Certain Class of Almost Cosymplectic Manifolds with Kahlerian Leaves

We consider a class of almost cosymplectic manifolds with Kahlerian leaves and ?-parallel tensor h' = f ? h. We prove that there exists a distribution of eigenvalues of h' with totally umbilical leaves and foliations whose leaves are minimal almost Kahlerian manifolds immersed as hypersurfaces of almost cosymplectic manifolds. We show that if the spectrum of h' is {0, ?, -?}, with 0 as simple eigenvalue and ? a positive real number and ?(?)h' = 0, the manifolds under consideration are (-?(2))-space. Supporting examples are also established.