Quasi-classical generalized CRF structures

Abstract

In an earlier paper, we studied manifolds M endowed with a generalized F structure $\Phi \in \mathrm{End}(TM\oplus T^*M)$, skew-symmetric with respect to the pairing metric, such that $\Phi ^3+\Phi =0$. Furthermore, if $\Phi$ is integrable (in some well-defined sense), $\Phi$ is a generalized CRF structure. In the present paper, we study quasi-classical generalized F and CRF structures, which may be seen as a generalization of the holomorphic Poisson structures (it is well known that the latter may also be defined via generalized geometry). The structures that we study are equivalent to a pair of tensor fields $(A\in \mathrm{End}(TM),\pi \in \wedge ^2TM)$, where $A^3+A=0$ and some relations between A and $\pi$ hold. We establish the integrability conditions in terms of $(A,\pi )$. They include the facts that A is a classical CRF structure, $\pi$ is a Poisson bivector field and $\mathrm{im}\,A$ is a (non)holonomic Poisson submanifold of $(M,\pi )$. We discuss the case where either $\mathrm{ker}\,A$ or $\mathrm{im}\,A$ is tangent to a foliation and, in particular, the case of almost contact manifolds. Finally, we show that the dual bundle of $\mathrm{im}\,A$ inherits a Lie algebroid structure and we briefly discuss the Poisson cohomology of $\pi$, including an associated spectral sequence and a Dolbeault type grading.