Energy characteristics of subordination chains
  We consider subordination chains of simply connected domains with smooth boundaries in the complex plane. Such chains admit Hamiltonian and Lagrangian interpretations through the Loewner-Kufarev evolution equations. The action functional is constructed and its time variation is obtained. It represents the infinitesimal version of the action of the Virasoro-Bott group over the space of analytic univalent functions. 
Alexander Vasil'ev