Almost complex structure over almost contact metric structures

Document Type : Original Article

Author

Department of Mathematics, Tabriz Branch Islamic Azad University, Tabriz, Iran

Abstract

In this paper, we investigate the conditions under which a lifted almost complex structure ‎$‎J‎$‎ on the tangent bundle ‎$‎TM‎$‎ of a manifold ‎$‎M‎$‎ exhibits various Kählerian properties. We establish several characterizations relating the geometry of ‎$‎(TM, J)‎$‎ to the cosymplectic structure on ‎$‎M‎$‎. Specifically, we show that ‎$‎(TM, J)‎$‎ is Kählerian if and only if ‎$‎(M, \eta, \xi, \varphi)‎$‎ is cosymplectic and ‎$‎R = 0‎$‎. Similarly, we prove that ‎$‎(TM, J)‎$‎ is nearly Kählerian under the same conditions on ‎$‎M‎$‎. Furthermore, we present an alternative criterion for ‎$‎(TM, J)‎$‎ to be Kählerian, involving a nearly cosymplectic condition on ‎$‎M‎$‎ alongside a specific curvature relation. Finally, we demonstrate that ‎$‎(TM, J)‎$‎ is semi-Kählerian if and only if ‎$‎(M, \eta, \xi, \varphi)‎$‎ is semi-cosymplectic with ‎$‎R(X, Y) \varphi Z = 0‎$‎. These results reveal intricate connections between cosymplectic structures on ‎$‎M‎$‎ and Kählerian-type structures on ‎$‎TM‎$‎, contributing to the broader understanding of almost complex geometry on tangent bundles.

Keywords

Main Subjects