Catalogue of Artificial Intelligence Techniques
Keywords: case roles, surface text
Categories: Natural Language
Author(s): Karen Sp\"arck Jones
A widely used device for the determination and representation of text meaning, based on the organisation of information primarily around verbs, or actions, by case roles, e.g., agent, instrument, location. Case frames are usually small-scale structures oriented towards linguistic units like sentences, as opposed to the typical large-scale structures oriented to world knowledge represented by Frames. Though reference to Fillmore's linguistically-motivated ideas is conventional, there is great variation in the treatment of every aspect of case frames, e.g., their relation to features of the surface text (is the subject of the sentence the agent?), their number (ten or thirty?), their status (obligatory or optional?), the constraints on their fillers (is the agent HUMAN?), etc. Conceptual Dependency, for example, uses a small number of deep cases referring primarily to underlying rather than surface relations. See also Case Grammar.
- Bruce, B., Case systems for natural language Artificial Intelligence 6 (1975), 327--360.