ETA-RICCI SOLITONS ON HOPF HYPERSURFACES IN COMPLEX SPACE FORMS

The Eisenhart problem of finding parallel symmetric covariant tensor fields is solved in the framework of Hopf hypersurfaces. The results are interpreted in terms of -Ricci solitons, a natural generalization of Ricci solitons for the almost contact geometry. AMS 2010 Subject Classification: 53C40, 53C44, 53C25.