The log likelihood of a document is the sum of the log likelihoods of all pairs of mentions: (2) where m is the set of mentions in the document, and x is the set of variables representing each pairwise coreference decision x i,j .
for comparison, we also give the results of the COREf-ILP system of Denis and Baldridge (2007), which was also based on a naïve pairwise classifier.