2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/145889The aim of this paper is to give examples of compact neutral 4-manifolds $(M,g)$ whose Ricci tensor $ρ$ satisfies the relation $\nabla_Xρ(X,X) =\frac13Xτg(X,X)$. We present also a family of new Einstein bi-Hermitian neutral metrics on ruled surfaces of genus $g>1$.12 pagesDifferential Geometry53C15text