The Mathematics of Sentence Structure

The aim of this paper is to obtain an effective rule (or algorithm) for distinguishing sentences from nonsentences, which works not only for the formal languages of interest to the mathematical logician, but also for natural languages such as English, or at least for fragments of such languages. An attempt to formulate such an algorithm is implicit in the work of Ajdukiewicz (1935). His method, later elaborated by Bar-Hillel (1953), depends on a kind of arithmetization of the so-called parts of speech, here called syntactic types.