This text serves as an introduction to the use of nonlinear symmetries in studying, simplifying and solving nonlinear equations. Part One provides a self-contained introduction to the theory. This emphasizes an intuitive understanding of jet spaces and the geometry of differential equations, and a special treatment of evolution problems and dynamical systems, including original results. In Part Two the theory is applied to equivariant dynamics, to bifurcation theory and to gauge symmetries, reporting recent results by the author. In particular, the fundamental results of equivariant...

Gathering together a number of experts in the world, the 27th Jerusalem Symposium was devoted to the theme of the modelling of biomolecular structures and mechanisms. As a result of recent growth in both importance and audience, the papers contained in this volume present an evaluation of the status of the present knowledge in this field. The main topics covered by this year's Symposium include nucleic acids and their interactions, proteins and their interaction, membranes and their interactions, enzymatic processes and the pharmacological and medical aspects of these subjects. Readers should...

This text is dedicated to the contributions of women ichthyologists. Three colleagues were selected to represent all women ichthyologists, Ethelwynn Trewavas (ET), Rosemary Lowe-McConnell (Ro) and Eugenie Clark (Genie). All have had distinguished professional careers and have contributed in their own ways to their science. The career of each is highlighted by a personal interview with one of the editors of the volume, a bibliography of their lifetime publications, and a biography of their careers.

Probability Theory, Theory of Random Processes and Mathematical Statistics are important areas of modern mathematics and its applications. They develop rigorous models for a proper treatment for various 'random' phenomena which we encounter in the real world. They provide us with numerous tools for an analysis, prediction and, ultimately, control of random phenomena. Statistics itself helps with choice of a proper mathematical model (e.g., by estimation of unknown parameters) on the basis of statistical data collected by observations. This volume is intended to be a concise textbook for a...

Research in the theory of trigonometric series has been carried out for over two centuries. The results obtained have greatly influenced various fields of mathematics, mechanics, and physics. Nowadays, the theory of simple trigonometric series has been developed fully enough (we will only mention the monographs by Zygmund 15, 16] and Bari 2]). The achievements in the theory of multiple trigonometric series look rather modest as compared to those in the one-dimensional case though multiple trigonometric series seem to be a natural, interesting and promising object of investigation. We should...

Although some examples of phase portraits of quadratic systems can already be found in the work of Poincare, the first paper dealing exclusively with these systems was published by Buchel in 1904. By the end of the 20th century an increasing flow of publications resulted in nearly a thousand papers on the subject.

This book attempts to give a presentation of the advance of our knowledge of phase portraits of quadratic systems, paying special attention to the historical development of the subject. The book organizes the portraits into classes, using the notions of finite and infinite...

I don't know who Gigerenzer is, but he wrote something very clever that I saw quoted in a popular glossy magazine: "Evolution has tuned the way we think to frequencies of co-occurances, as with the hunter who remembers the area where he has had the most success killing game." This sanguine thought explains my obsession with the division algebras. Every effort I have ever made to connect them to physics - to the design of reality - has succeeded, with my expectations often surpassed. Doubtless this strong statement is colored by a selective memory, but the kind of game I sought, and still...

This book covers the basic elements of difference equations and the tools of difference and sum calculus necessary for studying and solv- ing, primarily, ordinary linear difference equations. Examples from various fields are presented clearly in the first chapter, then discussed along with their detailed solutions in Chapters 2-7. The book is in- tended mainly as a text for the beginning undergraduate course in difference equations, where the "operational sum calculus" of the di- rect use of the discrete Fourier transforms for solving boundary value problems associated with difference...

This book examines an abstract mathematical theory, placing special emphasis on results applicable to formal logic. If a theory is especially abstract, it may find a natural home within several of the more familiar branches of mathematics. This is the case with the theory of closure spaces. It might be considered part of topology, lattice theory, universal algebra or, no doubt, one of several other branches of mathematics as well. In our development we have treated it, conceptually and methodologically, as part of topology, partly because we first thought ofthe basic structure involved...

From a modelling point of view, it is more realistic to model a phenomenon by a dynamic system which incorporates both continuous and discrete times, namely, time as an arbitrary closed set of reals called time-scale or measure chain. It is therefore natural to ask whether it is possible to provide a framework which permits us to handle both dynamic systems simultaneously so that one can get some insight and a better understanding of the subtle differences of these two different systems. The answer is affirmative, and recently developed theory of dynamic systems on time scales offers the...