INFORMATION RETRIEVAL AND ENCODING VIA SUBSTRING-NUMBER MAPPING

A finite-state network that supports substring-number mapping is compiled from a grammar that includes a plurality of classes of substrings. Each of the plurality of classes of substrings has a finite number of substrings. In applying the network to an input string, substrings are identified in the input string. Some or all of the substrings identified in the input string are mapped to a unique index within their class. This unique index is labeled with an identifier that identifies its class to define a labeled index. The string is encoded by forming a set of labeled indices using the labeled index of each substring of the input string.