Anyone browsing at the stationery store will see an incredible array of pop-up cards available for any occasion. The workings of pop-up cards and pop-up books can be remarkably intricate. Behind such designs lies beautiful geometry involving the intersection of circles, cones, and spheres, the movements of linkages, and other constructions. The geometry can be modelled by algebraic equations, whose solutions explain the dynamics. For example, several pop-up motions rely on the intersection of three spheres, a computation made every second for GPS location. Connecting the motions of the card structures with the algebra and geometry reveals abstract mathematics performing tangible calculations. Beginning with the nephroid in the 19th-century, the mathematics of pop-up design is now at the frontiers of rigid origami and algorithmic computational complexity. All topics are accessible to those familiar with high-school mathematics; no calculus required. Explanations are supplemented by 140+ figures and 20 animations.

Following the highly successful first edition, this text deals with numerical solutions of coupled thermo-hydro-mechanical problems in porous media. Governing equations are newly derived in a general form using both averaging methods (hybrid mixture theory) and an engineering approach. Unique new features of the book include numerical solutions for fully and partially saturated consolidation, subsidence analysis including far field boundary conditions (Infinite Elements), new case studies and also petroleum reservoir simulation. Extended heat and mass transfer in partially saturated porous media, and consideration of phase change, are covered in detail. In addition, large strain, fully and partially saturated, soil dynamics problems are explained. Back analysis for consolidation problems is also included. Significantly, the reader is provided with access to a Finite Element code for coupled thermo-hydro-mechanical problems in partially saturated porous media with full two phase flow and phase change, written according to the theory outlined in the book and obtainable via the Network of the Italian Research Council (COMES). With a range of engineering applications from geotechnical and petroleum engineering through to bioengineering and materials science, this book represents an important resource for students, researchers and practising engineers in all these and related fields.

A practical, accessible introduction to advanced geometry

Exceptionally well-written and filled with historical and bibliographic notes, Methods of Geometry presents a practical and proof-oriented approach. The author develops a wide range of subject areas at an intermediate level and explains how theories that underlie many fields of advanced mathematics ultimately lead to applications in science and engineering. Foundations, basic Euclidean geometry, and transformations are discussed in detail and applied to study advanced plane geometry, polyhedra, isometries, similarities, and symmetry. An excellent introduction to advanced concepts as well as a reference to techniques for use in independent study and research, Methods of Geometry also features:

• Ample exercises designed to promote effective problem-solving strategies
• Insight into novel uses of Euclidean geometry
• More than 300 figures accompanying definitions and proofs
• A comprehensive and annotated bibliography
• Appendices reviewing vector and matrix algebra, least upper bound principle, and equivalence relations

Written for graduate students, this book presents topics in 2-dimensional hyperbolic geometry. The authors begin with rigid motions in the plane which are used as motivation for a full development of hyperbolic geometry in the unit disk. The approach is to define metrics from an infinitesimal point of view; first the density is defined and then the metric via integration. The study of hyperbolic geometry in arbitrary domains requires the concepts of surfaces and covering spaces as well as uniformization and Fuchsian groups. These ideas are developed in the context of what is used later. The authors then provide a detailed discussion of hyperbolic geometry for arbitrary plane domains. New material on hyperbolic and hyperbolic-like metrics is presented. These are generalizations of the Kobayashi and Caratheodory metrics for plane domains. The book concludes with applications to holomorphic dynamics including new results and accessible open problems.

This volume consists of the refereed proceedings of the Japan Conference on Discrete and Computational Geometry (JCDCG 2004) held at Tokai University in Tokyo, Japan, October, 8-11, 2004, to honor Jan ' os Pach on his 50th year. J' anos Pach has generously supported the e?orts to promote research in discrete and computational geometry among mathematicians in Asia for many years. The conference was attended by close to 100 participants from 20 countries. Since it was ?rst organized in 1997, the annual JCDCG has attracted a growing international participation. The earlier conferences were held in Tokyo, followed by conferences in Manila, Philippines, and Bandung, Indonesia. The proceedings of JCDCG 1998, 2000, 2002 and IJCCGGT 2003 were published by SpringeraspartoftheseriesLectureNotesinComputerScience(LNCS)volumes 1763, 2098, 2866 and 3330, respectively, while the proceedings of JCDCG 2001 were also published by Springer as a special issue of the journal Graphs and Combinatorics, Vol. 18, No. 4, 2002. The organizers of JCDCG 2004 gratefully acknowledge the sponsorship of Tokai University, the support of the conference secretariat and the partici- tion of the principal speakers: Ferran Hurtado, Hiro Ito, Alberto M' arquez, Ji? r' ? Matou? sek, Ja 'nos Pach, Jonathan Shewchuk, William Steiger, Endre Szemer' edi, G' eza T' oth, Godfried Toussaint and Jorge Urrutia.

The origins of the word problem are in group theory, decidability and complexity. But through the vision of M. Gromov and the language of filling functions, the topic now impacts the world of large-scale geometry. This book contains accounts of many recent developments in Geometric Group Theory and shows the interaction between the word problem and geometry continues to be a central theme. It contains many figures, numerous exercises and open questions.

Fractalize That! A Visual Essay on Statistical Geometry brings a new class of geometric fractals to a wider audience of mathematicians and scientists. It describes a recently discovered random fractal space-filling algorithm. Connections with tessellations and known fractals such as Sierpinski are developed. And, the mathematical development is illustrated by a large number of colorful images that will charm the readers.The algorithm claims to be universal in scope, in that it can fill any spatial region with smaller and smaller fill regions of any shape. The filling is complete in the limit of an infinite number of fill regions. This book presents a descriptive development of the subject using the traditional shapes of geometry such as discs, squares, and triangles. It contains a detailed mathematical treatment of all that is currently known about the algorithm, as well as a chapter on software implementation of the algorithm.The mathematician will find a wealth of interesting conjectures supported by numerical computation. Physicists are offered a model looking for an application. The patterns generated are often quite interesting as abstract art. Readers can also create these computer-generated art with the advice and examples provided.

This introduction to the theory of rigid structures explains how to analyze the performance of built and natural structures under loads, paying special attention to the role of geometry. The book unifies the engineering and mathematical literatures by exploring different notions of rigidity - local, global, and universal - and how they are interrelated. Important results are stated formally, but also clarified with a wide range of revealing examples. An important generalization is to tensegrities, where fixed distances are replaced with 'cables' not allowed to increase in length and 'struts' not allowed to decrease in length. A special feature is the analysis of symmetric tensegrities, where the symmetry of the structure is used to simplify matters and allows the theory of group representations to be applied. Written for researchers and graduate students in structural engineering and mathematics, this work is also of interest to computer scientists and physicists.

Focusing on the manipulation and representation of geometrical objects, this book explores the application of geometry to computer graphics and computer-aided design (CAD). Over 300 exercises are included, some new to this edition, and many of which encourage the reader to implement the techniques and algorithms discussed through the use of a computer package with graphing and computer algebra capabilities. A dedicated website also offers further resources and useful links.

In 19 articles presented by leading experts in the field of geometric modelling the state-of-the-art on representing, modeling, and analyzing curves, surfaces as well as other 3-dimensional geometry is given. The range of applications include CAD/CAM-systems, computer graphics, scientific visualization, virtual reality, simulation and medical imaging. The content of this book is based on selected lectures given at a workshop held at IBFI Schloss Dagstuhl, Germany. Topics treated are: - curve and surface modelling - non-manifold modelling in CAD - multiresolution analysis of complex geometric models - surface reconstruction - variational design - computational geometry of curves and surfaces - 3D meshing - geometric modelling for scientific visualization - geometric models for biomedical applications

This new edition of Six Simple Twists: The Pleat Pattern Approach to Origami Tessellation Design introduces an innovative pleat pattern technique for origami designs that is easily accessible to anyone who enjoys the geometry of paper. The book begins with six basic forms meant to ease the reader into the style, and then systematically scaffolds the instructions to build a strong understanding of the techniques, leading to instructions on a limitless number of patterns. It then describes a process of designing additional building blocks. At the end, what emerges is a fascinating artform that will enrich folders for many years. Unlike standard, project-based origami books, Six Simple Twists focuses on how to design, rather than construct. In this thoroughly updated second edition, the book explores new techniques and example tessellations, with full-page images, and mathematical analysis of the patterns. A reader will, through practice, gain the ability to create still more complex and fascinating designs. Key Features Introduces the reader to origami tessellations and demonstrates their place in the origami community New layout and instructional approach restructure the book from the ground up Addresses common tessellation questions, such as what types of paper are best to use, and how this artform rose in popularity Teaches the reader how to grid a sheet of paper and the importance of the pre-creases Gives the reader the ability to create and understand tessellations through scaffolded instruction Includes exercises to test understanding Introduces a new notation system for precisely describing pleat intersections Analyzes pleat intersections mathematically using geometrically-focused models, including information about Brocard points

New variational methods by Aubry, Mather, and Mane, discovered in the last twenty years, gave deep insight into the dynamics of convex Lagrangian systems. This book shows how this Principle of Least Action appears in a variety of settings (billiards, length spectrum, Hofer geometry, modern symplectic geometry). Thus, topics from modern dynamical systems and modern symplectic geometry are linked in a new and sometimes surprising way. The central object is Mather 's minimal action functional. The level is for graduate students onwards, but also for researchers in any of the subjects touched in the book.

Algebraic projective geometry, with its multilinear relations and its embedding into Grassmann-Cayley algebra, has become the basic representation of multiple view geometry, resulting in deep insights into the algebraic structure of geometric relations, as well as in efficient and versatile algorithms for computer vision and image analysis.

This book provides a coherent integration of algebraic projective geometry and spatial reasoning under uncertainty with applications in computer vision. Beyond systematically introducing the theoretical foundations from geometry and statistics and clear rules for performing geometric reasoning under uncertainty, the author provides a collection of detailed algorithms.

The book addresses researchers and advanced students interested in algebraic projective geometry for image analysis, in statistical representation of objects and transformations, or in generic tools for testing and estimating within the context of geometric multiple-view analysis.

In recent years, geometry has played a lesser role in undergraduate courses than it has ever done. Nevertheless, it still plays a leading role in mathematics at a higher level. Its central role in the history of mathematics has never been disputed. It is important, therefore, to introduce some geometry into university syllabuses. There are several ways of doing this, it can be incorporated into existing courses that are primarily devoted to other topics, it can be taught at a first year level or it can be taught in higher level courses devoted to differential geometry or to more classical topics. These notes are intended to fill a rather obvious gap in the literature. It treats the classical topics of Euclidean, projective and hyperbolic geometry but uses the material commonly taught to undergraduates: linear algebra, group theory, metric spaces and complex analysis. The notes are based on a course whose aim was two fold, firstly, to introduce the students to some geometry and secondly to deepen their understanding of topics that they have already met. What is required from the earlier material is a familiarity with the main ideas, specific topics that are used are usually redone.

Among the intuitively appealing aspects of graph theory is its close connection to drawings and geometry. The development of computer technology has become a source of motivation to reconsider these connections, in particular geometric graphs are emerging as a new subfield of graph theory. Arrangements of points and lines are the objects for many challenging problems and surprising solutions in combinatorial geometry. The book is a collection of beautiful and partly very recent results from the intersection of geometry, graph theory and combinatorics.

This book constitutes the thoroughly refereed post-proceedings of the 4th International Workshop on Automated Deduction in Geometry, ADG 2002, held at Hagenberg Castle, Austria in September 2002.

The 13 revised full papers presented were carefully selected during two rounds of reviewing and improvement. Among the issues addressed are theoretical and methodological topics, such as the resolution of singularities, algebraic geometry and computer algebra; various geometric theorem proving systems are explored; and applications of automated deduction in geometry are demonstrated in fields like computer-aided design and robotics.

The Morse-Sard theorem is a rather subtle result and the interplay between the high-order analytic structure of the mappings involved and their geometry rarely becomes apparent. The main reason is that the classical Morse-Sard theorem is basically qualitative. This volume gives a proof and also an "explanation" of the quantitative Morse-Sard theorem and related results, beginning with the study of polynomial (or tame) mappings. The quantitative questions, answered by a combination of the methods of real semialgebraic and tame geometry and integral geometry, turn out to be nontrivial and highly productive. The important advantage of this approach is that it allows the separation of the role of high differentiability and that of algebraic geometry in a smooth setting: all the geometrically relevant phenomena appear already for polynomial mappings. The geometric properties obtained are "stable with respect to approximation," and can be imposed on smooth functions via polynomial approximation.

A complete, self-contained introduction to a powerful and resurging mathematical discipline … Combinatorial Geometry presents and explains with complete proofs some of the most important results and methods of this relatively young mathematical discipline, started by Minkowski, Fejes Tóth, Rogers, and Erd???s. Nearly half the results presented in this book were discovered over the past twenty years, and most have never before appeared in any monograph. Combinatorial Geometry will be of particular interest to mathematicians, computer scientists, physicists, and materials scientists interested in computational geometry, robotics, scene analysis, and computer-aided design. It is also a superb textbook, complete with end-of-chapter problems and hints to their solutions that help students clarify their understanding and test their mastery of the material. Topics covered include:

• Geometric number theory
• Packing and covering with congruent convex disks
• Extremal graph and hypergraph theory
• Distribution of distances among finitely many points
• Epsilon-nets and Vapnik—Chervonenkis dimension
• Geometric graph theory
• Geometric discrepancy theory
• And much more

Broad appeal to undergraduate teachers, students, and engineers; Concise descriptions of properties of basic planar curves from different perspectives; useful handbook for software engineers; A special chapter---"Geometry on the Web"---will further enhance the usefulness of this book as an informal tutorial resource.; Good mathematical notation, descriptions of properties of lines and curves, and the illustration of geometric concepts facilitate the design of computer graphics tools and computer animation.; Video game designers, for example, will find a clear discussion and illustration of hard-to-understand trajectory design concepts.; Good supplementary text for geometry courses at the undergraduate and advanced high school levels

This book is based on the author's experience with calculations involving polynomial splines. It presents those parts of the theory which are especially useful in calculations and stresses the representation of splines as linear combinations of B-splines. After two chapters summarizing polynomial approximation, a rigorous discussion of elementary spline theory is given involving linear, cubic and parabolic splines. The computational handling of piecewise polynomial functions (of one variable) of arbitrary order is the subject of chapters VII and VIII, while chapters IX, X, and XI are devoted to B-splines. The distances from splines with fixed and with variable knots is discussed in chapter XII. The remaining five chapters concern specific approximation methods, interpolation, smoothing and least-squares approximation, the solution of an ordinary differential equation by collocation, curve fitting, and surface fitting. The present text version differs from the original in several respects. The book is now typeset (in plain TeX), the Fortran programs now make use of Fortran 77 features. The figures have been redrawn with the aid of Matlab, various errors have been corrected, and many more formal statements have been provided with proofs. Further, all formal statements and equations have been numbered by the same numbering system, to make it easier to find any particular item. A major change has occured in Chapters IX-XI where the B-spline theory is now developed directly from the recurrence relations without recourse to divided differences. This has brought in knot insertion as a powerful tool for providing simple proofs concerning the shape-preserving properties of the B-spline series.

Since it was ?rst organized in 1997, the Japan Conference on Discrete and C- putational Geometry (JCDCG) continues to attract an international audience. The ?rst ?ve conferences of the series were held in Tokyo, the sixth in Manila, Philippines. This volume consists of the refereed papers presented at the seventh conference, JCDCG 2002, held in Tokai University, Tokyo, December 6-9, 2002. An eighth conference is planned to be held in Bandung, Indonesia. The proceedings of JCDCG 1998 and JCDCG 2000 were published by Springer-Verlag as part of the series Lecture Notes in Computer Science: LNCS volumes 1763 and 2098, respectively. The proceedings of JCDCG 2001 were also published by Springer-Verlag as a special issue of the journal Graphs and C- binatorics, Vol. 18, No. 4, 2002. The organizers are grateful to Tokai University for sponsoring the conf- ence. They wish to thank all the people who contributed to the success of the conference, in particular, Chie Nara, who headed the conference secretariat, and the principal speakers: Takao Asano, David Avis, Greg N. Frederickson, Ferran Hurtado, Joseph O'Rourke, J anos Pach, Rom Pinchasi, and Jorge Urrutia."

The new edition of this non-mathematical review of catastrophe theory contains updated results and many new or expanded topics including delayed loss of stability, shock waves, and interior scattering. Three new sections offer the history of singularity and its applications from da Vinci to today, a discussion of perestroika in terms of the theory of metamorphosis, and a list of 93 problems touching on most of the subject matter in the book.

This proceedings volume includes papers presented at DGCI 2003 in Naples, Italy, November 19-21, 2003. DGCI 2003 was the 11th conference in a series of internationalconferencesonDiscreteGeometryforComputerImagery.Thec- ference was organized by the Italian Institute for Philosophical Studies, Naples and the Institute of Cybernetics "E. Caianiello," National Research Council of Italy, Pozzuoli (Naples). DGCI 2003 was sponsored by the International Asso- ation for Pattern Recognition (IAPR). ThisisthesecondtimetheconferencetookplaceoutsideFrance.Thenumber ofresearchersactiveinthe?eldofdiscretegeometryandcomputerimageryis- creasing. Both these factors contribute to the increased international recognition of the conference. The DGCI conferences attract more and more academic and research institutions in di?erent countries. In fact, 68 papers were submitted to DGCI2003.Thecontributionsfocusondiscretegeometryandtopology, surfaces and volumes, morphology, shape representation, and shape analysis. After ca- ful reviewing by an international board of reviewers, 23 papers were selected for oral presentation and 26 for poster presentation. All contributions were sch- uled in plenary sessions. In addition, the program was enriched by three l- tures, presented by internationally well-known invited speakers: Isabelle Bloch (EcoleNationaleSup erieuredesT el ecommunications, France), LonginJanLa- cki(TempleUniversity, USA), andRalphKopperman(CityCollegeofNewYork, USA). In 2002, a technical committee of the IAPR, TC18, was established with the intention to promote interactions and collaboration between researchers wo- ing on discrete geometry. The ?rst TC18 meeting was planned to be held in conjunction with DGCI 2003, to allow the members to discuss the activity of the technical committee. The outcome from this meeting will help the ongoing research and communication for researchers active within the ?eld during the 18 months between the conferences."

This text, written by established mathematicians and physicists, provides a systematic, unified exposition of Clifford (geometric) algebras. Beginning with an introductory chapter, the book covers the mathematical structure of Clifford algebras and the basic concepts of Clifford analysis, and then provides a detailed examination of the many applications of Clifford algebras to differential geometry, physics, computer vision and robotics. No prior knowledge of the subject is assumed. The book 's breadth will appeal to graduate students and researchers in mathematics, physics, and engineering.

Contents: P. Lounesto, Introduction to Clifford Algebras; I. Porteous, Mathematical Structure of Clifford Algebras; J. Ryan, Clifford Analysis; W. Baylis, Applications of Clifford Algebras in Physics; J. Selig, Clifford Algebras in Engineering; T. Branson, Clifford Bundles and Clifford Algebras; R. Ablamowicz and G. Sobczyk, Appendix: Software for Clifford (Geometric) Algebras

Manifolds are the central geometric objects in modern mathematics. An attempt to understand the nature of manifolds leads to many interesting questions. One of the most obvious questions is the following. Let M and N be manifolds: how can we decide whether M and N are ho- topy equivalent or homeomorphic or di?eomorphic (if the manifolds are smooth)? The prototype of a beautiful answer is given by the Poincar e Conjecture. If n N is S, the n-dimensional sphere, and M is an arbitrary closed manifold, then n it is easy to decide whether M is homotopy equivalent to S . Thisisthecaseif and only if M is simply connected (assumingn> 1, the case n = 1 is trivial since 1 every closed connected 1-dimensional manifold is di?eomorphic toS ) and has the n homology of S . The PoincareConjecture states that this is also su?cient for the n existenceof ahomeomorphism fromM toS . For n = 2this followsfromthewe- known classi?cation of surfaces. Forn> 4 this was proved by Smale and Newman in the 1960s, Freedman solved the case in n = 4 in 1982 and recently Perelman announced a proof for n = 3, but this proof has still to be checked thoroughly by the experts. In the smooth category it is not true that manifolds homotopy n equivalent to S are di?eomorphic. The ?rst examples were published by Milnor in 1956 and together with Kervaire he analyzed the situation systematically in the 1960s."