In this paper we present a survey of Fermat metrics and their applications to stationary spacetimes. A principle for light rays is stated in class spacetimes variational theory the description multiple image effect. Some results on methods, as Ljusternik-Schnirelmann Morse Theory are recalled, give methods used. Other concern global hyperbolicity geodesic connectedeness characterization Sagnac ...

the purpose of this paper is to improve supply chain relationships in iranian small and medium-sized enterprises (smes) in automotive parts industry. for this reason, an importance-performance analysis (ipa) has been employed to categorized supply chain relationships metrics. also, the questionnaire method is used for gathering information. the paper identified thirteen supply chain relationshi...

equality of -curvatures of the berwald and cartan connections leads to a new class of finsler metrics, so-called bc-generalized landsberg metrics. here, we prove that every bc-generalized landsberg metric of scalar flag curvature with dimension greater than two is of constant flag curvature.