In a preceding article we presented a general relativistic treatment of the derivation of the Boltzmann equation. The four-momenta occurring in this formalism were all on-shell four-momenta, verifying the mass-shell restriction p2=m2c2. Due to this restriction, the resulting Boltzmann equation,...

This series of two articles aims at dissipating the rather dense haze existing in the present literature around the General Relativistic Boltzmann equation. In this first article, the general relativistic one-particle distribution function in phase space is defined as an average of delta...

A feed-forward neural net with adaptable synaptic weights and fixed, zero or non-zero threshold potentials is studied, in the presence of a global feedback signal that can only have two values, depending on whether the output of the network in reaction to its input is right or wrong.

A recurrent neural net is studied that learns a set of patterns {ξμ} in the presence of noise. The learning rule is of a Hebbian type. It is well-known that, if noise is absent during the learning process, the resulting final values of the weights wij correspond to what is usually referred to...

The one-particle distribution function is of importance both in non-relativistic and relativistic statistical physics. In the relativistic framework, the Lorentz-invariance is possibly its most fundamental property. The present article on the subject is a contrastive one: we review, discuss...

Homogeneous Bianchi type II models are studied for universes containing a viscous fluid and a large scale magnetic field. The present values of the magnetic field, the anisotropy in the microwave radiation background and the Hubble parameters are obtained by numerical integration of the Einstein...

Shear and volume viscosity of the cosmic fluid in the lepton era are calculated with the help of relativistic kinetic theory. The cosmic fluid is taken to be a mixture of neutrinos (νe, νμ, ντ), electrons (e-) and their antiparticles. The differential cross-sections are determined on the...

The six viscosity coefficients characterizing a magnetized pe- γ-plasma are calculated on the basis of relativistic kinetic theory.

General expressions are derived for the transport coefficients related to the vectorial transport phenomena in a plasma. As an example, the electrical conductivity of the cosmological fluid is calculated.

The complicated twelve-fold collision-integrals occurring in relativistic kinetic theory are reduced to sums of two-fold integrals which can easily be evaluated once the interactions of the particles of the system in question are specified.