Semantics of Complex Sentences in Japanese

The important part of semantics of complex sentence is captured as relations among semantic roles in subordinate and main clause respectively. However if there can be relations between every pair of semantic roles, the amount of computation to identify the relations that hold in the given sentence is extremely large. In this paper, for semantics of Japanese complex sentence, we introduce new pragmatic roles called `observer' and `motivated' respectively to bridge semantic roles of subordinate and those of main clauses. By these new roles constraints on the relations among semantic/pragmatic roles are known to be almost local within subordinate or main clause. In other words, as for the semantics of the whole complex sentence, the only role we should deal with is a motivated.