The Dirac equation for massive free electrically neutral spin 1/2 particles in a gravitation field is considered. The secondary quantization procedure is applied to it and the Hilbert space of multiparticle quantum states is constructed. 1. The Dirac equation and its current. Let M be a space-time manifold. It is a four-dimensional orientable manifold equipped with a pseudo-EuclideanMinkowski-t...

Consider the following consistent Sylvester tensor equation[mathscr{X}times_1 A +mathscr{X}times_2 B+mathscr{X}times_3 C=mathscr{D},]where the matrices $A,B, C$ and the tensor $mathscr{D}$ are given and $mathscr{X}$ is the unknown tensor. The current paper concerns with examining a simple and neat framework for accelerating the speed of convergence of the gradient-based iterative algorithm and ...

When Einstein was thinking about the theory of general relativity based on the elimination of especial relativity constraints (especially the geometric relationship of space and time), he understood the first limitation of especial relativity is ignoring changes over time. Because in especial relativity, only the curvature of the space was considered. Therefore, tensor calculations should be to...

Upon applying Chamseddine’s noncommutative deformation of gravity we obtain the leading order noncommutative corrections to the Robertson-Walker metric tensor. We get an isotropic inhomogeneous metric tensor for a certain choice of the noncommutativity parameters. Moreover, the singularity of the commutative metric at t = 0 is replaced by a more involved space-time structure in the noncommutati...

This paper describes an approach to elastic modelling of human tissue based on the use of 3D solid active models active cubes [2] and a shape description based on the metric tensor in a solid. Active cubes are used because they provide a natural parameterization of the surface and the interior of the given object when deformed to match the object's shape. Using the metric tensor to store the sh...

Necessary and sufficient conditions for some deformation algebras to provide formal Frobenius structures are given. Also, examples of formal Frobenius structures with fundamental tensor that is not of the deformation type and examples of symmetric non-metric connections are presented. 2000 Math. Subject Classification: 53D45, 53C05, 53B15.

recognition of relationship between the present day stress state and fractures is very important in fractured reservoirs. fractures that are parallel or oblique to maximum horizontal stress have more tendencies to tensile deformation and tensile deformed fractures will be more permeable. the dalan formation is one of the main gas reservoirs of iran witch most of the production from this formati...

in this paper, the matsumoto metric with special ricci tensor has been investigated. it is proved that, if  is ofpositive (negative) sectional curvature and f is of  -parallel ricci curvature with constant killing 1-form ,then (m,f) is a riemannian einstein space. in fact, we generalize the riemannian result established by akbar-zadeh.