Disformal transformation provides a map relating different scalar-tensor and vector-tensor theories gives access to powerful solution-generating method in modified gravity. In view of the vast family new solutions one can achieve, it is crucial design suitable tools guide their construction. this work, we address question by revisiting Petrov classification disformally constructed gravity theor...

The author investigates into the history of main military library Russian Empire. In mid 19-th century, General Staff Library became one largest book depositories in Russia. sets goal to review events related during period when F. Kruse and A. N. Petrov were heading institution. This was characterized by consistent collection development collaborations with historians, new trends expanding open...

We investigate an h-p version of the continuous Petrov-Galerkin method for the nonlinear Volterra functional integro-differential equations with vanishing delays. We derive h-p version a priori error estimates in the L-, Hand L-norms, which are completely explicit in the local discretization and regularity parameters. Numerical computations supporting the theoretical results are also presented.

Petrov constructed a diffusion process in the compact Kingman simplex whose unique stationary distribution is the two-parameter Poisson–Dirichlet distribution of Pitman and Yor. We show that the subset of the simplex comprising vectors whose coordinates sum to 1 is the natural state space for the process. In fact, the complementary set acts like an entrance boundary.