A remark on nonlocal symmetries for the Calogero-Degasperis-Ibragimov-Shabat equation

Abstract

We consider the Calogero-Degasperis-Ibragimov-Shabat (CDIS) equation and find the complete set of its nonlocal symmetries depending on the local variables and on the integral of the only local conserved density of the equation in question. The Lie algebra of these symmetries turns out to be a central extension of that of local generalized symmetries.Comment: arxiv version is already officia