We consider a nearly hyperbolic Kenmotsu manifold admitting a semi-symmetric metric connection and study semi-invariant submanifolds of a nearly hyperbolic Kenmotsu manifold with semi-symmetric metric connection. We also find the integrability conditions of some distributions on nearly hyperbolic Kenmotsu manifold andstudy parallel distributions on nearly hyperbolic Kenmotsu manifold.
9953056974 Call Girls In South Ex, Escorts (Delhi) NCR.pdf
On Semi-Invariant Submanifolds of a Nearly Hyperbolic Kenmotsu Manifold with Semi-symmetric Metric Connection
1. TOUKEER KHANet al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 4, Issue 9( Version 3), September 2014, pp.61-69
www.ijera.com 61|P a g e
On Semi-Invariant Submanifolds of a Nearly Hyperbolic Kenmotsu Manifold with Semi-symmetric Metric Connection TOUKEER KHAN1, SHADAB AHMAD KHAN2 AND MOBIN AHMAD3 1,2 Department of Mathematics,Integral University, Kursi Road, Lucknow-226026, India. 3Department of Mathematics,Faculty of Science, Jazan University, Jazan-2069, Saudi Arabia. Abstract We consider a nearly hyperbolic Kenmotsu manifold admitting a semi-symmetric metric connection and study semi-invariant submanifolds of a nearly hyperbolic Kenmotsu manifold with semi-symmetric metric connection. We also find the integrability conditions of some distributions on nearly hyperbolic Kenmotsu manifold andstudy parallel distributions on nearly hyperbolic Kenmotsu manifold. Key Words and Phrases: Semi-invariant submanifolds, Nearly hyperbolic Kenmotsu manifold, Semi-symmetric metric connection, Parallel distribution, Integrability condition. 2000 AMS Mathematics Subject Classification: 53D05, 53D25, 53D12.
I. Introduction
Let ∇ be a linear connection in an n-dimensional differentiable manifoldM . The torsion tensor T and curvature tensor R of ∇ given respectively by 푇 푋,푌 =훻푋푌−훻푌푋− 푋,푌 , 푅 푋,푌 푍=∇푋∇푌푍−∇푌∇푋푍−∇[푋,푌]푍. The connection ∇ is symmetric if its torsion tensor T vanishes, otherwise it is non-symmetric. The connection ∇ is metric connection if there is a Riemannian metric g in 푀 such that 훻푔=0, otherwise it is non-metric. It is well known that a linear connection is symmetric and metric if and only if it is the Levi-Civita connection. A. Friedmann and J. A. Schouten introduced the idea of a semi- symmetric connection. A linear connection is said to be a semi-symmetric connection if its torsion tensor T is of the form: 푇 푋,푌 =휂 푋 푌−휂 푌 푋. Many geometers (see,[20], [21]) have studied some properties of semi-symmetric metric connection.
The study of CR-submanifolds of Kaehler manifold as generalization of invariant and anti- invariant submanifolds was initiated by A. Bejancu in [8]. A semi-invariant submanifold is the extension of a CR-submanifold of a Kaehler manifold to submanifolds of almost contact manifolds. The study of semi-invariant submanifolds of Sasakian manifolds was initiated by Bejancu-Papaghuic in [10]. The same concept was studied under the name contact CR-submanifold by Yano-Kon in [19] and K. Matsumoto in [16].The study of semi-invariant submanifolds in almost contact manifold was enriched by several geometers (see, [2], [4], [5], [6], [7], [8], [12], [13], [17]). On the otherhand, almost hyperbolic 푓,휉,휂,푔 -structure was defined and studied by Upadhyay and Dube in [18].Joshi and Dube studied semi-invariant submanifolds of an almost r-contact hyperbolic metric manifold in [15]. Ahmad M., K. Ali, studied semi-invariant submanifolds of a nearly hyperbolic Kenmotsu manifold with a semi-symmetric non-metric connection in [2]. In this paper, we study semi- invariant submanifolds of a nearly hyperbolic Kenmotsu manifold admitting a semi-symmetric metric connection.
RESEARCH ARTICLE OPEN ACCESS
2. TOUKEER KHANet al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 4, Issue 9( Version 3), September 2014, pp.61-69
www.ijera.com 62|P a g e
This paper is organized as follows. In section 2, we give a brief description of nearly hyperbolic Kenmotsu manifold admitting a semi- symmetric metric connection. In section 3, we study some properties of semi-invariant submanifolds of a nearly hyperbolic Kenmotsu manifold with a semi- symmetric metric connection. In section 4,we discuss the integrability conditions of some distributions on nearly hyperbolic Kenmotsu manifold with a semi- symmetric metric connection. In section 5, we study parallel horizontal distribution on nearly hyperbolic Kenmotsu manifold with a semi-symmetric metric connection.
II. Preliminaries
Let 푀 be an 푛-dimensional almost hyperbolic contact metric manifold with the almost hyperbolic contact metric structure ∅,휉,휂,푔 , where a tensor ∅ of type 1,1 , a vector field 휉, called structure vector field and 휂, the dual 1-form of 휉and the associated Riemannian metric 푔satisfying the following ∅2푋=푋+휂 푋 휉, 푔 푋,휉 =휂 푋 (2.1) 휂 휉 =−1, ∅ 휉 =0, 휂표∅=0, (2.2) 푔 ∅푋,∅푌 =−푔 푋,푌 −휂 푋 휂 푌 (2.3) for any 푋,푌 tangent to 푀 [19]. In this case 푔 ∅푋,푌 =−푔 ∅푌,푋 . (2.4) An almost hyperbolic contact metric structure ∅,휉,휂,푔 on 푀 is called hyperbolic Kenmotsu manifold [7] if and only if ∇푋∅ 푌=푔 ∅푋,푌 − 휂(푌)∅푋 (2.5) for all 푋,푌 tangent to 푀 . On a hyperbolic Kenmotsu manifold푀 , we have ∇푋휉=푋+ 휂(푋)휉 (2.6) for a Riemannian metric g and Riemannian connection∇. Further, an almost hyperbolic contact metric manifold 푀 on ∅,휉,휂,푔 is called a nearly hyperbolic Kenmotsu manifold [7], if ∇푋∅ 푌+ ∇푌∅ 푋=−휂 푋 ∅푌− 휂 푌 ∅푋, (2.7) where∇ is Riemannian connection 푀 . Now, we define a semi-symmetric metric connection ∇ 푋푌=∇푋푌+휂 푌 푋−푔(푋,푌)휉 (2.8) Such that(∇ 푋푔) 푌,푍 =0.From(2.7) and(2.8), replacing 푌by ∅푌, we have ∇ 푋∅ 푌+ ∇ 푌∅ 푋=−2휂 푋 ∅푌−2휂 푌 ∅푋 (2.9) ∇ 푋휉=0. (2.10) An almost hyperbolic contact metric manifold with almost hyperbolic contact structure ∅,휉,휂,푔 is called nearly hyperbolic Kenmotsu manifold with semi-symmetric metric connection if it is satisfied (2.9) and (2.10). Let Riemannian metric symbol 푔 and ∇ be induced Levi-Civita connection on 푀 then the Guass formula and Weingarten formula is given by ∇ 푋푌=∇푋푌+푕 푋,푌 , (2.11) ∇ 푋푁=−퐴푁푋+∇푋 ⊥푁 (2.12)
3. TOUKEER KHANet al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 4, Issue 9( Version 3), September 2014, pp.61-69
www.ijera.com 63|P a g e
for any 푋,푌 ∈푇푀 and 푁∈푇푀, where ∇ is a connection on the normal bundle 푇푀, 푕is the second fundamental form and 퐴푁 is the Weingarten map associated with 푁 as 푔 푕 푋,푌 ,푁 =푔 퐴푁푋,푌 . (2.13) Any vector 푋 tangent to 푀 is given as 푋=푃푋+푄푋+휂 푋 휉, (2.14) where푃푋∈퐷 푎푛푑 푄푋∈퐷⊥. For any 푁 normal to 푀, we have ∅푁=퐵푁+퐶푁, (2.15) where퐵푁 푟푒푠푝.퐶푁 is the tangential component 푟푒푠푝.푛표푟푚푎푙 푐표푚푝표푛푒푛푡 of ∅푁. For almost contact structure the Nijenhuis tensor 푁 푋,푌 is expressed as 푁 푋,푌 = 훻 ∅푋∅ 푌− 훻 ∅푌∅ 푋−∅ 훻 푋∅ 푌+∅ 훻 푌∅ 푋 (2.16) Now from (2.9),replacing 푋 by ∅푋, we have ∇ ∅푋∅ 푌=− 휂 푌 푋−휂 푋 휂 푌 휉− ∇ 푌∅ ∅푋. (2.17) Differentiating (2.1) conveniently along the vector and using (2.10), we have ∇ 푌∅ ∅푋= ∇ 푌휂 푋 휉−∅ ∇ 푌∅ 푋. (2.18) From (2.17) and (2.18), we have ∇ ∅푋∅ 푌=−휂 푌 푋−휂 푋 휂 푌 휉− ∇ 푌휂 푋 휉+∅ ∇ 푌∅ 푋. (2.19) Interchanging 푋and 푌, we have ∇ ∅푌∅ 푋=− 휂 푋 푌−휂 푋 휂 푌 휉− ∇ 푋휂 푌 휉+∅ ∇ 푋∅ 푌. (2.20) Using equation (2.19), (2.20) and (2.9) in (2.16), we have 푁 푋,푌 =휂 푋 푌− 휂 푌 푋+2푑휂 푋,푌 휉+2∅ ∇ 푌∅ 푋−2∅ ∇ 푋∅ 푌, (2.21) 푁 푋,푌 =2푔 ∅푋,푌 휉+5휂 푋 푌+3휂 푌 푋+8휂 푋 휂 푌 휉+4∅ ∇ 푌∅ 푋. (2.22) As we know that, ∇ 푌∅ 푋=∇ 푌∅푋−∅ ∇ 푌푋 .UsingGuass formula (2.11), we have ∅ ∇ 푌∅ 푋=∅ ∇푌∅푋 +∅푕 푌,∅푋 −∇푌푋−휂 ∇푌푋 휉−푕 푌,푋 . Using this equation in (2.22), we have 푁 푋,푌 =2푔 ∅푋,푌 휉+5휂 푋 푌+3휂 푌 푋+8휂 푋 휂 푌 휉+4∅ ∇푌∅푋 +4∅푕 푌,∅푋 −4 ∇푌푋 −4휂 ∇푌푋 휉−4푕 푌,푋 . (2.23)
III. Semi-invariant Submanifold
Let 푀 be submanifold immersed in 푀 , we assume that the vector 휉 is tangent to 푀, denoted by {휉} the 1- dimentional distribution spanned by 휉 on 푀, then 푀 is called a semi-invariant submanifold [9] of 푀 if there exist two differentiable distribution 퐷 &퐷 on 푀 satisfying (i) 푇푀= 퐷⨁퐷⨁휉 , where 퐷 ,퐷& 휉 are mutually orthogonal to each other, (ii) the distribution퐷 is invariant under ∅that is ∅퐷푥= 퐷푥 for all 푥 ∈ 푀, (iii) the distribution퐷is anti-invariant under ∅, that is ∅퐷푥 ⊂푇푀 for all푥 ∈ 푀,where 푇푀 & 푇푀 be the Lie algebra of vector fields tangential & normal to 푀 respectively. Theorem 3.1.The connection induced on semi-invariant submanifold of nearly hyperbolic Kenmotsu manifold with semi-symmetric metric connection also semi-symmetric metric.
4. TOUKEER KHANet al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 4, Issue 9( Version 3), September 2014, pp.61-69
www.ijera.com 64|P a g e
Proof:Let ∇be induced connection with respect to the normal 푁 on semi-invariant submanifold of nearly hyperbolic Kenmotsu manifold with semi-symmetric metricconnection ∇ , then ∇ 푋푌=∇푋푌+푚 푋,푌 , (3.1) where m is the tensor filed of type (0,2) on semi-invariant submanifold 푀. If ∇∗ be the induced connection on semi-invariant submanifold from Riemannian connection ∇ ,then ∇ 푋푌=∇푋∗ 푌+푕 푋,푌 , (3.2) where푕 is second fundamental tensor and we know that semi-symmetric metric connection on nearly hyperbolic Kenmotsu manifold ∇ 푋푌=∇ 푋푌+ 푌 푋−푔 푋,푌 휉. (3.3) Using (3.1), (3.2) in (3.3), we have ∇푋푌+푚 푋,푌 =∇푋∗ 푌+푕 푋,푌 +휂 푌 푋−푔 푋,푌 휉. (3.4) Comparing tangent and normal parts, we have ∇푋푌=∇푋∗ 푌+휂 푌 푋−푔 푋,푌 휉, 푚 푋,푌 =푕 푋,푌 . Thus ∇ is also semi-symmetric metric connection. Lemma 3.2. Let 푀 be a semi-invariant submanifold of a nearly hyperbolic Kenmotsu manifold 푀 with semi- symmetric metric connection, then 2 ∇ 푋∅ 푌=∇푋∅푌−∇푌∅푋+푕 푋,∅푌 −푕 푌,∅푋 −∅ 푋,푌 for each 푋,푌∈퐷. Proof.By Gauss formula (2.11), we have ∇ 푋∅푌−∇ 푌∅푋=∇푋∅푌−∇푌∅푋+푕 푋,∅푌 −푕 푌,∅푋 . (3.5) Also, by covariantly differentiation, we know that ∇ 푋∅푌−∇ 푌∅푋= ∇ 푋∅ 푌− ∇ 푌∅ 푋+∅ 푋,푌 . (3.6) From (3.5) and (3.6), we have ∇ 푋∅ 푌− ∇ 푌∅ 푋=∇푋∅푌−∇푌∅푋+푕 푋,∅푌 −푕 푌,∅푋 −∅ 푋,푌 . (3.7) Adding (2.9) and (3.7), we obtain 2 ∇ 푋∅ 푌=∇푋∅푌−∇푌∅푋+푕 푋,∅푌 −푕 푌,∅푋 −∅ 푋,푌 for each 푋,푌∈퐷. Lemma 3.3. Let 푀 be a semi-invariant submanifold of a nearly hyperbolic Kenmotsu manifold 푀 with semi- symmetric metric connection, then 2 ∇ 푌∅ 푋=∇푌∅푋−∇푋∅푌+푕 푌,∅푋 −푕 푋,∅푌 +∅ 푋,푌 for each 푋,푌∈퐷. Theorem 3.4. Let 푀 be a semi-invariant submanifold of a nearly hyperbolic Kenmotsu manifold 푀 with semi- symmetric metric connection, then 2 ∇ 푋∅ 푌=−퐴∅푌푋+∇푋 ⊥∅푌−∇푌∅푋−푕 푌,∅푋 −∅ 푋,푌 for all X∈퐷 푎푛푑 푌∈퐷⊥. Proof.By Gauss formulas (2.11), we have ∇ 푌∅푋=∇푌∅푋+푕 푌,∅푋 .
5. TOUKEER KHANet al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 4, Issue 9( Version 3), September 2014, pp.61-69
www.ijera.com 65|P a g e
Also, by Weingarten formula (2.12), we have ∇ 푋∅푌=−퐴∅푌푋+∇푋 ⊥∅푌. From abovetwo equations, we have ∇ 푋∅푌−∇ 푌∅푋=−퐴∅푌푋+∇푋 ⊥∅푌−∇푌∅푋−푕 푌,∅푋 . (3.8) Comparing equation (3.6) and (3.8), we have ∇ 푋∅ 푌− ∇ 푌∅ 푋=−퐴∅푌푋+∇푋 ⊥∅푌−∇푌∅푋−푕 푌,∅푋 −∅ 푋,푌 . (3.9) Adding equation (2.9) in (3.9), we have 2 ∇ 푋∅ 푌=−퐴∅푌푋+∇푋 ⊥∅푌−휂 푋 푌−∇푌∅푋−푕 푌,∅푋 −∅ 푋,푌 −2휂 푋 ∅푌−2휂 푌 ∅푋 2 ∇ 푋∅ 푌=−퐴∅푌푋+∇푋 ⊥∅푌−∇푌∅푋−푕 푌,∅푋 −∅ 푋,푌 for all 푋∈퐷 and 푌∈퐷⊥. Lemma 3.5. Let 푀 be a semi-invariant submanifold of a nearly hyperbolic Kenmotsu manifold 푀 with semi- symmetric metric connection, then 2 ∇ 푌∅ 푋=퐴∅푌푋−∇푋 ⊥∅푌+∇푌∅푋+푕 푌,∅푋 +∅ 푋,푌 (3.10) for all푋∈퐷 and 푌∈퐷⊥. Lemma 3.6. Let 푀 be a semi-invariant submanifold of a nearly hyperbolic Kenmotsu manifold 푀 with semi- symmetric metric connection, then 2 ∇ 푋∅ 푌=퐴∅푋푌−퐴∅푌푋+∇푋 ⊥∅푌−∇푌 ⊥∅푋−∅ 푋,푌 (3.11) for all 푋,푌∈퐷⊥. Proof.Using Weingarten formula (2.12), we have ∇ 푋∅푌−∇ 푌∅푋=퐴∅푋푌−퐴∅푌푋+∇푋 ⊥∅푌−∇푌 ⊥∅푋. Using equation (3.6) in above, we have ∇ 푋∅ 푌− ∇ 푌∅ 푋=퐴∅푋푌−퐴∅푌푋+∇푋 ⊥∅푌−∇푌 ⊥∅푋−∅ 푋,푌 . (3.12) Adding (2.9) in above, we have 2 ∇ 푋∅ 푌=퐴∅푋푌−퐴∅푌푋+∇푋 ⊥∅푌−∇푌 ⊥∅푋−∅ 푋,푌 for all 푋,푌∈퐷⊥. Lemma 3.7. Let 푀 be a semi-invariant submanifold of a nearly hyperbolic Kenmotsu manifold 푀 with semi- symmetric metric connection, then 2 ∇ 푌∅ 푋=퐴∅푌푋−퐴∅푋푌+∇푌 ⊥∅푋−∇푋 ⊥∅푌+∅ 푋,푌 for all푋,푌∈퐷⊥ Lemma 3.8. Let 푀 be a semi-invariant submanifold of a nearly hyperbolic Kenmotsu manifold 푀 with semi- symmetric metricconnection.Then 푃 ∇푋∅푃푌 +푃 ∇푌∅푃푋 −푃퐴∅푄푌푋−푃퐴∅푄푋푌=∅푃 ∇푋푌 +∅푃 ∇푌푋 −2휂 푋 ∅푃푌−2휂 푌 ∅푃푋, (3.13) 푄 ∇푋∅푃푌 +푄 ∇푌∅푃푋 −푄퐴∅푄푌푋−푄퐴∅푄푋푌=2퐵푕 푋,푌 , (3.14) 푕 푌,∅푃푋 +푕 푋,∅푃푌 +∇푋 ⊥∅푄푌+∇푌 ⊥∅푄푋=∅푄 ∇푋푌 +∅푄 ∇푌푋 +2퐶푕 푋,푌 −2휂 푋 ∅푄푌−2휂 푌 ∅푄푋, (3.15) 휂 ∇푋∅푃푌 +휂 ∇푌∅푃푋 −휂 퐴∅푄푌푋 −휂 퐴∅푄푋푌 =0 (3.16) for all 푋,푌∈푇푀.
6. TOUKEER KHANet al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 4, Issue 9( Version 3), September 2014, pp.61-69
www.ijera.com 66|P a g e
Proof.Differentiating covariantlyequation (2.14) and using equation (2.11) and(2.12), we have ∇ 푋∅ 푌+∅(∇푋푌)+∅푕 푋,푌 =∇푋∅푃푌+푕 푋,∅푃푌 −퐴∅푄푌푋+∇푋 ⊥∅푄푌. Interchanging 푋and 푌, we have ∇ 푌∅ 푋+∅(∇푌푋)+∅푕 푌,푋 =∇푌∅푃푋+푕 푌,∅푃푋 −퐴∅푄푋푌+∇푌 ⊥∅푄푋. Adding above two equations, we have ∇ 푋∅ 푌+ ∇ 푌∅ 푋+∅(∇푋푌)+∅(∇푌푋)+2∅푕 푋,푌 =∇푋∅푃푌+∇푌∅푃푋 +푕 푋,∅푃푌 +푕 푌,∅푃푋 −퐴∅푄푌푋−퐴∅푄푋푌+∇푋 ⊥∅푄푌+∇푌 ⊥∅푄푋. Using equation (2.9) in above, we have −2휂 푋 ∅푌–2휂 푌 ∅푋+∅(∇푋푌)+∅(∇푌푋)+2∅푕 푋,푌 =∇푋∅푃푌+∇푌∅푃푋 +푕 푋,∅푃푌 +푕 푌,∅푃푋 −퐴∅푄푌푋−퐴∅푄푋푌+∇푋 ⊥∅푄푌+∇푌 ⊥∅푄푋. Using equations (2.14), (2.15)&(2.2), we have −2휂 푋 ∅푃푌−2휂 푋 ∅푄푌−2휂 푌 ∅푃푋−2휂 푌 ∅푄푋+∅푃 ∇푋푌 +∅푄 ∇푋푌 +∅푃 ∇푌푋 +∅푄 ∇푌푋 +2퐵푕 푋,푌 +2퐶푕 푋,푌 =푃 ∇푋∅푃푌 +푄 ∇푋∅푃푌 +휂 ∇푋∅푃푌 휉+푃 ∇푌∅푃푋 +푄 ∇푌∅푃푋 +휂 ∇푌∅푃푋 휉+푕 푋,∅푃푌 +푕 푌,∅푃푋 −푃퐴∅푄푌푋−푄퐴∅푄푌푋−휂 퐴∅푄푌푋 휉−푃퐴∅푄푋푌−푄퐴∅푄푋푌 −휂 퐴∅푄푋푌 휉+∇푋 ⊥∅푄푌+∇푌 ⊥∅푄푋. Comparing horizontal, vertical and normal components we get desired results. ⊡
IV. Integrability of Distributions
Theorem4.1. Let 푀 be a semi-invariant submanifold of a nearly hyperbolic Kenmotsu manifold 푀 with semi- symmetric metric connection, then the distribution 퐷⨁ 휉 is integrable if the following conditions are satisfied 푆 푋,푌 ∈ 퐷⨁ 휉 (4.1) 푕 푋,∅푌 =푕 ∅푋,푌 (4.2) for each 푋,푌∈ 퐷⨁ 휉 . Proof.The torsion tensor 푆 푋,푌 of an almost hyperbolic contact manifold is given by 푆 푋,푌 =푁 푋,푌 +2푑휂 푋,푌 휉, where 푁 푋,푌 is Neijenhuis tensor, 푆 푋,푌 = ∅푋,∅푌 −∅ ∅푋,푌 −∅ 푋,∅푌 +2푑휂 푋,푌 휉. (4.3) Suppose that 퐷⨁ 휉 is integrable, then푁 푋,푌 =0for any 푋,푌∈ 퐷⨁ 휉 . Therefore, 푆 푋,푌 =2푑휂 푋,푌 휉∈ 퐷⨁ 휉 . From (4.3), (2.23) and comparing normal part, we have ∅푄 ∇푌∅푋 +퐶푕 푌,∅푋 −푕 푋,푌 =0 for 푋,푌∈ 퐷⨁ 휉 . Replacing푌 푏푦 ∅푍,where 푍∈퐷, ∅푄 ∇∅푍∅푋 +퐶푕 ∅푍,∅푋 −푕 푋,∅푍 =0. (4.4) Interchanging 푋 and 푍, we have ∅푄 ∇∅푋∅푍 +퐶푕 ∅푋,∅푍 −푕 푍,∅푋 =0. (4.5)
7. TOUKEER KHANet al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 4, Issue 9( Version 3), September 2014, pp.61-69
www.ijera.com 67|P a g e
Subtracting (4.4) from (4.5), we obtain ∅푄 ∅푋,∅푍 +푕 푋,∅푍 −푕 푍,∅푋 =0. Since 퐷⨁ 휉 is integrable so that ∅푋,∅푍 ∈ 퐷⨁ 휉 for 푋,푌∈퐷. Consequently, above equation gives 푕 푋,∅푍 =푕 ∅푋,푍 . ⊡ Proposition 4.2.Let 푀 be a semi-invariant submanifold of a nearly hyperbolicKenmotsu manifold 푀 with semi- symmetric metricconnection, then 퐴∅푌푍−퐴∅푍푌= 13∅푃 푌,푍 for each 푌,푍∈퐷⊥. Proof.Let 푌,푍∈퐷⊥and 푋∈푇푀, from (2.13), we have
2푔 퐴∅푍푌,푋 =푔 푕 푌,푋 ,∅푍 +푔 푕 푋,푌 ,∅푍 . (4.6) Using (2.11) and (2.9) in (4.6), we have 2 푔 퐴∅푍푌,푋 =−푔 ∇푋∅푌,푍 −푔 ∇푌∅푋,푍)−푔(푕 푋,∅푌 +푕 푌,∅푋 ,푍 −2휂 푋 푔 ∅푌,푍 −2휂 푌 푔 ∅푋,푍 . (4.7) From (2.12) and (4.7), we have 2푔 퐴∅푍푌,푋 =−푔 ∅∇푌푍,푋 +푔 퐴∅푌푍,푋 . Transvecting푋 from both sides, we obtain 2퐴∅푍푌=−∅∇푌푍+퐴∅푌푍. (4.8) Interchanging푌 and 푍, we have 2퐴∅푌푍=−∅∇푍푌+퐴∅푍푌. (4.9) Subtracting(4.8) from (4.9), we have 퐴∅푌푍−퐴∅푍푌 = 13∅푃 푌,푍 . (4.10) Theorem4.3.Let 푀 be a semi-invariant submanifold of a nearly hyperbolic Kenmotsu manifold 푀 with semi- symmetric metric connection, then the distribution is integrable if and only if 퐴∅푌푍−퐴∅푍푌=0 (4.11) for all 푌,푍∈퐷⊥. Proof.Suppose that the distribution 퐷⊥ is integrable, that is 푌,푍 ∈퐷⊥. Therefore, 푃 푌,푍 =0 for any 푌,푍∈ 퐷⊥. Consequently, from (4.10) we have 퐴∅푌푍−퐴∅푍푌=0. Conversely, let (4.11) holds. Then by virtue of (4.10), we have either 푃 푌,푍 =0 or 푃 푌,푍 =푘휉.But푃 푌,푍 = 푘휉is not possible as 푃 being a projection operator on 퐷.So,푃 푌,푍 =0.This implies that 푌,푍 ∈퐷⊥for all 푌,푍∈퐷⊥. Hence 퐷⊥ is integrable.
V. Parallel Distribution
8. TOUKEER KHANet al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 4, Issue 9( Version 3), September 2014, pp.61-69
www.ijera.com 68|P a g e
Definition 5.1.The horizontal (resp., vertical) distribution 퐷(푟푒푠푝.,퐷⊥) is said to be parallel [7] with respect to the connection on 푀 푖푓 ∇푋푌∈퐷 (푟푒푠푝.,∇푍푊∈퐷⊥) for any vector field. Proposition 5.2.Let 푀 be a semi-invariant submanifold of a nearly hyperbolicKenmotsu manifold 푀 with semi- symmetric metric connection. If the horizontal distribution 퐷 is parallel then푕 푋,∅푌 =푕 푌,∅푋 for all푋,푌∈ 퐷. Proof.Let푋,푌∈퐷, as퐷 is parallel distribution.So that ∇푋∅푌∈퐷and∇푌∅푋∈퐷. Now, from (3.14) and (3.15), we have 푄 ∇푋∅푃푌 +푄 ∇푌∅푃푋 −푄퐴∅푄푌푋−푄퐴∅푄푋푌+푕 푌,∅푃푋 +푕 푋,∅푃푌 +∇푋 ⊥∅푄푌+∇푌 ⊥∅푄푋=2퐵푕 푋,푌 +∅푄 ∇푋푌 +∅푄 ∇푌푋 +2퐶푕 푋,푌 −2휂 푋 ∅푄푌−2휂 푌 ∅푄푋. As푄 being a projection operator on 퐷⊥, then we have 푕 푋,∅푃푌 +푕 푌,∅푃푋 =2퐵푕 푋,푌 +2퐶푕 푋,푌 . Using (2.14) and (2.15) in above, we have 푕 푋,∅푌 +푕 푌,∅푋 =2∅푕 푋,푌 . (5.1) Replacing푋 푏푦 ∅푋 in (5.1) and using (2.1), we have 푕 ∅푋,∅푌 +푕 푌,푋 =2∅푕 ∅푋,푌 . (5.2) Replacing푌 푏푦 ∅푌 in (5.1) and using (2.1), we have 푕 푋,푌 +푕 ∅푌,∅푋 =2∅푕 푋,∅푌 . (5.3) Comparing (5.2) and (5.3), we get 푕 푋,∅푌 =푕 푌,∅푋 for all푋,푌∈퐷. Definition 5.3.A Semi-invariant submanifold is said to be mixed totally geodesic if 푕 푋,푌 =0 for all푋∈ 퐷 and 푌∈퐷⊥. Proposition 5.4.Let 푀 be a semi-invariant submanifold of a nearly hyperbolicKenmotsu manifold 푀 with semi- symmetric metric connection. Then 푀 is a mixed totally geodesic if and only if 퐴푁푋∈퐷 푓표푟 푎푙푙 푋∈퐷. Proof.Let 퐴푁푋∈퐷 for all푋∈퐷. Now, 푔 푕 푋,푌 ,푁 =푔 퐴푁푋,푌 =0 푓표푟 푌∈퐷⊥, which is equivalent to 푕 푋,푌 =0. Hence 푀 is totally mixed geodesic. Conversely, let 푀 is totally mixed geodesic.That is 푕 푋,푌 =0 푓표푟 푋∈퐷 and 푌∈퐷⊥. Now, from푔 푕 푋,푌 ,푁 =푔 퐴푁푋,푌 , we get 푔 퐴푁푋,푌 =0. That is퐴푁푋∈퐷 for all 푌∈퐷⊥. References [1] Agashe N. S. and Chafle M. R., A semi-symmetric non-metric connection in a Riemannian manifold, Indian J. Pure Applied Math., 23 (1992), 399-409. [2] M. Ahmad, K. Ali, Semi-invariant submanifolds of a nearly hyperbolic Kenmotsu manifold with semi- symmetric non-metric connection, International J. of Math. Sci. &Engg.Appls.(IJMSEA), Vol. 7 No.IV(July, 2013), pp. 107-119. [3] Ahmad M. and Jun J. B., On semi-invariant submanifolds of a nearly Kenmotsu Manifold with semi- symmetric non-metric connection, Journal of the Chungcheong Math. Soc., 23(2) (June 2010), 257-266.
9. TOUKEER KHANet al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 4, Issue 9( Version 3), September 2014, pp.61-69
www.ijera.com 69|P a g e
[4] Ahmad M., Jun J. B. and Siddiqi M. D., Some properties of semi-invariant submanifolds of a nearly trans-Sasakian manifold admitting a quarter symmetric non-metric connection, JCCMS, 25(1) (2012), 73-90. [5] Ahmad M. and Siddiqi M. D., On nearly Sasakian manifold with a semi-symmetric semi-metric connection, Int. J. Math. Analysis, 4(35) (2010), 1725-1732. [6] Ahmad M. and Siddiqi M. D., Semi-invariant submanifolds of Kenmotsu manifold immersed in a generalized almost r-contact structure admitting quarter symmetric non-metric connection, Journ. Math.Comput. Sci., 2(4) (2012),982-998. [7] D.E. Blair, Contact manifolds in Riemannian Geometry, Lecture Notes in Mathematics, Vol. 509, Springer-Verlag, Berlin, 1976. [8] Bejancu A., CR- submanifolds of a Kaehler manifold. I, Proc. Amer. Math. Soc., 69 (1978), 135-142. [9] Geometry of CR- submanifolds, D. Reidel Publishing Company, Holland, (1986). [10] Bejancu A. and Papaghuic N., Semi-invariant submanifolds of a Sasakian manifold, An. St. Univ. Al. I. Cuza, Iasi, 27 (1981), 163-170. [11] Blair D. E., Contact manifolds in Riemannian geometry, Lecture Notes in Mathematics, Vol. 509, Springer-Verlag, Berlin, (1976). [12] Das Lovejoy S., Ahmad M. and Haseeb A., Semi-invariant submanifolds of a nearlySasakianmanifold endowed with a semi-symmetric non-metric connection, Journal of Applied Analysis,17(1) (2011), 119- 130. [13] Friedmann A. And Schouten J. A., Uber die Geometric der halbsymmetrischenUbertragung Math. Z., 21 (1924), 211-223. [14] Golab S., On semi-symmetric and quarter symmetric linear connections, Tensor (N.S.), 29(3) (1975), 249-254. [15] Joshi N. K. and Dube K. K., Semi-invariant submanifolds of an almost r-contact hyperbolic metric manifold, Demonstratio Math. 36 (2001), 135-143. [16] Matsumoto K., On contact CR-submanifolds of Sasakian manifold, Intern. J. Math. Sci., 6 (1983), 313- 326. [17] Shahid M. H., On semi-invariant submanifolds of a nearly Sasakian manifold, Indian J. Pure and Applied Math., 95(10) (1993), 571-580. [18] Upadhyay M. D. and Dube K. K., Almost contact hyperbolic -structure, Acta. Math. Acad. Scient. Hung. Tomus, 28 (1976), 1-4. [19] Yano K. And Kon M., Contact CR-submanifolds, Kodai Math. J., 5(1982), 238-252. [20] L. S. Das, R. Nivas, S. Ali, and M. Ahmad, Study of submanifolds immersed in a manifold with quarter- symmetric semi-metric connection, Tensor N. S. 65(2004), 250-260. [21] Golab, S., On semi-symmetric and quarter-symmetric linear connections, Tensor 29 (1975), 249-254. [22] Ahmad M. Rahman S. and Siddiqi M. D., Semi-invariant submanifolds of a Nearly Sasakian manifold endowed with a semi-symmetric metric connection, Bull. Allahabad Math. Soc., 25(1) (2010), 23-33.