Dispersion relations and speeds of sound in special sectors for the   integrable chain with alternating spins
  Based on our previous analysis \cite{doerfel3} of the anisotropic integrable chain consisting of spins $s=1/2$ and $s=1$ we compare the dispersion relations for the sectors with infinite Fermi zones. Further we calculate the speeds of sound for regions close to sector borders, where the Fermi radii either vanish or diverge, and compare the results. 
B.-D. Doerfel and St. Meissner (HU Berlin)