Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Demonstratio Mathematica

Powiadomienia systemowe

Sesja wygasła!

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: geometria Lorentziana

Sortuj według:

Ogranicz wyniki do:

On the geometric nature of the twin paradox in curved spacetimes

Sokołowski L. M.

Demonstratio Mathematica

2017

Vol. 50, nr 1

56--65

The famous „twin paradox” of special relativity is of purely geometric nature and formulated in curved spacetimes of general relativity motivates investigations of the timelike geodesic structure of these manifolds. Except for the maximally symmetric spacetimes the search for the longest timelike curves is hard, complicated and requires both advanced methods of global Lorentzian geometry and solving the intricate geodesic deviation equation. This article is a theoretical introduction to the problem. First we describe the procedure of determining the locally longest curves; it is algorithmic in the sense of consisting of a small number of definite steps and is effective if the geodesic deviation equation may be solved. Then we discuss the problem of globally maximal timelike curves; due to its nonlocal nature there is no prescription of how to solve it in finite number of steps. In the case of sufficiently high symmetry of the manifold also the globally longest curves may be found. Finally we briefly present some results recently found.

Submanifolds immersed in a generalized Hsu quaternion manifold

Das L., Nivas R., Mishra M.

Demonstratio Mathematica

2006

Vol. 39, nr 3

639-642

Integrability conditions of an almost quarternion manifold were studied by Yano and Ako [7]. Hamoui [1] and others have studied quaternion submanifolds of codimension 2 [1]. Vanzura [5] defined and have studied almost r- contact structure on manifolds. In this paper we have defined the Hsu-quaternion manifold and studied the submanifolds of codimension p immersed in a generalized Hsu quaternion manifold. Certain other interesting results have also been established.