Now, if a query is more probable given a language model based on document D 1 than given a language model based on document D 2 , we can then hypothesize that document D 1 is more likely to be relevant to the query than document D 2 .
for a more detailed discussion of the relationships between the classical (discriminative) probabilistic IR models and recent generative probabilistic IR models, we refer the reader to Kraaij and Spitters (2003).