Entropic nonextensivity: a possible measure of complexity

An updated review (corresponding to the inaugural talk delivered at the The International Workshop on Classical and Quantum Complexity and Nonextensive Thermodynamics, Denton, TX, April 3-6, 2000) of nonextensive statistical mechanics and thermodynamics is colloquially presented. Quite naturally the possibility emerges for using the value of q - I (entropic nonextensivity) as a simple and efficient manner to provide, at least for some classes of systems, some characterization of the degree of what is currently referred to as complexity (M. Gell-Mann, The Quark and the Jaguar, Freeman, New York, 1994). A few historical digressions are included as well. (C) 2001 Elsevier Science Ltd. All rights reserved.