Feature structures allow for the representation of partial information.
Unification and generalization can then be defined as natural operations for merging partial information in the process of grammatical composition. In this framework, well-formedness amounts to derivability in the grammatical resource logic. Derivability is determined by the resource-logical formulas one assigns to the lexical atoms of the language. Recently, a number of proposals have been put forward for a genuine integration of these two frameworks. The course In categorial research, significant progress has been made in the understanding of the fine-structure of grammatical composition, and how this 'computational system' is driven by lexical type assignment.