We study the formal and linguistic properties of a class of parenthesis-free categorial grammars derived from those of Ades and Steedman by varying the set of reduction rules. We characterize the reduction rules capable of generating context-sensitive languages as those having a partial combination rule and a combination rule in the reverse direction. We show that any categorial language is a permutation of some context-free language, thus inheriting properties dependent on symbol counting only. We compare some of their properties with other contemporary formalisms. .
