Results 1 to 10 of about 878,195 (332)
Null boundary phase space: slicings, news & memory [PDF]
Journal of High Energy Physics, 2021 We construct the boundary phase space in D-dimensional Einstein gravity with a generic given co-dimension one null surface N $$ \mathcal{N} $$ as the boundary.
H. Adami +5 more
doaj +3 more sources
Causal structure and degenerate phase boundaries [PDF]
, 1999 Timelike and null hypersurfaces in the degenerate space-times in the Ashtekar theory are defined in the light of the degenerate causal structure proposed by Matschull. Using the new definition of null hypersufaces, the conjecture that the "phase boundary"
A. Ashtekar +14 more
core +3 more sources
Involutes of Pseudo-Null Curves in Lorentz–Minkowski 3-Space
Mathematics, 2021 In this paper, we analyze involutes of pseudo-null curves in Lorentz–Minkowski 3-space. Pseudo-null curves are spacelike curves with null principal normals, and their involutes can be defined analogously as for the Euclidean curves, but they exhibit ...
Rafael López +3 more
doaj +1 more source
Research of face recognition based on null space kernel discriminant analysis
Gong-kuang zidonghua, 2013 In view of problem that method of null space linear discriminant analysis is difficult to reveal nonlinear structure of data of face image space, the paper proposed a method of null space kernel discriminant analysis. It introduced derivation process and
CHENG Ting-ting +2 more
doaj +1 more source
Intrinsic Geometry of a Null Hypersurface [PDF]
, 2000 We apply Cartan's method of equivalence to construct invariants of a given null hypersurface in a Lorentzian space-time. This enables us to fully classify the internal geometry of such surfaces and hence solve the local equivalence problem for null ...
Ashtekar A +8 more
core +2 more sources
A class of anisotropic (Finsler-) space-time geometries [PDF]
, 1997 A particular Finsler-metric proposed in [1,2] and describing a geometry with a preferred null direction is characterized here as belonging to a subclass contained in a larger class of Finsler-metrics with one or more preferred directions (null, space- or
G. Y. Bogoslovsky +7 more
core +2 more sources
The Effect of Sources on the Inner Horizon of Black Holes [PDF]
, 2001 Single pulse of null dust and colliding null dusts both transform a regular horizon into a space-like singularity in the space of colliding waves. The local isometry between such space-times and black holes extrapolates these results to the realm of ...
A. Ori +15 more
core +1 more source
The Eclipse-mapping Null Space: Comparing Theoretical Predictions with Observed Maps
The Astronomical Journal, 2023 High-precision exoplanet eclipse light curves, like those possible with JWST, enable flux and temperature mapping of exoplanet atmospheres. These eclipse maps will have unprecedented precision, providing an opportunity to constrain current theoretical ...
Ryan C. Challener, Emily Rauscher
doaj +1 more source
A condition for a perfect-fluid space-time to be a generalized Robertson-Walker space-time [PDF]
, 2016 A perfect-fluid space-time of dimension n>3 with 1) irrotational velocity vector field, 2) null divergence of the Weyl tensor, is a generalised Robertson-Walker space-time with Einstein fiber. Condition 1) is verified whenever pressure and energy density
De, Uday Chand +2 more
core +2 more sources
Twistor representation of null two-surfaces [PDF]
, 2001 We present a twistor description for null two-surfaces (null strings) in 4D Minkowski space-time. The Lagrangian density for a variational principle is taken as a surface-forming null bivector.
Ashtekar +26 more
core +2 more sources