EP can be thought of as a more flexible generalization of belief propagation, which has been used several times in NLP (Smith and Eisner, 2008;Niehues and Vogel, 2008;Cromières and Kurohashi, 2009;Burkett and Klein, 2012).
eP allows for the arbitrary choice of messages (thef m ), meaning that we can use structured messages like anchored PCFGs.