Let (M,g,J) be a Kaehler manifold and Ric is the Ricci curvature of g. Then I define:
α(X,Y)=g((JRic+RicJ)X,Y)
We have α∈Λ2(TM). Moreover we have dα=0, because ∇J=0 and we take ∇Ric=0. So, we obtain a closed form and a class of cohomology ˙α∈H2(M,R).
Is ˙α an invariant of the manifold M?