Spatial Reference And Semantic Nets

SUMMARY This paper presents an analysis in a semantic net formalism of the semantic structure of English sentences containing references to spatial-location. Spatial reference, hereafter-SR, provides either static location or motional information John is at home, Fred ran across the street to the store. .The task for the semantic analysis of sentences with SR's is to,make clear what is being positioned. THis has been difficult to do. Previous proposals have left unanalyzed many phenomena including important motional references. This paperv* main conclusion is that a much improved analysis can be obtained by representing the SR's as positioning abstract events and states of affairs. The analysis in semantic nets has the location of an event or state of affairs represented as a node which is linked to the node showing the event or state by arcs: indicating its staus as the spatial attribute. A few SR's are shown as naming these locational entities, which we call place ,object. These SR' s involve examples with "where", "here", and "there" However, most SRts are represented as relating place objects to the position of objects in the manner of prepositional phrases. This primacy ok prepositions is argued for in the paper. Motional references are allowed for by functions represented in the nets which produce parts of place objects which are then positioned by prepositional f c m s. The necessary ordering that'comes with motional references is allowed for by associating temporal elements with the functions. While the positioned elements are simple, the overall semantic structure of the sentences containing SR's is often complicated by the involvement of more than one event or state of affairs. The paper includes a survey of the sentential semantic structures necessary to deal with SR's. A similar complexity is necessary to deal with the informakion on the location of objects which is gained from sentences with SR's. The paper suggests-the use of inference rules to allow for this. The most surprising of the paper's oonclusions is that a strong tie exists between referehces to space and temporal information. In fact, the locations of all events and states of affairs placed by SR's are argued to be locations in both space and time. The effect of this conclusion is most clearly seen in a formalized definition of the primitives of the semantic seructures , which is also presented in semantic nets. There, as ane possible interpretation of the place object, …