A Mathematical Structure Underlying Sentences and Its Connection with Short–Term Memory

The purpose of the present paper is to further investigate the mathematical structure of sentences—proposed in a recent paper—and its connections with human short–term memory. This structure is defined by two independent variables which apparently engage two short–term memory buffers in a series. The first buffer is modelled according to the number of words between two consecutive interpunctions—variable referred to as the word interval, IP—which follows Miller’s 7±2 law; the second buffer is modelled by the number of word intervals contained in a sentence, MF, ranging approximately for one to seven. These values result from studying a large number of literary texts belonging to ancient and modern alphabetical languages. After studying the numerical patterns (combinations of IP and MF) that determine the number of sentences that theoretically can be recorded in the two memory buffers—which increases with the use of IP and MF—we compare the theoretical results with those that are actually found in novels from Italian and English literature. We have found that most writers, in both languages, write for readers with small memory buffers and, consequently, are forced to reuse sentence patterns to convey multiple meanings.