According to this, documents that should be retrieved for a query of the form A or B, should be in the fuzzy set associated with the union of the two sets A and B. Similarly, the documents that should be retrieved for a query of the form A and B, should be in the fuzzy set associated with the intersection of the two sets. Hence, it is possible to define the similarity of a document to the or query to be max(dA, dB) and the similarity of the document to the and query to be min(dA, dB). The MMM model tries to soften the Boolean operators by considering the query-document similarity to be a linear combination of the min and max document weights