Method and system for information extraction

A system for extracting information from a natural language text corpus based on a natural language query, comprising:

• a text analysis unit for analyzing a natural language query with respect to phrases, phrase types, syntactic roles, word tokens of phrases, and lexical meaning of word tokens;
• storage means operatively connected to said text analysis unit, for storing the natural language text corpus;
• an indexer, operatively connected to said storage means, for indexing the natural language text corpus;
• an index, operatively connected to said indexer, for storing said indexed natural language text corpus;
• a query manager, operatively connected to said text analysis unit, comprising means for creating surface variants for at least one phrase of the natural language query, said surface variants each having the same phrase type as said at least one phrase of the natural language query, and each comprising a word token being a lexical head and having the same lexical meaning as a word token being a lexical head of said at least one phrase of the natural language query, and means for comparing said surface variants and said at least one phrase of the natural language query with the indexed natural language text corpus in said index;
• and
• a result manager operatively connected to said index, for extracting, from said indexed and stored natural language text corpus, each portion of text comprising a string of word tokens that matches any one of said surface variants or said analyzed natural language query.