To solve the first challenge, we transform multilabel classification to multiple binary classification problems.
a given sentence s attached each pre-defined event type t forms an instance, which is expected to be labeled with 0 or 1 according to whether s contains an event of type t. For example, suppose there totally are 3 predefined types of events(denoted by t 1 , t 2 and t 3 ), and sentence s contains two events of type t 1 and t 3 , then it could be transformed to the following three instances: In this paradigm, sentences that convey multiple events will yield multiple positive pairs, thus the multi-label problem could be well solved.