The "ghost" symmetry in the CKP hierarchy
  In this paper, we systematically study the "ghost" symmetry in the CKP hierarchy through its actions on the Lax operator, dressing operator, eigenfunctions and the tau function. In this process, the spectral representation of the eigenfunction is developed and the squared eigenfunction potential is investigated. 
Jipeng Cheng, Jingsong He
nlin.SI math-ph math.MP