The meta book and size-dependent properties of written language

Evidence is presented for a systematic text-length dependence of the power-law index γ of a single book. The estimated γ values are consistent with a monotonic decrease from 2 to 1 with increasing text length. A direct connection to an extended Heap’s law is explored. The infinite book limit is, as a consequence, proposed to be given by γ = 1 instead of the value γ = 2 expected if Zipf’s law is universally applicable. In addition, we explore the idea that the systematic text-length dependence can be described by a meta book concept, which is an abstract representation reflecting the word-frequency structure of a text. According to this concept the word-frequency distribution of a text, with a certain length written by a single author, has the same characteristics as a text of the same length extracted from an imaginary complete infinite corpus written by the same author. 1 Author to whom any correspondence should be addressed. New Journal of Physics 11 (2009) 123015 1367-2630/09/123015+15$30.00 © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft