Skyrme model on S_3 and Harmonic maps
  A non-linear sigma model mimicking the Skyrme model on S_3 is proposed and a family of classical solutions to the equations are constructed numerically. The solutions terminate into catastrophe-like spikes at critical values of the Skyrme coupling constant and, when this constant is zero, they coincide with the series of Harmonic maps on S_3 constructed some years ago by P. Bizon. 
Yves Brihaye, Claude Gabriel