نتایج جستجو برای: lightlike submanifold

تعداد نتایج: 2207  

Journal: :Communications Faculty of Sciences University of Ankara. Series A1: mathematics and statistics 2023

The oriented angles between lightlike vectors cannot be defined properly compared to the timelike in Minkowski spacetime. Therefore, we use pseudo-angles any non-lightlike or develop theory of surfaces having constant angle with a fixed nonlightlike direction. We investigate some geometric properties on these such as being tangent developable. Besides, construct ruled by means null helices. giv...

2003
Dongsu Bak

We consider dimensional reduction of the lightlike holography of the covariant entropy bound from D + 1 dimensional geometry of M × S1 to the D dimensional geometry M . With a warping factor, the local Bekenstein bound in D+ 1 dimensions leads to a more refined form of the bound from the D dimensional view point. With this new local Bekenstein bound, it is quite possible to saturate the lightli...

1999
G. F. Chew

Massless elementary-particle propagation is represented historically (cosmologically) through 3-scale “towers of quartet rings” within a lattice of magneto-electrodynamically communicating “pre-events”. The lightlike intervals within a ring of 4 pre-events (discrete “closed string”) display transverse GUT-scale and longitudinal “particle scale”. The lightlike (longitudinal) spacing between succ...

In this paper, firstly, in $E_1^3$, we defined normal Fermi-Walker derivative and applied for the adapted frame. Normal Fermi-Walker parallelism, normal non-rotating frame, and Darboux vector expressions of normal Fermi-Walker derivative by normal Fermi-Walker derivative are given for adapted frame. Being conditions of normal Fermi-Walker derivative and normal non-rotating frame are examined fo...

Journal: :TURKISH JOURNAL OF MATHEMATICS 2014

Journal: :Int. J. Math. Mathematical Sciences 2006
Domenico Antonino Catalano

∇XV = λX for every vector field X. (1.2) Here ∇ denotes the Levi-Civita connection of g. We call vector fields satisfying (1.2) closed conformal vector fields. They appear in the work of Fialkow [3] about conformal geodesics, in the works of Yano [7–11] about concircular geometry in Riemannian manifolds, and in the works of Tashiro [6], Kerbrat [4], Kühnel and Rademacher [5], and many other aut...

2008
THOMAS KRANTZ

We investigate Kaluza-Klein metrics with a recurrent lightlike vector field over a pseudo-Riemannian manifold (B, g).

1993
P V Landshoff

We give a unified derivation of the propagator in the gauges n.A = 0 for n timelike, spacelike or lightlike. We discuss the physical states and other physical questions.

2008
Isabel Fernandez Francisco J. Lopez

We prove that the Lorentzian helicoid and Enneper’s surface are the unique properly embedded maximal surfaces bounded by a lightlike regular arc of mirror symmetry.

2009
Colin S Wallace

We show that the entropy created by Ohmic dissipation inside an accreting charged black hole may exceed the Bekenstein-Hawking entropy by a large factor. The second law of thermodynamics does not hold on spacelike slices inside these model black holes, even when the slices avoid Planck scale densities and curvatures. This result is distinct from, but consistent with, the fact that there is no e...

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