Main concepts of quasi-stationary distributions (QSDs) for killed processes are the focus of the present volume. For diffusions, the killing is at the boundary and for dynamical systems there is a trap. The authors present the QSDs as the ones that allow describing the long-term behavior conditioned to not being killed. Studies in this research area started with Kolmogorov and Yaglom and in the last few decades have received a great deal of attention. The authors provide the exponential distribution property of the killing time for QSDs, present the more general result on their existence and study the process of trajectories that survive forever. For birth-and-death chains and diffusions, the existence of a single or a continuum of QSDs is described. They study the convergence to the extremal QSD and give the classification of the survival process. In this monograph, the authors discuss Gibbs QSDs for symbolic systems and absolutely continuous QSDs for repellers. The findings described are relevant to researchers in the fields of Markov chains, diffusions, potential theory, dynamical systems, and in areas where extinction is a central concept. The theory is illustrated with numerous examples. The volume uniquely presents the distribution behavior of individuals who survive in a decaying population for a very long time. It also provides the background for applications in mathematical ecology, statistical physics, computer sciences, and economics.

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In July 1996, a conference was organized by the editors of this volume at the Mathematische Forschungsinstitut Oberwolfach to honour Egbert Brieskorn on the occasion of his 60th birthday. Most of the mathematicians invited to the conference have been influenced in one way or another by Brieskorn's work in singularity theory. It was the first time that so many people from the Russian school could be present at a conference in singularity theory outside Russia. This volume contains papers on singularity theory and its applications, written by participants of the conference. In many cases, they are extended versions of the talks presented there. The diversity of subjects of the contributions reflects singularity theory's relevance to topology, analysis and geometry, combining ideas and techniques from all of these fields, as well as demonstrating the breadth of Brieskorn's own interests. This volume contains papers on singularity theory and its applications, written by participants of the conference. In many cases, they are extended versions of the talks presented there. The diversity of subjects of the contributions reflects singularity theory's relevance to topology, analysis and geometry, combining ideas and techniques from all of these fields, as well as demonstrates the breadth of Brieskorn's own interests.

'Buz Brock's contribution to economic theory in general and economic dynamics in particular are characterized by an unmatched richness of ideas and by deep theoretical, empirical as well as computational analysis. Brock's contribution to economic dynamics range from one extreme of the field, global stability of stochastic optimal growth models, to another extreme, market instability and nonlinearity in economic and financial modelling and data analysis. But his work also includes environmental and economic policy issues and, more recently, the modelling of markets as complex adaptive systems. This collection of essays reflects Brock's richness of ideas that have motivated economists for more than three decades already and will continue to influence many economists for the next decades to come.' - Cars H. Hommes, University of Amsterdam, The Netherlands 'Buz Brock has been, from the beginning of his career, one of the most original thinkers in dynamic economics. His early work showed that growth with random elements could be studied effectively and above all posed exactly the right questions. His more recent work has brought complexity theory to the fore and shown its implications for financial and other markets. In the process, he has both introduced and used econometric tools to show the relevance of his work to empirically observed phenomena. It is very useful to have his work in collected form.' - Kenneth J. Arrow, Stanford University, US This outstanding collection of William Brock's essays illustrates the power of dynamic modelling to shed light on the forces for stability and instability in economic systems. The articles selected reflect his best work and are indicative both of the type of policy problem that he finds challenging and the complex methodology that he uses to solve them. Also included is an introduction by Brock to his own work, which helps tie together the main aspects of his research to date.