Graves and Nomizu investigated an indefinite version of the Cartan's result. Specifically, they obtained the conditions for all non-degenerate planes to have the same sectional curvature in the idefinite Riemanman manifold. In this paper we are to stu...
Graves and Nomizu investigated an indefinite version of the Cartan's result. Specifically, they obtained the conditions for all non-degenerate planes to have the same sectional curvature in the idefinite Riemanman manifold. In this paper we are to study the cosymplectic version of the results of Graves and Nomizu and characterize an indefinite cosymplectic space form.