Abstract
LetN n (4c) be ann-dimensional complex space form of constant holomorphic sectional curvature 4c and letx:M n→N n (4c) be ann-dimensional Lagrangian submanifold inN n (4c). We prove that the following inequality always hold onM n:\(\left| {\bar \nabla h} \right|^2 \geqslant \frac{{3n^2 }}{{n + 2}}\left| {\nabla ^ \bot \vec H} \right|^2 \) whereh is the second fundamental form andH is the mean curvature of the submanifold. We classify all submanifolds which at every point realize the equality in the above inequality. As a direct consequence of our Theorem, we give, a new characterization of theWhitney spheres in a complex space form.
Similar content being viewed by others
References
V. Borrelli, B. Y. Chen and J. M. Morvan,Une caractérization géométrique la sphere de Whitney, Comptes Rendus de l'Académie des Sciences, Paris, Série I, Mathématique321 (1995), 1485–1490.
I. Castro, C. R. Montealegre and F. Urbano,Closed conformal vector fields and Lagrangian submanifolds in complex space forms, Pacific Journal of Mathematics199 (2001), 269–302.
I. Castro and F. Urbano,Lagrangian surfaces in the complex Euclidean plane with conformal Maslov form, The Tôhoku Mathematical Journal45 (1993), 565–582.
I. Castro and F. Urbano,Twistor holomorphic Lagrangian surfaces in the complex projective and hyperbolic planes, Annals of Global Analysis and Geometry13 (1995), 59–67.
B. Y. Chen,Jacobi's elliptic functions and Lagrangian immersions, Proceedings of the Royal Society of Edinburgh. Section A126 (1996), 687–704.
B. Y. Chen,Interaction of Legendre curves and Lagrangian submanifolds Israel Journal of Mathematics99 (1997), 69–108.
B. Y. Chen,Complex extensors and Lagrangian submanifolds in complex Euclidean spaces, The Tôhoku Mathematical Journal49 (1997), 277–297.
B. Y. Chen and K. Ogiue,On totally real submanifolds, Transactions of the American Mathematical Society193 (1974), 257–266.
B. Y. Chen and L. Vrancken,Lagrangian submanifolds satisfying a basic equality, Proceedings of the Cambridge Philosophical Society120 (1996), 291–307.
R. Harvey and H. B. Lawson,Calibrated geometries, Acta Mathematica148 (1982), 47–157.
G. Huisken,Flow by mean curvature of convex surfaces into spheres, Journal of Differential Geometry20 (1984), 237–266.
H. Li,Willmore surfaces in S n, Annals of Global Analysis and Geometry21 (2002), 203–213.
H. Li,Willmore submanifolds in a sphere, Mathematical Research Letters9 (2002), 771–790.
S. Montiel and F. Urbano,Isotropic totally real submanifolds, Mathematische Zeitschrift199 (1988), 55–60.
H. Naitoh,Totally real parallel submanifolds, Tokyo Journal of Mathematics4 (1981), 279–306.
H. Naitoh,Parallel submanifolds of complex space forms I, Nagoya Mathematical Journal90 (1983), 85–117;II, ibid Nagoya Mathematical Journal91 (1983), 119–149.
H. Naitoh and M. Takeuchi,Totally real submanifolds and symmetric bounded domain, Osaka Journal of Mathematics19 (1982), 717–731.
A. Ros and F. Urbano,Lagrangian submanifolds of C n with conformal Maslov form and the Whitney sphere, Journal of the Mathematical Society of Japan50 (1998), 203–226.
Author information
Authors and Affiliations
Corresponding author
Additional information
Partially supported by a research fellowship of the Alexander von Humboldt Stiftung.
Rights and permissions
About this article
Cite this article
Li, H., Vrancken, L. A basic inequality and new characterization of Whitney spheres in a complex space form. Isr. J. Math. 146, 223–242 (2005). https://doi.org/10.1007/BF02773534
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02773534