6. The system of claim 5 , wherein creating the first and second leaned pseudo-documents comprises: determining a query vector according to the query pseudo-document; determining a first cluster vector according to the first pseudo-document; determining a second cluster vector according to the second pseudo-document; normalizing the query vector and the first cluster vector to the same length; normalizing the query vector and the second cluster vector to the same length; determining a first leaned cluster vector that points to a location that is between the query vector and the first cluster vector; and determining a second leaned cluster vector that points to a location that is between the query vector and the second cluster vector.
5. The system of claim 1 , wherein: the one or more processing units are further operable to: create a query pseudo-document from the determined plurality of term vectors; create a first leaned pseudo-document using the first pseudo-document and the query pseudo-document; and create a second leaned pseudo-document using the second pseudo-document and the query pseudo-document; wherein: identifying the first set of terms associated with the first cluster comprises using LSA of the first leaned pseudo-document; and identifying the second set of terms associated with the second cluster comprises using LSA of the second leaned pseudo-document.