1. A computer-implemented method comprising: learning sets of equivalent syntactic patterns from a corpus of documents; receiving a set of one or more input documents; processing the set of one or more input documents for one or more expressions matching a set of equivalent syntactic patterns from among the sets of equivalent syntactic patterns; selecting a syntactic pattern from among the set of equivalent syntactic patterns for a headline, the syntactic pattern reflecting a main event described by the set of one or more input documents; and generating the headline using the syntactic pattern.