Patent Document ID: 6128613
Application ID: 09069618

Base Claim:
1. In a computer, a method for establishing topic words to represent a document wherein the topic words are suitable for inclusion in a computer database index structure, the method comprising the steps of: accepting at least a portion of the document from a data input device, wherein the portion of the document includes words; determining a plurality of document keywords from the portion of the document; classifying each of the document keywords into one of a plurality of preestablished keyword classes; and selecting words as the topic words, each said selected word from a different one of the preestablished keyword classes, to minimize an entropy-based cost function on proposed topic words.

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Claim 2:
2. The method according to claim 1 wherein the cost function is a metric of dissimilarity between a first statistical distribution of likelihood of appearance by the plurality of document keywords in a typical document and a second statistical distribution of likelihood of appearance by the plurality of document keywords in a typical document, the second statistical distribution being approximated using proposed topic words.