (Springer Heidelberg, 2012) Perktas, Selcen Yuksel; Kilic, Erol; Keles, Sadik
    In this paper we study the warped product submanifolds of a Lorentzian paracosymplectic manifold and obtain some nonexistence results. We show that a warped product semi-invariant submanifold in the form M = M-inverted perpendicular x (f) M-perpendicular to of a Lorentzian paracosymplectic manifold such that the characteristic vector field is normal to M is a usual Riemannian product manifold where totally geodesic and totally umbilical submanifolds of warped product are invariant and anti-invariant, respectively. We prove that the distributions involved in the definition of a warped product semi-invariant submanifold are always integrable. A necessary and sufficient condition for a semi-invariant submanifold of a Lorentzian paracosymplectic manifold to be warped product semi-invariant submanifold is obtained. We also investigate the existence and nonexistence of warped product semi-slant and warped product anti-slant submanifolds in a Lorentzian paracosymplectic manifold.