RELATIVISTIC UNIVERSES WITH SHEAR

Calculation of the relativistic bulk tensor and shear tensor of relativistic accretion flows in the Kerr metric.

In this paper, we calculate the relativistic bulk tensor and shear tensor of the relativistic accretion ows in the Kerr metric, overall and without any approximation. We obtain the relations of all components of the relativistic bulk and shear tensor in terms of components of four-velocity and its derivatives, Christoffel symbols and metric components in the BLF. Then, these components are deri...

Type Checking with Universes

Various formulations of constructive type theories have been proposed to serve as the basis for machine-assisted proof and as a theoretical basis for studying programming languages. Many of these calculi include a cumulative hierarchy of \universes," each a type of types closed under a collection of type-forming operations. Universes are of interest for a variety of reasons, some philosophical ...

Better Nonstandard Universes with Applications

Bouncing Universes with Varying Constants

We investigate the behaviour of exact closed bouncing Friedmann universes in theories with varying constants. We show that the simplest BSBM varying-alpha theory leads to a bouncing universe. The value of alpha increases monotonically, remaining approximately constant during most of each cycle, but increasing significantly around each bounce. When dissipation is introduced we show that in each ...

Spherical Universes with Anisotropic Pressure

Einstein’s equations are solved for spherically symmetric universes composed of dust with tangential pressure provided by angular momentum, L(R), which differs from shell to shell. The metric is given in terms of the shell label, R, and the proper time, τ , experienced by the dust particles. The general solution contains four arbitrary functions of R M(R), L(R), E(R) and τ0(R). The solution is ...