Almost Kenmotsu f-manifolds

A class of manifolds which admit an f-structure with s-dimensional parallelizable kernel is introduced and studied. Such manifolds are called almost Kenmotsu f.pk-manifolds. If s = 1, one obtains almost Kenmotsu manifolds and, if s = 2, they carry a locally conformal almost Kahler structure. Several foliations canonically associated with an almost Kenmotsu f.pk-manifold are studied. Locally conformal almost Kenmotsu f.pk-manifolds are characterized. If s >= 2, they set up a class which is disjoint from that of locally conformal almost C-manifolds.