Nonabelian duality and analytic continuation of instantons
  Within the framework of the gauge O(1,3)\times O(1,3)-theory, an extension of the Belavin-Polyakov-Schwarz-Tyupkin ansatz is proposed by incorporation there the Levi-Civita tensor. The duality properties of the theory, admitting introduction the complex structure, are such that selfduality condition of the field tensor is an equation for complex-analytic function. New type of duality is found out. 
A. L. Koshkarov