Harmonic almost contact metric manifolds revisited
The study of harmonicity for almost contact metric structures was initiated by Vergara-Diaz and Wood and continued by Gonzalez-Davila and the present author. By using the intrinsic torsion and some restriction on the type of almost contact metric structure, Gonzalez-Davila and the present author have characterised harmonic structures by showing conditions relating harmonicity and classes of almost contact metric structures. Here we do this in a more general context. Moreover, the harmonicity of almost contact metric structures as a map is also done in such a general context. Finally, some remarks on the classification of almost contact metric structures are exposed.