Patent ID: 7676463

Claim:
A computer-implemented information exploration method that comprises: processing a set of documents with a computer to identify a hierarchy of clusters of documents, wherein the processing comprises: calculating a pseudo-document vector for each document in the set of documents; and computing the hierarchy of clusters from the pseudo-document vectors; and selecting with a computer one or more phrases from the set of documents as representative phrases for each cluster from a root cluster to leaf clusters in the hierarchy of clusters, wherein the selecting comprises: constructing a phrase-to-leaf node index for the hierarchy of clusters, wherein the phrase-to-leaf node index includes a list of phrases that occur in at least a predetermined number of documents of at least one of the leaf clusters, and for each phrase in the list of phrases, the phrase-to-leaf node index identifies each of the leaf clusters containing the phrase; and wherein constructing the phrase-to-leaf node index further comprises: constructing a suffix tree for each leaf cluster in the hierarchy of clusters; constructing a phrase index for each leaf cluster that includes a list of phrases shared by at least the predetermined number of documents in the leaf cluster; and combining the phrase indices of the leaf clusters in the hierarchy of cluster to construct the phrase-to-leaf node index.