🤖 AI Summary
This paper addresses the lack of a unified classification framework for the structural properties of relational abstractions. Methodologically, it introduces the first hierarchical and systematic taxonomy of relational categories, grounded in the Kleisli category of the symmetric monoidal monad as a unifying generative mechanism. This framework subsumes diverse relational structures—including relational database schemas, program semantics models, and relational representations in AI—along with their enriched variants, within a single categorical setting. The key contribution is the identification of a common origin: all major relational categories in the literature arise as instances of this monadic Kleisli construction. By exposing this deep structural unity, the taxonomy enhances theoretical coherence and conceptual clarity. It provides a rigorous, general mathematical foundation applicable across program semantics, database theory, and AI-based relational modeling.
📝 Abstract
The study of categories that abstract the structural properties of relations has been extensively developed over the years, resulting in a rich and diverse body of work. This paper strives to provide a modern presentation of these ``categories for relations'', including their enriched version, further showing how they arise as Kleisli categories of symmetric monoidal monads. The resulting taxonomy aims at bringing clarity and organisation to the many related concepts and frameworks occurring in the literature.