Riemann--Hilbert problem for Camassa--Holm equation with step-like   initial data
  The Cauchy problem for the Camassa -- Holm equation with step-like initial conditions is reformulated as a Riemann -- Hilbert problem. The the initial value problem solution is obtained then in a parametric form from the Riemann -- Hilbert problem solution. 
Alexander Minakov
math-ph math.MP