Determination of the chiral pion-pion scattering parameters: a proposal
  An explicitly crossing-symmetric decomposition of the pion-pion scattering amplitudes into low- and high-energy components is established. The high-energy components are entirely determined by absorptive parts at high energies. With the exception of the two leading-order parameters, all the parameters appearing in the one- and two-loop chiral amplitudes are determined by the high-energy components of the exact amplitudes. 
G. Wanders (University of Lausanne)