where, F represents all the events in first sentence, independent variable b 1 (i) indicates the minimum number of causal relations that an event in F participates in, M represents the set of event mention pairs that can be mapped to the same sentence and l ij is a leakage variable that allows distant event mentions in F receiving a very high confidence value p ij to have a causal relation.
we encourage causal links between two event mentions that are in nearby sentences or can be mapped to the same sentence using coreference links 7 .