Given an N x N matrix, g a metric with lower indices; and x-, and N-vector (coordinates); EinsteinTensor[g,x] computes the Einstein tensor (an N x N matrix) with lower ...

We study the conditions under which a Kahlerian structure (G. J), of general natural lift type on the tangent bundle T M of a Riemannian manifold (M, g), studied in [S. ...

Given the coordinate N-vector and a metric (N x N matrix), the package defines "functions" which return the inverse metric, the Christoffel connection, the Riemann, Ricci and ...

Y.Euh, J. Park and K. Sekigawa were the first authors who defined the concept of a weakly Einstein Riemannian manifold as a modification of that of an Einstein Riemannian ...

The Zebra Puzzle is a logical puzzle attributed to Einstein involving five men, all with different nationalities, jobs, pets, favorite drinks and living in houses of ...

Why is teaching general relativity so difficult? It's not only a theory of gravity; it is a theory of the structure of space and tiem, and hence a theory of the dynamics of ...

We analyze a four-dimensional induced Einstein-Kalb-Ramond theory with a conformally coupled Kalb-Ramond action. We also comment on an Ansatz which is inconsistent with the ...

We consider the Einstein equation with first-order (semiclassical) quantum corrections. Although the quantum corrections contain up to fourth-order derivatives of the metric, ...

This package introduces definitions for tensor calculations in Riemannian Geometry. To begin a calculation the user must specify a Riemannian space by giving: a list of ...

We present a suite of Mathematica-based computer-algebra packages, termed "Kranc", which comprise a toolbox to convert certain (tensorial) systems of partial differential ...