Abstract
We study a generalization of K-contact and (k, μ)-contact manifolds, and show that if such manifolds of dimensions ≥ 5 are conformally flat, then they have constant curvature +1. We also show under certain conditions that such manifolds admitting a non-homothetic closed conformal vector field are isometric to a unit sphere. Finally, we show that such manifolds with parallel Ricci tensor are either Einstein, or of zero \({\xi}\)-sectional curvature.
Similar content being viewed by others
References
Bang, K.: Riemannian Geometry of Vector Bundles. Thesis, Michigan State University (1994)
Bang, K., Blair, D.E.: The schouten tensor and conformally flat manifolds. In: Topics in Differential Geometry, Ed. Acad. Romania , pp. 1–28 (2008)
Blair, D.E.: Riemannian geometry of contact and symplectic manifolds. Progress in Mathematics, vol. 203, Birkhauser, Basel (2010)
Blair D.E., Koufogiorgos T.: When is the tangent sphere bundle conformally flat? J. Geom. 49, 55–66 (1994)
Blair D.E., Koufogiorgos T., Papantoniou B.J.: Contact metric manifolds satisfying a nullity condition. Israel J. Math. 91, 189–214 (1995)
Blair D.E., Sharma R.: Generalization of Myers’ theorem on a contact mani fold. Ill. J. Math. 34, 837–844 (1990)
Blair, D.E., Sharma, R.: Three dimensional locally symmetric contact metric manifolds. Bolletino U.M.I. (7) 4-A, 385–390 (1990)
Boeckx E., Cho J.T.: η-parallel contact metric spaces. Differ. Geom. Appl. 22, 275–285 (2005)
Calvaruso G., Perrone D., Vanhecke L.: Homogeneity on three-dimensional contact metric manifolds. Isr. J. Math. 114, 301–321 (1999)
Ghosh A., Koufogiorgos T., Sharma R.: Conformally flat contact metric manifolds. J. Geom. 70, 66–76 (2001)
Ghosh A., Sharma R., Cho J.T.: Contact metric manifolds with η-parallel torsion tensor. Ann. Glob. Anal. Geom. 34, 287–299 (2008)
Goldberg S.I.: Curvature and Homology. Academic Press, New York (1962)
Gouli-Andreou F., Tsolakidou N.: On conformally flat contact metric manifolds. J. Geom. 79, 75–88 (2004)
Gouli-Andreou F., Tsolakidou N.: Conformally flat contact metric manifolds with \({Q\xi = \rho\xi}\). Beitrage Algebra Geom. 45, 103–115 (2004)
Obata M.: Certain conditions for a Riemannian manifold to be isometric with a sphere. J. Math. Soc. Japan 14, 333–340 (1962)
Okumura M.: Some remarks on space with a certain contact structure. Tohoku Math. J. 14, 135–145 (1962)
Okumura M.: On infinitesimal conformal and projective transformations of normal contact spaces. Tohoku Math. J. 14, 398–412 (1962)
Olszak Z.: On contact metric manifolds. Tohoku Math. J. 31, 247–253 (1979)
Perrone D.: Contact metric manifolds whose characteristic vector field is a harmonic vector field. Differ. Geom. Appl. 20, 367–378 (2004)
Ross A., Urbano F.: Lagrangian submanifolds of C n with conformal Maslov form and the Whitney sphere. J. Math. Soc. Japan 50, 203–226 (1998)
Sharma R.: Contact hypersurfaces of Kaehler manifolds. J. Geom. 78, 156–167 (2003)
Sharma, R., Blair, D.E.: Conformal motion of contact manifolds with charac teristic vector field in the k-nullity distribution. Ill. J. Math. 40, 553-563 (1996). Addendum: Ill. J. Math. 42, 673-677 (1998)
Sharma R., Vrancken L.: Conformal classification of (k, μ)-contact manifolds. Kodai Math. J. 33, 267–282 (2010)
Tanno S.: Some transformations on manifolds with almost contact and contact metric structures, II. Tohoku Math. J. 15, 322–331 (1963)
Tanno S.: Locally symmetric K-contact Riemannian manifolds. Proc. Japan Acad. 43, 581–583 (1967)
Tanno S.: Variational problems on contact Riemannian manifolds. Trans. Am. Math. Soc. 314, 349–379 (1989)
Yano K.: Integral Formulas in Riemannian Geometry. Marcel Dekker, New York (1970)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Ghosh, A., Sharma, R. A generalization of K-contact and (k, μ)-contact manifolds. J. Geom. 103, 431–443 (2012). https://doi.org/10.1007/s00022-013-0144-8
Received:
Revised:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00022-013-0144-8