Categorial grammar analyzes linguistic syntax and semantics in terms of type theory and lambda calculus. A major attraction of this approach is its unifying power, as its basic function/argument structures occur across the foundations of mathematics, language and computation. This paper considers, in a light example-based manner, where this elegant logical paradigm stands when confronted with the wear and tear of reality. Starting from a brief history of the Lambek tradition since the 1980s, we discuss three main issues: (a) the fit of the lambda calculus engine to characteristic semantic structures in natural language, (b) the coexistence of the original type-theoretic and more recent modal interpretations of categorial logics, and (c) the place of categorial grammars in the complex total architecture of natural language, which involves - amongst others - mixtures of interpretation and inference.

Logics for expressing properties of Petri hypernets, a visual formalism for modelling mobile agents, are proposed. Two classes of properties are of interest—the temporal evolution of agents and their structural correlation. In particular, we investigate how the classes can be combined into a logic capable of expressing the dynamic evolution of the structural correlation. The problem of model checking properties of a class of the logic on Petri hypernets is shown to be PSPACE-complete.