ANNALES POLONICI MATHEMATICI, cilt.112, sa.2, ss.115-125, 2014 (SCI-Expanded)
A Walker 4-manifold is a pseudo-Riemannian manifold (M-4, g) of neutral signature, which admits a field of parallel null 2-planes. We study almost paracomplex structures on 4-dimensional para-Kahler-Walker manifolds. In particular, we obtain conditions under which these almost paracomplex structures are integrable, and the corresponding para-Kahler forms are symplectic. We also show that Petean's example of a nonflat indefinite Kahler-Einstein 4-manifold is a special case of our constructions.