The two theories where Einstein has made his greatest contribution are the Theory of Relativity and the Quantum Theory. A remarkable year in the life and scientific development of Einstein is undoubtedly the year 1905, when Einstein in Bern formulated at the same time his theories of the photoelectric effect, Brownian motion and the theory of special relativity (as it came to be known later).
The decisive points in the scientific life of Einstein were the Boltzmann statistical significance of entropy, the Planck theory of thermal radiation and the works of Lorentz on electrodynamics.
In the present work we investigate the Dirac equation in two dimensions for free particles and we obtain sumluminal and superluminal velocities. Studying also the above equation with zero initial mass, for Caldirola-Montaldi (C.M.) and small-distance derivative (S.D.D.) model, we prove the existence of superluminal velocities.
In the present paper we investigage the isotopic and genotopic structure in the relativistic theory, via the theory of isominkowskian spaces. According to Santilli the central assumption is that motion of particles and electromagnetic waves within inhomogeneous and anisotropic physical media implies an alteration of space-time representable via isominkowski spaces. For the isotopic case we obtain an interaction maximal speed of propagation of causal signals which is  c (speed of light in vacuum). For the genotopic case we introduce the simple Lie-admissible complex time model in which the interaction speed is complex and leads to complex values of mass. Also by using the small-distance derivative model we obtain the Lie-admissible Wheeler - De Witt equation and new concepts concerning the connection between space-time and particles. Finally for the isotopic and genotopic causes we obtain the asymmetry of space-time and the inhomogeneity as well as the arrow of the cosmological time.