Vanishing conharmonic tensor of normal locally conformal almost cosymplectic manifold

summary:The main purpose of the present paper is to study the geometric properties of the conharmonic curvature tensor of normal locally conformal almost cosymplectic manifolds (normal LCAC-manifold). In particular, three conhoronic invariants are distinguished with regard to the vanishing conharmonic tensor. Subsequentaly, three classes of normal LCAC-manifolds are established. Moreover, it is proved that the manifolds of these classes are $ \eta $-Einstein manifolds of type $ (\alpha,\beta) $. Furthermore, we have determined $ \alpha $ and $ \beta $ for each class