Berwald geometries are Finsler close to (pseudo)-Riemannian geometries. We establish a simple first order partial differential equation as necessary and sufficient condition, which given Lagrangian has satisfy be of type. Applied $(\alpha,\beta)$-Finsler spaces, respectively $(A,B)$-Finsler spacetimes, this reduces condition for the Levi-Civita covariant derivative defining $1$-form. illustrate...

In this paper, an exact solution of Kerr black hole surrounded by a cloud strings in Rastall gravity is obtained Newman-Janis algorithm without complexification, and the influence string parameter $a_0$ on thermodynamics studied. Furthermore, according to solution, we investigate effect gravitational deflection massive particles. For receiver source at infinite distance from lens object, use os...

Abstract The main result of this paper is an expression the flag curvature a submanifold Randers–Minkowski space $$({\mathscr {V}},F)$$ ( V , F ) in terms invariants related to its Zermelo data ( h , W ). More precisely...