Authors: Wenceslao Segura González
Comments: 8 Pages.
This paper develops the uniqueness theorem of the curvature tensor, which states that the Riemann-Christoffel tensor (and its linear combinations) is the only tensor that depends on the connection and is linear with respect to the second derivatives of the metric tensor. From this result, Cartan's theorem is obtained, according to which Einstein's tensor is the only second-order tensor that depends on the metric tensor, on its first derivatives, is linear with respect to the second derivatives of the metric tensor and its covariant divergence is null, admitting that the coefficients of these second derivatives are tensors derived from the metric tensor.
Authors: Dante Servi
Comments: 14 Pages.
Analysis of the polygonal type resulting from the types with step (Pc) of the circles (Cs) manageable, foreseen in the list of types with angular step (C). The list is in sheet 8/14 of my article "How and why to use my graphic method" revision v4.
To find all my articles on this subject grouped in a single page, just click on author's name: Dante Servi.
Authors: Antoine Balan
Comments: 1 page, written in english
We define the Riemann metrics for riemannian manifolds.