Method for learning local syntactic relationships for use in example-based information-extraction-pattern learning

In a computerized example-based pattern learning element of an information-extraction system, said element having as input, texts containing user-identified events and as output, information-extraction patterns that can be used to extract similar events from similar texts, a method for learning local syntactic relationships to be used as components within information-extraction patterns learned by said pattern learning element, said method comprising the steps of:

• analyzing an example text and event given to the learning element to establish that the learning element contains an incomplete current dictionary of local syntactic relationships needed to form paths of relationships between all constituents of the text that participate in the event, thus making the learning element unable to form a new extraction pattern from said example text and event;
• thereupon finding the closest pair of constituents within the example text that cannot be related by local syntactic relationships in the current dictionary;
• inferring a new local syntactic relationship between said closest pair, said new local syntactic relationship being expressed as a finite state machine;
• adding said finite state machine to said dictionary so that said finite state machine can be embedded in patterns produced by said learning element;
• and
• re-invoking the learning element on said example text and said example event to learn an information extraction pattern from said example text and said example event by making use of the newly-inferred local syntactic relationship finite state machine.