M. Emery – författare

Exploration of the nature of human communication and the media is a pre­ requisite to any assessment of the likely future role of communications . . We cannot assume that the nature of these things is transparently obvious to everyone and therefore commonly understood. Three developments in recent decades should adequately warn against such an assumption. First, we had the fiasco of social scientists trying to apply Shannon's mathematical theory of information as if it were a theory of human communication. 'In Shannon's use of information we cannot speak of how much information a person has only how much a message has. ' (Ackoff and Emery, 1972, p. 145). They would not have wandered into that blind alley if they had stopped to think about the nature of human communication. Second was the belated but wholehearted acceptance of the Heider theory of balance and its subse­ quent wane. Its wane had nothing to do with its inherent merits. It waned because it could not survive on the Procrustean bed of the psychologists' theory of choice. It did not occur to the psychologists to question their as­ sumptions about how people made the choices that lead to purposeful com­ munication (Ackoff and Emery, 1972, p. 58). The last example has been the bitter and unended furore about McLuhan. This time the psychologists and sociologists haye been strangely quiet but we can be sure this does not imply acquiescence in McLuhan's views.

Researchers and graduate students in the theory of stochastic processes will find in this 35th volume some thirty articles on martingale theory, martingales and finance, analytical inequalities and semigroups, stochastic differential equations, functionals of Brownian motion and of Levy processes. Ledoux's article contains a self-contained introduction to the use of semigroups in spectral gaps and logarithmic Sobolev inequalities; the contribution by Emery and Schachermayer includes an exposition for probabilists of Vershik's theory of backward discrete filtrations.

Besides topics traditionally found in the Seminaire de Probabilites (Martingale Theory, Stochastic Processes, questions of general interest in Probability Theory), this volume XXXIII presents nine contributions to the study of filtrations up to isomorphism. It also contains three graduate courses: Dynamics of stochastic algorithms, by M. Benaim; Simulated annealing algorithms and Markov chains with rare transitions, by O. Catoni; and Concentration of measure and logarithmic Sobolev inequalities, by M. Ledoux. These up to date courses present the state of the art in three matters of interest to students in theoretical or applied Probability Theory, and to researchers as well.

This volume contains 19 contributions to various subjects in the theory of (commutative and non-commutative) stochastic processes. It also provides a 145-page graduate course on branching and interacting particle systems, with applications to non-linear filtering, by P. del Moral and L. Miclo.

This volume contains lectures given at the Saint-Flour Summer School of Probability Theory during 17th Aug. - 3rd Sept. 1998. The contents of the three courses are the following:- Continuous martingales on differential manifolds. - Topics in non-parametric statistics. - Free probability theory. The reader is expected to have a graduate level in probability theory and statistics. This book is of interest to PhD students in probability and statistics or operators theory as well as for researchers in all these fields. The series of lecture notes from the Saint-Flour Probability Summer School can be considered as an encyclopedia of probability theory and related fields.