This project is concerned with mathematical techniques fromnatural language processing systems- specifically, fromunification-based grammar formalism- to help in the design odata and knowledge bases. These techniques include the use offeature theory, features logic, hyperset theory, and type systemsfrom polymorphic functional programming languages. The goal ofthe project is to use these techniques to move knowledge and datamodels closer together, while providing for at least some aspectsof heterogeneity in knowledge bases.