Invariant Submanifolds of Paracontact Metric ((kappa)over-tilde not equal-1, (mu)over-tilde)-Manifolds

Abstract

The principal objective of this paper is to answer positively the open question whether every invariant submanifold of a paracontact metric ((kappa) over tilde, (mu) over tilde)-manifold is totally geodesic. Main result is that any invariant submanifold of a paracontact metric ((kappa) over tilde, (mu) over tilde)-manifold, (kappa) over tilde not equal -1, is always totally geodesic. Additionally, if (kappa) over tilde not equal - 1 and (mu) over tilde not equal 0 the result can be partially reversed, which shows that the totally geodesic submanifold is invariant under the flow of characteristic vector field is tangent to the submanifold.