The relation between the Toda hierarchy and the KdV hierarchy
  Under three relations connecting the field variables of Toda flows and that of KdV flows, we present three new sequences of combination of the equations in the Toda hierarchy which have the KdV hierarchy as a continuous limit. The relation between the Poisson structures of the KdV hierarchy and the Toda hierarchy in continuous limit is also studied. 
Yunbo Zeng, Runliang Lin and Xin Cao (Tsinghua University, Beijing,   P.R. China)