Results 1 to 10 of about 63,399 (238)
Ricci Curvature Tensor-Based Volumetric Segmentation. [PDF]
Int J Comput VisAbstract Existing level set models employ regularization based only on gradient information, 1D curvature or 2D curvature. For 3D image segmentation, however, an appropriate curvature-based regularization should involve a well-defined 3D curvature energy. This is the first paper to introduce a regularization energy that incorporates 3D scalar
Huang J, Chen K, Alpers A, Lei N.
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The Simplicial Ricci Tensor [PDF]
Classical and Quantum Gravity, 2011 The Ricci tensor (Ric) is fundamental to Einstein's geometric theory of gravitation. The 3-dimensional Ric of a spacelike surface vanishes at the moment of time symmetry for vacuum spacetimes.
Bossavit A +23 more
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Conformal diffeomorphisms preserving the Ricci tensor [PDF]
Proceedings of the American Mathematical Society, 1995 We characterize semi-Riemannian manifolds admitting a global conformal transformation such that the difference of the two Ricci tensors is a constant multiple of the metric. Unless the conformal transformation is homothetic, the only possibilities are standard Riemannian spaces of constant sectional curvature and a particular warped product with a ...
Wolfgang Kühnel, Hans–Bert Rademacher
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Ricci Collineations for Non-Degenerate, Diagonal and Spherically Symmetric Ricci Tensors [PDF]
General Relativity and Gravitation, 1999 The expression of the vector field generator of a Ricci Collineation for diagonal, spherically symmetric and non-degenerate Ricci tensors is obtained.
A. H. Bokhari +11 more
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Indefinite Almost Paracontact Metric Manifolds [PDF]
International Journal of Mathematics and Mathematical Sciences, 2010 We introduce the concept of (ε)-almost paracontact manifolds, and in particular, of (ε)-para-Sasakian manifolds. Several examples are presented. Some typical identities for curvature tensor and Ricci tensor of (ε)-para Sasakian manifolds are obtained. We
Mukut Mani Tripathi +3 more
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Ricci tensor in graded geometry
Physics Letters B, 2020 We define the notion of the Ricci tensor for NQ symplectic manifolds of degree 2 and show that it corresponds to the standard generalized Ricci tensor on Courant algebroids.
Fridrich Valach
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Some Geometric Properties of the Bakry-Emery-Ricci Tensor [PDF]
, 2003 The Bakry-Emery tensor gives an analog of the Ricci tensor for a Riemannian manifold with a smooth measure. We show that some of the topological consequences of having a positive or nonnegative Ricci tensor are also valid for the Bakry-Emery tensor.
Lott, John
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Twistor spaces with Hermitian Ricci tensor [PDF]
Proceedings of the American Mathematical Society, 1990 The twistor space Z Z of an oriented Riemannian 4 4 -manifold M M admits a natural 1 1 -parameter family of Riemannian metrics h t {h_t} compatible with the almost-complex structures J 1
Johann Davidov, O. Muškarov
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Weyl structures with positive Ricci tensor [PDF]
Differential Geometry and its Applications, 1999 We prove the vanishing of the first Betti number on compact manifolds admitting a Weyl structure whose Ricci tensor satisfies certain positivity conditions, thus obtaining a Bochner-type vanishing theorem in Weyl geometry. We also study compact Hermitian-Weyl manifolds with non-negative symmetric part of the Ricci tensor of the canonical Weyl ...
Bogdan Alexandrov, Stefan Ivanov
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Evolution of the Weyl Tensor under the Ricci Flow [PDF]
, 2011 We compute the evolution equation of the Weyl tensor under the Ricci flow of a Riemannian manifold and we discuss some consequences for the classification of locally conformally flat Ricci ...
Catino, Giovanni, Mantegazza, Carlo
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