Spacetimes with continuous linear isotropies I: spatial rotations
نویسندگان
چکیده
The weakest known criterion for local rotational symmetry (LRS) in spacetimes of Petrov type D is due to Goode and Wainwright (1986). Here it shown, using methods related the Cartan-Karlhede procedure, be equivalent spatial rotation invariance Riemann tensor its first derivatives. Conformally flat are similarly studied shown that almost all cases same ensures LRS. Only conformally accelerated perfect fluids three curvature derivatives required ensure LRS, showing Ellis's original condition case necessary as well sufficient.
منابع مشابه
Linear adiabatic dynamics generated by operators with continuous spectrum. I
We are interested in the asymptotic behavior of the solution to the Cauchy problem for the linear evolution equation iε∂tψ = A(t)ψ, A(t) = A0 + V (t), ψ(0) = ψ0, in the limit ε → 0. A case of special interest is when the operator A(t) has continuous spectrum and the initial data ψ0 is, in particular, an improper eigenfunction of the continuous spectrum of A(0). Under suitable assumptions on A(t...
متن کاملLinear instability of nonvacuum spacetimes.
We study the problem of linear instability in non-vacuum spacetimes. For vacuum spa.cetimes linear instability occurs when the spacetime has Killing vectors. In the non-vacuum case, one must prescribe how the sources are to vary. For one natural choice, we show that the signal for instability is the existence of Integral Constraint Vector fields. These vector fields lead, as in the vacuum case,...
متن کاملLinear Formulas in Continuous Logic
We prove that continuous sentences preserved by the ultramean construction (a generalization of the ultraproduct construction) are exactly those sentences which are approximated by linear sentences. Continuous sentences preserved by linear elementary equivalence are exactly those sentences which are approximated in the Riesz space generated by linear sentences. Also, characterizations for linea...
متن کاملProjection Quasicrystals I: Toral Rotations
We present a systematic treatment of the commutative and non-commutative topol-ogy of quasicrystal point patterns and tilings produced in nite dimensional Euclidean space by the projection or strip method. With no conditions on the projection plane and with a general acceptance domain only weakly constrained, we examine two sets of points constructed by the projection method, one a nite decorat...
متن کاملSIMULATING CONTINUOUS FUZZY SYSTEMS: I
In previous studies we first concentrated on utilizing crisp simulationto produce discrete event fuzzy systems simulations. Then we extendedthis research to the simulation of continuous fuzzy systems models. In this paperwe continue our study of continuous fuzzy systems using crisp continuoussimulation. Consider a crisp continuous system whose evolution depends ondifferential equations. Such a ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: General Relativity and Gravitation
سال: 2021
ISSN: ['0001-7701', '1572-9532']
DOI: https://doi.org/10.1007/s10714-021-02829-9