“…When trace(A) = 0, we obtain the non-unimodular semidirect products, among which we highlight the hyperbolic space H 3 and the Riemannian product H 2 × R. The geometry of minimal surfaces in homogeneous 3-manifolds of non-constant sectional curvature has been deeply studied in the last decade, specially in the case that the isometry group of the homogeneous manifold has dimension four. To indicate just a few relevant works in this area, we may cite [1,2,3,4,5,6,11,12,17,26,31,33,35]. An outline of the beginning of the theory of constant mean curvature surfaces in homogeneous 3-manifolds with a 4-dimensional isometry group can be consulted in [7,13].…”