Type II universal spacetimes

Type II Einstein spacetimes in higher dimensions

This short note shows that many of the results derived by Pravda et al (Class. Quant. Grav. 24 4407-4428 ) for higher-dimensional Type D Einstein spacetimes can be generalized to all Einstein spacetimes admitting a multiple WAND; the main new result being the extension to include the Type II case. Examples of Type D Einstein spacetimes admitting non-geodesic multiple WANDs are given in all dime...

Spacetimes with Semantics (II)

Using Promise Theory as a calculus, I review how to define agency in a scalable way, for the purpose of understanding semantic spacetimes. By following simple scaling rules, replacing individual agents with ‘super-agents’ (sub-spaces), it is shown how agency can be scaled both dynamically and semantically. The notion of occupancy and tenancy, or how space is used and filled in different ways, i...

Spacetimes of Finite Type

On the Existence of Radiation Gauges in Petrov type II spacetimes

The radiation gauges used by Chrzanowski (his IRG/ORG) for metric reconstruction in the Kerr spacetime seem to be over-specified. Their specification consists of five conditions: four, which we treat here as valid gauge conditions, plus an additional condition on the trace of the metric perturbation. In this work, we utilize a newly developed form of the perturbed Einstein equations to establis...

Type II Fluid Solutions to Einstein’s Field Equations in N-Dimensional Spherical Spacetimes

A large class of Type II fluid solutions to Einstein field equations in Ndimensional spherical spacetimes is found, wich includes most of the known solutions. A family of the generalized collapsing Vaidya solutions with homothetic self-similarity, parametrized by a constant λ, is studied, and found that when λ > λc(N), the collapse always forms black holes, and when λ < λc(N), it always forms n...