The Euclidean-space conjecture for expanding algebraic solitons

An expanding algebraic soliton is a homogeneous Ricci soliton whose soliton structure is algebraic. Euclidean-space conjecture. Any expanding algebraic soliton is diffeomorphic to a Euclidean space. The source states that this formulation was proved equivalent to the conjecture for connected homogeneous Einstein manifolds of negative scalar curvature. Its resolution is not given in the supplied text.