title: Gravitational soliton
text: # Gravitational soliton
  
  A gravitational soliton is a soliton solution of the Einstein field equation. It can be separated into two kinds, a soliton of the vacuum Einstein field equation generated by the Belinski–Zakharov transform, and a soliton of the Einstein–Maxwell equations generated by the Belinski-Zakharov-Alekseev transform.
  
  