On a problem of Osserman in Lorentzian geometry

GarciaRio, E
Kupeli, DN
VazquezAbal, ME
A problem of Osserman on the constancy of the eigenvalues of the Jacobi operator is studied in Lorentzian geometry. Attention is paid to the different cases of timelike, spacelike and null Osserman condition. One also shows a relation between the null Osserman condition and a previous one on infinitesimal null isotropy.


BASKAL, S; ERIS, A; SATIR, A (1994-12-19)
The symmetries and associated conservation laws of the SO(2,1) invariant non-linear sigma model equations in 1+1 dimensions are investigated. An infinite family of generalized local symmetries is presented and the uniqueness of these solutions is discussed.
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We show that a closed, orientable 4-manifold M admits a Cayley-free embedding into flat Spin(7)-manifold R-8 if and only if both the Euler characteristic chi(M) and the signature tau(M) of M vanish.
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Demir, Ali Sait; Ozan, Yıldıray; Department of Mathematics (2008)
Let M be smooth symplectic closed manifold and L a closed Lagrangian submanifold of M. It was shown by Ozan that Ham(M,L): the relative Hamiltonian diffeomorphisms on M fixing the Lagrangian submanifold L setwise is a subgroup which is equal to the kernel of the restriction of the flux homomorphism to the universal cover of the identity component of the relative symplectomorphisms. In this thesis we show that Ham(M,L) is a non-simple perfect group, by adopting a technique due to Thurston, Herman, and Banyag...
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Diblík, J.; Zafer, A. (Hindawi Limited, 2011)
The stability of the zero solution of a system of first-order linear functional differential equations with nonconstant delay is considered. Sufficient conditions for stability, uniform stability, asymptotic stability, and uniform asymptotic stability are established.
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Let X-0 be a topological component of a nonsingular real algebraic variety and i : X --> X-C is a nonsingular projective complexification of X. In this paper, we will study the homomorphism on homotopy groups induced by the inclusion map i: X-0 --> X-C and obtain several results using rational homotopy theory and other standard tools of homotopy theory.
Citation Formats
E. GarciaRio, D. Kupeli, and M. VazquezAbal, “On a problem of Osserman in Lorentzian geometry,” DIFFERENTIAL GEOMETRY AND ITS APPLICATIONS, pp. 85–100, 1997, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/66749.