Construction of Lax Connections by Exponentiation
  We propose a method for constructing the Lax connection of two-dimensional relativistic integrable sigma models on coset spaces by means of exponentiation of a suitable operator. We derive a simple quadratic relation that this operator must satisfy for an entire one-parameter family of connections to be flat. 
Niklas Beisert, Florian Luecker
math-ph hep-th math.MP