X iv : g r - qc / 9 81 10 53 v 1 1 7 N ov 1 99 8 The internal description of a causal set : What the universe looks like from the inside

ar X iv : g r - qc / 9 81 10 89 v 1 2 6 N ov 1 99 8 Spectral methods in general relativistic astrophysics

We present spectral methods developed in our group to solve three-dimensional partial differential equations. The emphasis is put on equations arising from astro-physical problems in the framework of general relativity.

ar X iv : g r - qc / 9 61 10 11 v 1 5 N ov 1 99 6 On Relation between String Theory and Multidimensional Cosmology

It is shown that a transition from a multidimensional cosmological model with one internal space of the dimension d 1 to the effective tree-level bosonic string corresponds to an infinite number of the internal dimensions: d 1 → ∞.

ar X iv : g r - qc / 9 51 10 48 v 1 1 6 N ov 1 99 5 Two lectures on Two - Dimensional Gravity ∗

ar X iv : g r - qc / 9 81 10 50 v 1 1 6 N ov 1 99 8 Are Decoherent Histories logically consistent ? Angelo

With reference to a particular example, we prove that the Decoherent Histories approach to Quantum Mechanics meets logical contradictions unless one drastically limits the allowed decoherent families. Our proof follows a line of reasoning different from the one of anologous criticisms which have been put forward recently; due to its different logical structure, it cannot be rejected on the basi...

ar X iv : g r - qc / 9 91 10 87 v 1 2 2 N ov 1 99 9 1 Eternal inflation and the present universe

Eternally inflating universes can contain thermalized regions with different values of the cosmological parameters. In particular, the spectra of density fluctuations should be different, because of the different realizations of quantum fluctuations of the inflaton field. I discuss a general method for calculating probability distributions for such variable parameters and analyze the density fl...