RANDERS METRICS OF REVERSIBLE CURVATURE.

In this paper, we introduce the notions of R-reversibility and Ricci-reversibility. We prove that Randers metrics are R-reversible or Ricci-reversible if and only if they are R-quadratic or Ricci-quadratic, respectively. Besides, we discuss the properties of Ricci-or R-reversible Randers metrics which are also weakly Einsteinian, or Douglassian, or of scalar flag curvature. In particular, we determine the local structure of Randers metrics which are Ricci-reversible and locally projectively flat, and prove that an n(> 3)-dimensional Ricci-reversible Randers metric of non-zero scalar flag curvature is locally projectively flat. [ABSTRACT FROM AUTHOR]