In our previous work ( Zhang and Chai , 2009 ) , conversation entailment is formulated as the following : given a conversation segment D which is represented by a set of clauses D = d1 â§ ... â§ dm , and a hypothesis H represented by another set of clauses H = h1 â§ ... â§ hn , the prediction on whether D entails H is determined by the product of probabilities that each hypothesis clause hj is entailed from all the conversation segment clauses d1 ... dm as follows .