springer jul 1989 (182 resultados)

Taschenbuch. Condición: Neu. Neuware - Computational synthetic geometry deals with methods for realizing abstract geometric objects in concrete vector spaces. This research monograph considers a large class of problems from convexity and discrete geometry including constructing convex polytopes from simplicial complexes, vector geometries from incidence structures and hyperplane arrangements from oriented matroids. It turns out that algorithms for these constructions exist if and only if arbitrary polynomial equations are decidable with respect to the underlying field. Besides such complexity theorems a variety of symbolic algorithms are discussed, and the methods are applied to obtain new mathematical results on convex polytopes, projective configurations and the combinatorics of Grassmann varieties. Finally algebraic varieties characterizing matroids and oriented matroids are introduced providing a new basis for applying computer algebra methods in this field. The necessary background knowledge is reviewed briefly. The text is accessible to students with graduate level background in mathematics, and will serve professional geometers and computer scientists as an introduction and motivation for further research.

Buch. Condición: Neu. Neuware - This book proposes a new methodology for the selection of one (model) from among a set of alternative econometric models. Let us recall that a model is an abstract representation of reality which brings out what is relevant to a particular economic issue. An econometric model is also an analytical characterization of the joint probability distribution of some random variables of interest, which yields some information on how the actual economy works. This information will be useful only if it is accurate and precise; that is, the information must be far from ambiguous and close to what we observe in the real world Thus, model selection should be performed on the basis of statistics which summarize the degree of accuracy and precision of each model. A model is accurate if it predicts right; it is precise if it produces tight confidence intervals. A first general approach to model selection includes those procedures based on both characteristics, precision and accuracy. A particularly interesting example of this approach is that of Hildebrand, Laing and Rosenthal (1980). See also Hendry and Richard (1982). A second general approach includes those procedures that use only one of the two dimensions to discriminate among models. In general, most of the tests we are going to examine correspond to this category.

Taschenbuch. Condición: Neu. Neuware - The enthusiastic response to the Dictionary has prompted this second substantially enlarged, revised and updated edition. It now contains essential details of the lives of over 2000 women from all periods, cultures and walks of life - from queens to cooks, engineers to entertainers, pilots to poisoners. The new entries include women who have hit the headlines in the past five years - from Cory Aquino to Madonna - but the historical coverage has also been broadened in response to new research and a special new feature is the extended treatment of women from Third World countries. With subsections for further reading, comprehensive subject index and bibliographical survey, the Macmillan Dictionary of Women's Biography is an invaluable reference source - and a fascinating bed-time read.

Buch. Condición: Neu. Neuware - Twenty years of numerical syntaxonomy.- An outline for data analysis in phyto sociology: past and present.- Influences of the individualistic concept of vegetation on syntaxonomy.- Similarity measures for structured data: a general framework and some applications to vegetation data.- New combinatorial clustering methods.- On the use of grammars in vegetation analysis.- A new numerical solution to traditional phytosociological tabular classification.- Syntaxonomy of the Onopordum acanthium communities in temperate and continental Europe.- A coenocline of the high-ranked syntaxa of ruderal vegetation.- Ecological species groups in forest communities in South Belgium.- On the delimitation of the Mesobromion and Xerobromion in Belgium and French Lorraine.- Classification of South Swedish Isoetid vegetation with the help of numerical methods.- Syntaxonomy of the Australian mangai refined through iterative ordinations.- Numerical revision of the Fagion illyricum alliance.- Numerical syntaxonomy of the tall-forb and tall-grass communities in the Tatra Mountains.- Partitioning and elevation gradient of vegetation from southeastern Ethiopia by probabilistic methods.- Numerical phytosociology of the subalpine belt of the Kazbegi region, Caucasus, USSR.- Phytogeographical analysis of a treeline community in Northern Yukon (NW-Canada).

Buch. Condición: Neu. Neuware - This book grew out of the conviction that the preparation and management of large-scale technological projects can be substantially improved. We have witnessed the often unhappy course of societal and political decision making concerning projects such as hazardous chemical installations, novel types of electric power plant or storage sites for solid wastes. This has led us to believe that probabilistic risk analysis, technical reliability analysis and environm,ental impact analysis are necessary but insufficient for making acceptable, and justifiable, social decisions about such projects. There is more to socio-technical decision making than applying acceptance rules based on neglige ably low accident probabilities or on maximum credible accidents. Consideration must also be given to psychological, social and political issues and methods of decision making. Our conviction initially gave rise to an international experts' workshop titled 'Social decision methodology for technological projects' (SDMTP) and held in May 1986 at the University of Groningen, the Netherlands, at a time when Cvetkovich spent a sabbatical there. The work shop - aimed at surveying the issues and listing the methods to address them - was the first part of an effort whose second part was directed at the production of this volume. Plans called for the book to deal systematically with the main problems of socio-technical decision making; it was to list a number of useful approaches and methods; and it was to present a number of integrative conclusions and recommendations for both policy makers and methodologists.

Buch. Condición: Neu. Neuware - If nothing else, the twelve papers assembled in this volume should lay to rest the idea that the interesting debates about the nature of science are still being conducted by 'internalists' vs. 'externalists,'' rationalists' vs. 'arationalists, n or even 'normative epistemologists' vs. 'empirical sociologists of knowledge. ' Although these distinctions continue to haunt much of the theoretical discussion in philosophy and sociology of science, our authors have managed to elude their strictures by finally getting beyond the post-positivist preoccupation of defending a certain division of labor among the science studies disciplines. But this is hardly to claim that our historians, philosophers, sociologists, and psychologists have brought about an 'end of ideology,' or even an 'era of good feelings,' to their debates. Rather, they have drawn new lines of battle which center more squarely than ever on practical matters of evaluating and selecting methods for studying science. To get a vivid sense of the new terrain that was staked out at the Yearbook conference, let us start by meditating on a picture. The front cover of a recent collection of sociological studies edited by one of us (Woolgar 1988) bears a stylized picture of a series of lined up open books presented in a typical perspective fashion. The global shape comes close to a trapezium, and is composed of smaller trapeziums gradually decreasing in size and piled upon each other so as to suggest a line receding in depth. The perspective is stylized too.

Buch. Condición: Neu. Neuware - Where do you begin to look for a recent, authoritative article on the diagnosis or management of a particular malignancy The few general oncology text books are generally out of the date. Single papers in specialized journals are informative but seldom comprehensive; these are often preliminary reports on a very limited number of patients. Certain general journals frequently publish good in depth reviews of cancer topics, and published symposium lectures are often the best overviewes available. Unfortunately, these reviews and supplements appear sporadically, and the reader can never be sure when a topic of special interest will be covered. Cancer Treatment and Research is a series of authoritative volumes which aim to meet this need. it is an attempt to establish a critical mass of oncology literature covering virtually all oncology topics, revised frequently to keep the coverage up to date, easily available on a single library shelf or by a single personal subscription. We have approached the problem in the following fashion. First, by dividing the oncology literature into specific subdivisions such as lung cancer, genito urinary cancer, pediatric oncology, etc. Second, by asking eminent authori ties in each of these areas to edit a volume on the specific topic on an annual or biannual basis. Each optic and tumor type is covered in a volume appear ing frequently and predictably, discussing current diagnosis, staging, markers, all forms of treatment modalities, basic biology, and more.

Buch. Condición: Neu. Neuware - When leaving the Victoria airport the day before our Colloquium, I saw a van of the Dunsmuir Lodge marked with big letters which I read as 'Alcohol Colloquium'. I do often make such blunders because of the global, casual, and careless way in which I read various ads, and checked myself quickly to read it correctly as 'Algol Colloquium'. Millions of fellow citizens could easily make the same mistake, and no apology could be expected. Even I read and hear the word alcohol more frequently than Algol, although I must say that Algols have given me more pleasure and fewer headaches over the years; in that, however, I may be a singularity, and possibly a pitiful one at that. Being appointed Chairman of the Scientific Organizing Committee, I may be deemed to be a purer' Algolist' than other investigators, although my range of active interests is much broader; and the same is true about all the 28 invited speakers and all the other participants of the Colloquium. Our interest are strongly diversified, but there are several good reasons that brought us together at this Colloquium.

Buch. Condición: Neu. Neuware - The last volume dealing with lung cancer in this series in Cancer Treatment and Research was published in 1986 and entitled Lung Cancer: Basic and Clinical Aspects. The present book continues the outline of the previous volume by presenting up-to-date information on lung cancer in critical reviews of new important basic and clinical concepts of lung cancer. The present volume has broadened the scope by also including chapters dealing with issues such as epidemiology, prophylaxis, and histopathology of lung cancer. The content of the book thus reflects the increasing awareness of a global disease that is more and more in focus, not only scientifically but also politically. The latter fact results increasingly in changes in health legisla tion, with prevention measures influencing everyday life. The great interest in the disease is natural, considering that more than one patient dies from lung cancer every minute globally. The first chapter is from the Cancer Unit, WHO, Geneva, and describes in detail the epidemiologic features of lung cancer, which is the second most frequent cancer in the world with 660,500 new cases annually; it will soon surpass stomach cancer as the leader. Thirty-one percent of the cases occur in developing countries, where the increase is especially dramatic.

Buch. Condición: Neu. Neuware - This edition is the labor of many enthousiastic scientists who were invited to teach at a NATO Advanced Study Institute on the 'Spectroscopy of Inorganic Bioactivators' which took place on August 20 -30, 1988 at Club Poseidon, Loutraki, Greece. In this book the subjects were taught through several well prepared lectures. These lectures stretch the fact that scientific knowledge is the painfully gathered product of many wonderful human minds. I made an attempt to divide the lectures into separate chapters, however, there is interaction among the lectures, as I hope the book will show. First, there is introductory on an lecture supercomputing and super computers and their applications to solving structures of biological molecules followed by a state-of-the-art x-ray diffraction method at pi co second times. Important new advances have been made in x-ray diffraction analysis at picosecond times, in Hadamard spectroscopy, in micro-Raman spectroscopy in the Near Infrared region (1. 01 ~m) and remote sensing by Fourier Transform Infrared Spectroscopy. The chapters that follow include applications of spectroscopic technique to vii viii biologically important molecules, such as, DNA, proteins, membranes, and metal ion-biological molecule interactions. I would like to express my thanks to all the authors for their contributions and their cooperation in submitting their manuscript. I also thank the NATO Science Committee for making this possible. The field looks very promising for significant and exciting developments in the application of spectroscopy to bioactivators.

Buch. Condición: Neu. Neuware - Various brain areas of mammals can phyletically be traced back to homologous structures in amphibians. The amphibian brain may thus be regarded as a kind of 'microcosm' of the highly complex primate brain, as far as certain homologous structures, sensory functions, and assigned ballistic (pre-planned and pre-pro grammed) motor and behavioral processes are concerned. A variety of fundamental operations that underlie perception, cognition, sensorimotor transformation and its modulation appear to proceed in primate's brain in a way understandable in terms of basic principles which can be investigated more easily by experiments in amphibians. We have learned that progress in the quantitative description and evaluation of these principles can be obtained with guidance from theory. Modeling - supported by simulation - is a process of transforming abstract theory derived from data into testable structures. Where empirical data are lacking or are difficult to obtain because of structural constraints, the modeler makes assumptions and approximations that, by themselves, are a source of hypotheses. If a neural model is then tied to empirical data, it can be used to predict results and hence again to become subject to experimental tests whose resulting data in tum will lead to further improvements of the model. By means of our present models of visuomotor coordination and its modulation by state-dependent inputs, we are just beginning to simulate and analyze how external information is represented within different brain structures and how these structures use these operations to control adaptive behavior.

Taschenbuch. Condición: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -These notes give the basic ingredients of the theory of weighted Hardy spaces of tempered distribution on Rn and illustrate the techniques used. The authors consider properties of weights in a general setting; they derive mean value inequalities for wavelet transforms and introduce halfspace techniques with, for example, nontangential maximal functions and g-functions. This leads to several equivalent definitions of the weighted Hardy space HPW. Fourier multipliers and singular integral operators are applied to the weighted Hardy spaces and complex interpolation is considered. One tool often used here is the atomic decomposition. The methods developed by the authors using the atomic decomposition in the strictly convex case p 1 are of special interest. 204 pp. Englisch.

Taschenbuch. Condición: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -Computational synthetic geometry deals with methods for realizing abstract geometric objects in concrete vector spaces. This research monograph considers a large class of problems from convexity and discrete geometry including constructing convex polytopes from simplicial complexes, vector geometries from incidence structures and hyperplane arrangements from oriented matroids. It turns out that algorithms for these constructions exist if and only if arbitrary polynomial equations are decidable with respect to the underlying field. Besides such complexity theorems a variety of symbolic algorithms are discussed, and the methods are applied to obtain new mathematical results on convex polytopes, projective configurations and the combinatorics of Grassmann varieties. Finally algebraic varieties characterizing matroids and oriented matroids are introduced providing a new basis for applying computer algebra methods in this field. The necessary background knowledge is reviewed briefly. The text is accessible to students with graduate level background in mathematics, and will serve professional geometers and computer scientists as an introduction and motivation for further research. 180 pp. Englisch.

Taschenbuch. Condición: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -These notes give an account of recent work in harmonic analysis dealing with the analytical foundations of A. Weil's theory of metaplectic groups. It is shown that Weil's main theorem holds for a class of functions (a certain Segal algebra) larger than that of the Schwartz-Bruhat functions considered by Weil. The theorem is derived here from some general results about this class which seems to be a rather natural one in the context of Weil's theory. No previous knowledge of the latter is assumed, however, and the theory is developed here, step by step; Further, a complete discussion of the Segal algebra concerned is given, with references to the literature. Weil's metaplectic groups are somewhat easier to investigate when the characteristic is not 2; the case of characteristic 2 presents some special features which are fully discussed. New problems that arise are indicated. 148 pp. Englisch.

Taschenbuch. Condición: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware 176 pp. Englisch.

Taschenbuch. Condición: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -The latest in this series of Oberwolfach conferences focussed on the interplay between structural probability theory and various other areas of pure and applied mathematics such as Tauberian theory, infinite-dimensional rotation groups, central limit theorems, harmonizable processes, and spherical data. Thus it was attended by mathematicians whose research interests range from number theory to quantum physics in conjunction with structural properties of probabilistic phenomena. This volume contains 5 survey articles submitted on special invitation and 25 original research papers. 452 pp. Englisch, Französisch.

Taschenbuch. Condición: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -The programme of the Conference at El Escorial included 4 main courses of 3-4 hours. Their content is reflected in the four survey papers in this volume (see above). Also included are the ten 45-minute lectures of a more specialized nature. 224 pp. Englisch.

Taschenbuch. Condición: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -The 1st International Workshop in the Molecular and Cell Biology of Autoan tibodies and Autoimmunity is convened at a time when recombinant DNA tech niques have yielded the first set of data providing initial glimpses of epitopes recognized by autoantibodies. It's aim is to bring together cell and molecular biologists with clinical scien tists to discuss the broad spectrum of questions concerning the relationship be tween clinical symptoms and the specificity of autoantibodies. The response to the call for abstracts was overwhelming: Nearly one hundred abstracts were received from many laboratories throughout the world. The topics covered by them are representative of the current research efforts going on to study cause and effect of autoimmune diseases. One of the aims of this workshop is to bring the rapid advances in the elucidation of the molecular structure of auto antigens to the attention of immunologists, cell biologists and clinical scien tists and also to make molecular biologists bei6ple aware of the difficulties lying ahead in trying to understand the cellular and molecular basis of rheumatic dis eases. The organisers wish to thank NIH, BMFT and the Japanese Educational Foundation for financial support, the Heidelberg Academy for the Humanities and Sciences for hosting the workshop, Springer Verlag for their generous cooperation in including late abstracts in this volume, and, last not least, Ms. Simone KRAMBS for untiring secretarial help. 136 pp. Englisch.

Taschenbuch. Condición: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -Capacity is a measure of size for sets, with diverse applications in potential theory, probability and number theory. This book lays foundations for a theory of capacity for adelic sets on algebraic curves. Its main result is an arithmetic one, a generalization of a theorem of Fekete and Szegö which gives a sharp existence/finiteness criterion for algebraic points whose conjugates lie near a specified set on a curve. The book brings out a deep connection between the classical Green's functions of analysis and Néron's local height pairings; it also points to an interpretation of capacity as a kind of intersection index in the framework of Arakelov Theory. It is a research monograph and will primarily be of interest to number theorists and algebraic geometers; because of applications of the theory, it may also be of interest to logicians. The theory presented generalizes one due to David Cantor for the projective line. As with most adelic theories, it has a local and a global part. Let /K be a smooth, complete curve over a global field; let Kv denote the algebraic closure of any completion of K. The book first develops capacity theory over local fields, defining analogues of the classical logarithmic capacity and Green's functions for sets in (Kv). It then develops a global theory, defining the capacity of a galois-stable set in (Kv) relative to an effictive global algebraic divisor. The main technical result is the construction of global algebraic functions whose logarithms closely approximate Green's functions at all places of K. These functions are used in proving the generalized Fekete-Szegö theorem; because of their mapping properties, they may be expected to have other applications as well. 444 pp. Englisch.

Taschenbuch. Condición: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware 172 pp. Englisch.

Taschenbuch. Condición: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -Cost Analysis is an emerging sub-discipline of Economics and Operations Research. This is the first collection of readings that spans the discipline. The contributions are both theoretical and applications oriented. This book is directed to researchers in Economics, Operations Research, Industrial Engineering, and Managerial Accounting. In particular, the book provides an overview of the types of problems that are of interest to cost researchers. These papers are a subset of the papers that were presented at the 1989 Joint National Meeting of the Institute of Cost Analysis and the National Estimating Society in Washington, D.C. 436 pp. Englisch.

Taschenbuch. Condición: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -This volume contains the proceedings of the conference on Fundamentals of Computation Theory held in Szeged, Hungary, August 21-25, 1989. The conference is the seventh in the series of the FCT conferences initiated in 1977 in Poznan-Kornik, Poland. The papers collected in this volume are the texts of invited contributions and shorter communications falling into one of the following sections: - Efficient Computation by Abstract Devices: Automata, Computability, Probabilistic Computations, Parallel and Distributed Computing; - Logics and Meanings of Programs: Algebraic and Categorical Approaches to Semantics, Computational Logic, Logic Programming, Verification, Program Transformations, Functional Programming; - Formal Languages: Rewriting Systems, Algebraic Language Theory; - Computational Complexity: Analysis and Complexity of Algorithms, Design of Efficient Algorithms, Algorithms and Data Structures, Computational Geometry, Complexity Classes and Hierarchies, Lower Bounds. 516 pp. Englisch.

Taschenbuch. Condición: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -This book is the result of the research in the implementation of polygon-based graphics operations on certain general purpose parallel processors; the aim is to provide a speed-up over sequential implementations of the graphics operations concerned, and the resulting software can be viewed as a subset of the application suites of the relevant parallel machines. A literature review and a brief description of the architectures considered give an introduction into the field. Most algorithms are consistently presented in an informally defined extension of the Occam language which includes Single Instruction Multiple Data stream (SIMD) data types and operations on them. Original methods for polygon rendering - including the operations of filling, hidden surface elimination and smooth shading - are presented for SIMD architectures like the DAP and for a dual-paradigm (SIMD-MIMD) machine constructed out of a DAP-like processor array and a transputer network. Polygon clipping algorithms for both transputer and the DAP are described and contrasted. Apart from the information presented in the book and the useful literature survey, the reader can also expect to gain an insight into the programming of the relevant parallel machines. 160 pp. Englisch.

Taschenbuch. Condición: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -This book examines the pace of change and the nature of the Thatcherite revolution, 1983-87. It draws on 30 interviews with ministers and officials and offers a critique of existing theories of Thatcherism. The author assesses the progress of, opposition to and future of policy. 174 pp. Englisch.

Taschenbuch. Condición: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -This book aims to trace the life of the seventeenth-century Frenchwoman from cradle to the grave through mainly contemporary primary sources which include just about everything from collections of laws to traveller's tales. Rather than reworking and refuting the twentieth-century experts in the field, the author works directly through from birth and childhood through matrimony, women at work, and in political life, manners and religion to conclusive death. 440 pp. Englisch.

Buch. Condición: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware 176 pp. Englisch.

Taschenbuch. Condición: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -This supplement contains the papers submitted at EUROTOX 88, the joint Congress of the European Society of Toxicology and the Federation of the European Societies of Toxicology. The theme was one of monitoring and examining the effects of toxic substances in the biological response at the subcellular level. Mechanisms of metal carcinogenicity are discussed as well as the biomonitoring of chemical exposure. Reports are provided on the role of individual differences in man and the effect of risk assessment. Papers appear dealing with the genetic control of drug metabolizing enzymes. The role of metabolism in organic specific toxicity is discussed. Information is included on the toxicological impact of chemicals interfering with the endocrine system as well as on the effects of toxicants on the immune system. Presentations deal with the current status of risk assessment in environmental toxicology. 480 pp. Englisch.

Taschenbuch. Condición: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -This volume contains the proceedings of the 15th Spring School of the LITP (Laboratoire d'Informatique Théorique et de Programmation, Université Paris VI-VII, CNRS) held from May 25 to 29, 1987 in Saint-Pierre d'Oléron. The meeting was organized by M. Borillo, M. Gross, M. Nivat and D. Perrin. The purpose of this yearly meeting is to present the state of the art in a specific topic which has gained considerable maturity. The proceedings of the last three Spring Schools have already been published in this series and deal with 'Automata on Infinite Words' (LNCS 192), 'Combinators and Functional Programming Languages ' (LNCS 242) and 'Automata Networks' (LNCS 316). The contributions gathered for the 1987 conference present a unique combination of automata theory on the one hand and natural language processing on the other hand. Both fields have strong historical links as exemplified by the works of Chomsky and Harris in Linguistics, the work of Backus and others in Computer Science and the work of Schützenberger in Algebra. The methods described and discussed in the field of string processing and automata cover the traditional algorithms for string matching, data compression, sequence comparison and lexical analysis. The papers that deal more directly with natural language processing treat automated text generation, lexical analysis and formal representation. 120 pp. Englisch.

Taschenbuch. Condición: Neu. This item is printed on demand - Print on Demand Titel. Neuware -These notes give an account of recent work in harmonic analysis dealing with the analytical foundations of A. Weil's theory of metaplectic groups. It is shown that Weil's main theorem holds for a class of functions (a certain Segal algebra) larger than that of the Schwartz-Bruhat functions considered by Weil. The theorem is derived here from some general results about this class which seems to be a rather natural one in the context of Weil's theory. No previous knowledge of the latter is assumed, however, and the theory is developed here, step by step; Further, a complete discussion of the Segal algebra concerned is given, with references to the literature. Weil's metaplectic groups are somewhat easier to investigate when the characteristic is not 2; the case of characteristic 2 presents some special features which are fully discussed. New problems that arise are indicated.Springer-Verlag KG, Sachsenplatz 4-6, 1201 Wien 148 pp. Englisch.

Taschenbuch. Condición: Neu. This item is printed on demand - Print on Demand Titel. Neuware -Computational synthetic geometry deals with methods for realizing abstract geometric objects in concrete vector spaces. This research monograph considers a large class of problems from convexity and discrete geometry including constructing convex polytopes from simplicial complexes, vector geometries from incidence structures and hyperplane arrangements from oriented matroids. It turns out that algorithms for these constructions exist if and only if arbitrary polynomial equations are decidable with respect to the underlying field. Besides such complexity theorems a variety of symbolic algorithms are discussed, and the methods are applied to obtain new mathematical results on convex polytopes, projective configurations and the combinatorics of Grassmann varieties. Finally algebraic varieties characterizing matroids and oriented matroids are introduced providing a new basis for applying computer algebra methods in this field. The necessary background knowledge is reviewed briefly. The text is accessible to students with graduate level background in mathematics, and will serve professional geometers and computer scientists as an introduction and motivation for further research.Springer-Verlag KG, Sachsenplatz 4-6, 1201 Wien 180 pp. Englisch.