Abstract: The present invention can be used in a natural language processing system to determine a relationship (such as similarity in meaning) between two textual segments. The relationship can be identified or determined based on logical graphs generated from the textual segments. A relationship between first and second logical graphs is determined. This is accomplished regardless of whether there is an exact match between the first and second logical graphs. In one embodiment, the first graph represents an input textual discourse unit. The second graph, in one embodiment, represents information in a lexical knowledge base (LKB). The input graph can be matched against the second graph, if they have similar meaning, even if the two differ lexically or structurally.

Abstract: A method of computerized searching receives parameters of a search query from a user and adds a restriction to the parameters to require that at least two of the search terms of the search query appear in a same sentence in a document. A representation of a set of documents is then searched based on the parameters of the search query and the added restriction. Documents that meet the search parameters and the added restriction are thus identified.