Results 41 to 50 of about 7,610 (173)

Does the Isotropy of the CMB Imply a Homogeneous Universe? Some Generalised EGS Theorems [PDF]

, 1999
We demonstrate that the high isotropy of the Cosmic Microwave Background (CMB), combined with the Copernican principle, is not sufficient to prove homogeneity of the universe -- in contrast to previous results on this subject.
, Barnes A, Barnes A, Barrett R K, Barrett R K, Bona C, Chris A Clarkson, Coley A A, Ehlers J, Ellis G F R, Ellis G F R, Krasinski A, MacCallum M A H, Nilsson U S, Peebles P J E, Richard K Barrett, Schmoldt I, Stephani H, Stephani H, Treciokas R, Willick J A   +20 more
core   +2 more sources

ELECTROMAGNETISM AND PERFECT FLUIDS INTERPLAY IN MULTIDIMENSIONAL SPACETIMES [PDF]

The Eleventh Marcel Grossmann Meeting, 2008
We consider fields in (D>2)-dimensional spacetime, whose potential is r-form (skew-symmetric tensor of rank r), the field tensor F being its exterior derivative and the Lagrangian, a function of the quadratic invariant I of this tensor. It is shown that vector field (r=1) describes electromagnetic field only for D=4.
openaire   +2 more sources

Properties of kinematic singularities [PDF]

, 2009
The locally rotationally symmetric tilted perfect fluid Bianchi type V cosmological model provides examples of future geodesically complete spacetimes that admit a `kinematic singularity' at which the fluid congruence is inextendible but all frame ...
Coley, A. A., Hervik, S., Lim, W. C., MacCallum, M. A. H.   +3 more
core   +1 more source

Kinematic Self-Similarity [PDF]

, 1996
Self-similarity in general relativity is briefly reviewed and the differences between self-similarity of the first kind and generalized self-similarity are discussed.
A A Coley, Barenblatt G I, Barenblatt G I, Benoit P M, Bertschinger E, Cahill A H, Carter B, Castejon-Amenedo J, Coley A A, Coley A A, Coley A A, Collins C B, Defrise-Carter L, Eardley D M, Ellis G F R, Henriksen R N, Hewitt C G, Hsu L, Kramer D, Lynden-Bell D, Maartens R, McIntosh C B G, Ponce de Leon J, Sedov L I, Stephani H, Tomita K, Tomita K, Wainwright J, Yano K   +28 more
core   +2 more sources

Conformal Ricci collineations of static spherically symmetric spacetimes

, 2010
Conformal Ricci collineations of static spherically symmetric spacetimes are studied. The general form of the vector fields generating conformal Ricci collineations is found when the Ricci tensor is non-degenerate, in which case the number of independent
Asghar Qadir, Bokhari A H, Camci U, Duggal K L, K Saifullah, Keane A J, Maartens R, Qadir A, Stephani H, Ugur Camci, Ziad M   +10 more
core   +1 more source

All Static Circularly Symmetric Perfect Fluid Solutions of 2+1 Gravity [PDF]

, 2002
Via a straightforward integration of the Einstein equations with cosmological constant, all static circularly symmetric perfect fluid 2+1 solutions are derived. The structural functions of the metric depend on the energy density, which remains in general
A. Staruszkiewicz, A.A. García, A.A. García, Alberto A. García, C. Martínez, C.D. Collinson, Cuauhtemoc Campuzano, E. Cotton, F. Kottler, G. Clement, J.D. Barrow, J.R. Gott, M. Cataldo, M. Cataldo, M. Cataldo, M. Cataldo, M. Gürses, M. Gürses, M. Kamata, N. Cruz, N.J. Cornish, P. Collas, R. C. Tolman, R. Emparan, S. Deser, S. Deser, S. Giddings   +26 more
core   +2 more sources

Systemic Governance From Below: Story Telling to Empower Access to the Commons Through Mapping and Modelling: A Mixed Methods Approach

Systems Research and Behavioral Science, EarlyView.
ABSTRACT Access to forests, farming land and the Citarum river is limited in Tarumajaya; furthermore, many do not own their own housing and are dependent on the public and private landowners in the area. The region of Tarumajaya faces significant challenges in access to crucial resources such as forests, farming land and the Citarum river, leading to a
Rudolf Wirawan, Janet Judy McIntyre‐Mills, R. Riswanda R. Riswanda, Ida Widianingsih, Indra Gunawan   +4 more
wiley   +1 more source

The covariant approach to LRS perfect fluid spacetime geometries [PDF]

Classical and Quantum Gravity, 1996
25 pages, uuencoded/compressed postscript ...
van Elst, Henk, Ellis, George F. R.
openaire   +2 more sources

Hypersurface homogeneous locally rotationally symmetric spacetimes admitting conformal symmetries

, 2003
All hypersurface homogeneous locally rotationally symmetric spacetimes which admit conformal symmetries are determined and the symmetry vectors are given explicitly. It is shown that these spacetimes must be considered in two sets.
Carot J, Choquet-Bruhat Y, Coley A A, Coley A A, Coley A A, Collins C B, Defrise-Carter L, Ellis G F R, Ellis G F R, Hall G S, Herrera L, Katzin G H, Katzin G H, Kitamura S, Kitamura S, Kramer D, Maartens R, Maartens R, Maartens R, Maartens R, MacCallum M A H, Marklund M, Marklund M, Michael Tsamparlis, Pantelis S Apostolopoulos, Rebouças M J, Sintes A M, Stewart J M, Tsamparlis M, Tupper B O J, van Elst H, Wainwright J   +31 more
core   +1 more source

Aggregation and the Structure of Value

Noûs, EarlyView.
ABSTRACT Roughly, the view I call “Additivism” sums up value across time and people. Given some standard assumptions, I show that Additivism follows from two principles. The first says that how lives align in time cannot, in itself, matter. The second says, roughly, that a world cannot be better unless it is better within some period or another.
Weng Kin San
wiley   +1 more source