Singularity editing of a quadrangle mesh consists in shifting singularities around for either improving the quality elements or canceling extraneous singularities, so as to increase regularity. However, particular structure quad renders exploration allowable connectivity changes non-local and hard automate. In this paper, we introduce simple, principled, general quad-mesh primitive with which p...

Global visibility of naked singularities is analyzed here for a class of spherically symmetric spacetimes, extending previous studies limited to inhomogeneous dust cloud collapse to more physical valid situations in which pressures are non-vanishing. Existence of nonradial geodesics escaping from the singularity is shown, and the observability of the singularity from far-away observers is discu...

We show that a singularity can occur at a finite future time in an expanding Friedmann universe even when ρ > 0 and ρ+ 3p > 0. Explicit examples are constructed and a simple condition is given which can be used to eliminate behaviour of this sort if it is judged to be unphysical. There have been many recent investigations into the theoretical possibility that expanding universes can come to a v...

Much of the published work regarding the Isotropic Singularity is performed under the assumption that the matter source for the cosmological model is a barotropic perfect fluid, or even a perfect fluid with a γ-law equation of state. There are, however, some general properties of cosmological models which admit an Isotropic Singularity, irrespective of the matter source. In particular, we show ...

As follows from Gott’s discovery, a pair of straight string-like singularities moving in opposite directions, when they have suitable speed and impact parameter, produce closed timelike curves. I argue this paper that there always is not-so-frightening alternative: the Universe may prefer to certain (surprisingly simple absolutely mild) singularity instead.

Fundamental theories of quantum gravity such as supergravity include a four form field strength which contributes to the cosmological constant. The inclusion of such a field into our theory of open inflation [1] solves the problem of the most likely universe being too empty. It also allows an anthropic solution to the cosmological constant problem in which cosmological constant gives a small bu...