Master symmetry in the $AdS_5\times S^5$ pure spinor string
  We lift the set of classical non-local symmetries recently studied by Klose, Loebbert, and M\"unkler in the context of $\mathbb Z_2$ cosets to the pure spinor description of the superstring in the $AdS_5\times S^5$ background. 
Osvaldo Chandia, William Divine Linch III and Brenno Carlini Vallilo
hep-th