Symmetries, Lagrangians and conserved vectors for forms of the   complex-valued Klein-Gordon Equation
  We analyse the complex-valued Klein-Gordon Equation from an integrability perspective by the implementation of the Lie Theory of Continuous Groups, where this equation is governed by power-law nonlinearity. We write the equations in terms of real dependent variables and examine both the two-dimensional and three-dimensional models. In the case of the two-dimensional model the analysis is extended by the determination of Noether point symmetries and conserved vectors via the construction of a Lagrangian. 
RM Morris, A Paliathanasis and PGL Leach
math-ph math.MP