Asymptotically flat 4-manifolds (Q1924642)

Studying noncompact manifolds with a flatness property, there is the notion of an asymptotically Euclidean manifold, and there is the notion of an asymptotically flat manifold which is defined in terms of curvature decay. Asymptotically Euclidean manifolds are asymptotically flat, but the paper gives an asymptotically flat example in dimension 4 which is not asymptotically Euclidean. The constructed manifold is \(\mathbb{R}^4\) with a metric of Berger type.