The AdS/CFT correspondence in the PP-wave limit

We consider the correspondence between IIB string theory on the maximally supersymmetric PP-wave and the BMN sector of N = 4 SYM theory. At the level of the interacting (string) theory, the matching between these two descriptions is not yet fully understood. Here we review the tests supporting the simple proposal that relates the 3-string interaction to the correlation functions among the BMN operators.