  In his paper "The Mumford Dynamical System and Hyperelliptic Kleinian
Functions" (see arXiv:2402.09218), Victor Buchstaber developed the
differential-algebraic theory of the Mumford dynamical system. The key object
of this theory is the (P,Q)-recursion introduced in his paper. In the present
paper, we further develop the theory of (P,Q)-recursion and describe its
connections to the Korteweg-de Vries hierarchy, the Lenard operator, and the
Gelfand-Dikii recursion.
