Nine-Parameter Electrovac Metric Involving Rational Functions

An analytically extended nine-parameter family of the electrovac rational function solutions of the Einstein-Maxwell equations generalizing the Chen-Guo-Ernst class of hyperextreme spacetimes is presented. The general four-soliton asymptotically flat solution possessing the equatorial symmetry and involving five independent real parameters is derived in a concise analytical form and its relevance to the equilibrium problem of two extreme particles is discussed.