Using Maple+ GRTensorII in teaching basics of general relativity and cosmology

CA Sporea, DN Vulcanov - arXiv preprint arXiv:1411.7969, 2014 - arxiv.org
In this article we propose some Maple procedures, for teaching purposes, to study the basics
of General Relativity (GR) and Cosmology. After presenting some features of GRTensorII, a …

On the de Sitter tardyons and tachyons

II Cotaescu - arXiv preprint arXiv:1508.05607, 2015 - arxiv.org
It is shown that on the de Sitter manifolds the tachyonic geodesics are restricted such that
the classical tachyons cannot exist on this manifold at any time. On the contrary, the theory of …