Abstract
A space-like surface S immersed in a 4-dimensional Lorentzian manifold will be said to be umbilical along a direction N normal to S if the second fundamental form along N is proportional to the first fundamental form of S. In particular, S is pseudo-umbilical if it is umbilical along the mean curvature vector field H and (totally) umbilical if it is umbilical along all possible normal directions. The possibility that the surface be umbilical along the unique normal direction orthogonal to H—“ortho-umbilical” surface—is also considered. I prove that the necessary and sufficient condition for S to be umbilical along a normal direction is that two independent Weingarten operators (and, a fortiori, all of them) commute, or equivalently that the shape tensor be diagonalizable on S. The umbilical direction is then uniquely determined. This can be seen to be equivalent to a condition relating the normal curvature and the appropriate part of the Riemann tensor of the space time. In particular, for conformally flat space-times (including Lorentz space forms) the necessary and sufficient condition is that the normal curvature vanishes. Some further consequences are analyzed, and the extension of the main results to arbitrary signatures and higher dimensions is briefly discussed.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Notes
- 1.
There is a long-standing tradition among mathematicians who study submanifolds to use the opposite convention, that is, ∇ for the inherited connection and \(\bar{\nabla }\) for the background connection. I stress this point here in the hope that this will avoid any possible confusion.
- 2.
If one chooses, say, σ N to be the positive root of \(\sqrt{{\sigma }_{N }^{2}}\) then it may fail to be differentiable at points where the two eigenvalues of A N coincide, that is, at points where σ N = 0. Of course, one can always set an “initial” condition for G | x at any point on x ∈ S and then the differentiable solution for the vector field G is fixed. Nevertheless, this initial condition is arbitrary.
- 3.
Notice the sign convention, which may not coincide with the preferred one for everybody.
- 4.
Up to proportionality factors, this K coincides with K N if N is non-null. If N is null, then N can be chosen to be either ℓ or k, and K is − K k or \(-{K}_{\mathcal{l}}\), respectively.
References
Alías, L.J., Estudillo, F.J.M., Romero, A.: Spacelike submanifolds with parallel mean curvature in pseudo-Riemannian space forms. Tsukuba J. Math. 21, 169–179 (1997)
Andersson, L., Metzger, J.: The area of horizons and the trapped region. Commun. Math. Phys. 290, 941–972 (2009)
Andersson, L., Mars, M., Simon, W.: Local existence of dynamical and trapping horizons. Phys. Rev. Lett. 95, 111102 (2005)
Andersson, L., Mars, M., Simon, W.: Stability of marginally outer trapped surfaces and existence of marginally outer trapped tubes. Adv. Theor. Math. Phys. 12, 853–888 (2008)
Beem, J.K., Ehrlich, P.E., Easley, K.L.: Global Lorentzian geometry. In: Pure and Applied Math. vol. 202. Marcel Dekker, New York (1996)
Bektaş, M., Ergüt, M.: Compact space-like submanifolds with parallel mean curvature vector of a pseudo-Riemannian space. Acta Univ. Palack. Olomuc. Fac. Rerum Natur. Math. 38, 17–24 (1999)
Bray, H., Hayward, S., Mars, M., Simon, W.: Generalized inverse mean curvature flows in spacetime. Commun. Math. Phys. 272, 119–138 (2007)
Cabrerizo, J.L., Fernández, M., Gómez, J.S.: Isotropy and marginally trapped surfaces in a spacetime. Class. Quantum Grav. 27, 135005 (2010)
Cao, Xi-F.: Pseudo-umbilical spacelike submanifolds in the indefinite space form. Balkan J. Geom. Appl. 6, 117–121 (2001)
Carrasco, A., Mars, M.: Stability of marginally outer trapped surfaces and symmetries. Class. Quantum Grav. 26, 175002 (2009)
Chen, B.Y.: Geometry of Submanifolds. Marcel Dekker, New York (1973)
Chen, B.Y.: Pseudo-Riemannian Geometries, δ-Invariants, and Applications. World Scientific, Singapore (2011)
Chen, B.Y., Yano, K.: Submanifolds umbilical with respect to a non-parallel normal subbundle. Kōdai Math. Sem. Rep. 25, 289–296 (1973)
Chen, B.Y., Yano, K.: Umbilical submanifolds with respect to a nonparallel normal direction. J. Diff. Geom. 8, 589–597 (1973)
Cvetic, M., Gibbons, G.W., Pope, C.N.: More about Birkhoff’s Invariant and Thorne’s Hoop Conjecture for Horizons. Class. Quantum Grav. 28, 195001 (2011)
Decu, S., Haesen, S., Verstraelen, L.: Optimal inequalities characterising quasi-umbilical submanifolds. J. Inequal. Pure Appl. Math. 9(3), 79 (2008)
Dursun, U.: On Chen immersions into Lorentzian space forms with nonflat normal space. Publ. Math. Debrecen 57, 375–387 (2000)
Eisenhart, L.P., Riemannian Geometry. Princeton University Press, Princeton (1949)
Galloway, G.J., Senovilla, J.M.M.: Singularity theorems based on trapped submanifolds of arbitrary co-dimension. Class. Quantum Grav. 27, 152002 (2010)
Gibbons, G.W.: The isoperimetric and Bogomolny inequalities for black holes. In: Willmore, Y., Hitchin, H. (eds.) Global Riemannian Geometry, pp. 194–202. Ellis Horwood, Chichester (1984)
Gibbons, G.W.: Collapsing shells and the isoperimetric inequality for black holes. Class. Quantum Grav. 14, 2905–2915 (1997)
Haesen, S., Kowalczyk, D., Verstraelen, L.: On the extrinsic principal directions of Riemannian submanifolds. Note Mat. 29, 41–53 (2009)
Hawking, S.W., Ellis, G.F.R.: The large scale structure of space time. Cambridge Univ. Press, Cambridge (1973)
Hawking, S.W., Penrose, R.: The singularities of gravitational collapse and cosmology. Proc. Roy. Soc. London A 314, 529–548 (1970)
Houh, C.S.: On Chen surfaces in a Minkowski space time. J. Geom. 32, 40–50 (1988)
Hu, Y.J., Ji, Y.Q., Niu, D.Q.: Space-like pseudo-umbilical submanifolds with parallel mean curvature in de Sitter spaces. J. Ningxia Univ. Nat. Sci. Ed. 26, 121–124 (2005)
Kim, Y.H., Kim, Y.W.: Pseudo-umbilical surfaces in a pseudo-Riemannian sphere or a pseudo-hyperbolic space. J. Korean Math. Soc. 32, 151–160 (1995)
Khuri, M.: A note on the non-existence of generalized apparent horizons in Minkowski space. Class. Quantum Grav. 26, 078001 (2009)
Kriele, M.: Spacetime. Springer, Berlin (1999)
Mars, M.: Present status of the Penrose inequality. Class. Quantum Grav. 26, 193001 (2009)
Mars, M., Senovilla, J.M.M.: Trapped surfaces and symmetries. Class. Quantum Grav. 20, L293–L300 (2003)
Misner, C.W., Thorne, K.S., Wheeler, J.A.: Gravitation. W.H. Freeman and Co., New York (1973)
O’Neill, B.: Semi-Riemannian Geometry: With Applications to Relativity. Academic, New York (1983)
Ôtsuki, T.: Pseudo-umbilical submanifolds with M-index ≤ 1 in Euclidean spaces. Kōdai Math. Sem. Rep. 20, 296–304 (1968)
Penrose, R.: Gravitational collapse and space time singularities. Phys. Rev. Lett. 14, 57–59 (1965)
Penrose, R.: Techniques of Differential Topology in Relativity, Regional Conference Series in Applied Math. vol. 7. SIAM, Philadelphia (1972)
Penrose, R.: Naked singularities. Ann. N.Y. Acad. Sci. 224, 125 (1973)
Roşca, R.: Sur les variétés lorentziennes 2-dimensionnelles immergées pseudo-ombilicalement dans une variét relativiste. C. R. Acad. Sci. Paris Sr. A-B 274, A561–A564 (1972)
Roşca, R.: Varietatile bidimensionale dei spatiul Minkowski pentru care curburite lui Otsuki sint nule. St. cerc. Mat. 24, 133–141 (1972)
Roşca, R.: Sous-varietés pseudo-minimales et minimales d’une varieté pseudo-Riemannienne structure per une connexion spin-euclidienn. C. R. Ac. Sci. Paris (Serie A-B) 290, 331–333 (1980)
Rouxel, B.: A-submanifolds in Euclidean space. Kōdai Math. J. 4, 181–188 (1981)
Rouxel, B.: Sur les A-surfaces d’un espace-temps de Minkowski M 4. Riv. Mat. Univ. Parma 8, 309–315 (1982)
Schouten, J.A.: Ricci Calculus. Springer, Berlin (1954)
Senovilla, J.M.M.: Singularity theorems and their consequences. Gen. Rel. Grav. 30, 701–848 (1998)
Senovilla, J.M.M.: Classification of spacelike surfaces in spacetime. Class. Quantum Grav. 24, 3091–3124 (2007)
Senovilla, J.M.M.: A reformulation of the hoop conjecture. Europhys. Lett. 81, 20004 (2008)
Senovilla, J.M.M.: Trapped surfaces. Int. J. Mod. Phys. D 20, 2139–2168 (2011)
Song, W.D., Pan, X.Y.: Pseudo-umbilical spacelike submanifolds in de Sitter spaces. J. Math. Res. Exposition 26, 825–830 (2006)
Sun, H.: On spacelike submanifolds of a pseudo-Riemannian space form. Note Mat. 15, 215–224(1995)
Stephani, H., Kramer, D., MacCallum, M.A.H., Hoenselaers, C., Herlt, E.: Exact Solutions to Einstein’s Field Equations, 2nd edn. Cambridge University Press, Cambridge (2003)
Wald, R.M.: General Relativity. The University of Chicago Press, Chicago (1984)
Yano, K., Ishihara, S.: Pseudo-umbilical submanifolds of co-dimension 2. Kōdai. Math. Sem. Rep. 21, 365–382 (1969)
Acknowledgments
I thank Miguel Sánchez and the referees for some comments. Supported by grants FIS2010-15492 (MICINN), UFI 11/55 and GIU06/37 (UPV/EHU) and P09-FQM-4496 (J. Andalucía—FEDER).
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2012 Springer Science+Business Media New York
About this paper
Cite this paper
Senovilla, J.M.M. (2012). Umbilical-Type Surfaces in SpaceTime. In: Sánchez, M., Ortega, M., Romero, A. (eds) Recent Trends in Lorentzian Geometry. Springer Proceedings in Mathematics & Statistics, vol 26. Springer, New York, NY. https://doi.org/10.1007/978-1-4614-4897-6_3
Download citation
DOI: https://doi.org/10.1007/978-1-4614-4897-6_3
Published:
Publisher Name: Springer, New York, NY
Print ISBN: 978-1-4614-4896-9
Online ISBN: 978-1-4614-4897-6
eBook Packages: Mathematics and StatisticsMathematics and Statistics (R0)