Generalized Eta-Einstein and $(\kappa ,\mu )$-structures

Abstract

Generalized $(\kappa ,\mu )$ structures occur in dimension 3 only. In this dimension 3, only K-contact structures can occur as generalized Eta-Einstein. On closed manifolds, Eta-Einstein, K-contact structures which are not D-homothetic to Einstein structures are almost regular. We also construct examples of compact, generalized Jacobi $(\kappa ,\mu )$-structures.