Contents. Preface... VII. Part I Classical Topics Revisited

Size: px
Start display at page:

Download "Contents. Preface... VII. Part I Classical Topics Revisited"

Transcription

1 Contents Preface VII Part I Classical Topics Revisited 1 Sphere Packings Kissing Numbers of Spheres One-Sided Kissing Numbers of Spheres On the Contact Numbers of Finite Sphere Packings Lower Bounds for the (Surface) Volume of Voronoi Cells in Sphere Packings On the Density of Sphere Packings in Spherical Containers Upper Bounds on Sphere Packings in High Dimensions Uniform Stability of Sphere Packings Finite Packings by Translates of Convex Bodies Hadwiger Numbers of Convex Bodies One-Sided Hadwiger Numbers of Convex Bodies Touching Numbers of Convex Bodies On the Number of Touching Pairs in Finite Packings Coverings by Homothetic Bodies - Illumination and Related Topics The Illumination Conjecture Equivalent Formulations The Illumination Conjecture in Dimension Three The Illumination Conjecture in High Dimensions On the X-Ray Number of Convex Bodies The Successive Illumination Numbers of Convex Bodies The Illumination and Covering Parameters of Convex Bodies On the Vertex Index of Convex Bodies

2 X Contents 4 Coverings by Planks and Cylinders Plank Theorems Covering Convex Bodies by Cylinders Covering Lattice Points by Hyperplanes On Some Strengthenings of the Plank Theorems of Ball and Bang On Partial Coverings by Planks: Bang s Theorem Revisited On the Volume of Finite Arrangements of Spheres The Conjecture of Kneser and Poulsen The Kneser Poulsen Conjecture for Continuous Contractions The Kneser Poulsen Conjecture in the Plane Non-Euclidean Kneser Poulsen-Type Results Alexander s Conjecture Densest Finite Sphere Packings Ball-Polyhedra as Intersections of Congruent Balls Disk-Polygons and Ball-Polyhedra Shortest Billiard Trajectories in Disk-Polygons Blaschke Lebesgue-Type Theorems for Disk-Polygons On the Steinitz Problem for Ball-Polyhedra On Global Rigidity of Ball-Polyhedra Separation and Support for Spindle Convex Sets Carathéodory- and Steinitz-Type Results Illumination of Ball-Polyhedra The Euler Poincaré Formula for Ball-Polyhedra Part II Selected Proofs 7 Selected Proofs on Sphere Packings Proof of Theorem A proof by estimating the surface area of unions of balls On the densest packing of congruent spherical caps of special radius Proof of Theorem The Voronoi star of a Voronoi cell in unit ball packings Estimating the volume of a Voronoi star from below Proof of Theorem Basic metric properties of Voronoi cells in unit ball packings Wedges of types I, II, and III, and truncated wedges of types I, and II The lemma of comparison and a characterization of regular polytopes

3 Contents XI Volume formulas for (truncated) wedges The integral representation of surface density in (truncated) wedges Truncation of wedges increases the surface density Maximum surface density in truncated wedges of type I An upper bound for the surface density in truncated wedges of type II The overall estimate of surface density in Voronoi cells Proof of Theorem The signed volume of convex polytopes The volume force of convex polytopes Critical volume condition Strictly locally volume expanding convex polytopes From critical volume condition and infinitesimal rigidity to uniform stability of sphere packings Selected Proofs on Finite Packings of Translates of Convex Bodies Proof of Theorem Monotonicity of a special integral function A proof by slicing via the Brunn Minkowski inequality Proof of Theorem Selected Proofs on Illumination and Related Topics Proof of Corollary Using Rogers Classical Theorem on Economical Coverings Proof of Theorem via the Gauss Map Proof of Theorem Using Antipodal Spherical Codes of Small Covering Radii Proofs of Theorem and Theorem From the Banach Mazur distance to the vertex index Calculating the vertex index of Euclidean balls in dimensions 2 and A lower bound for the vertex index using the Blaschke Santaló inequality and an inequality of Ball and Pajor An upper bound for the vertex index using a theorem of Rudelson Selected Proofs on Coverings by Planks and Cylinders Proof of Theorem On coverings of convex bodies by two planks A proof of the affine plank conjecture of Bang for non-overlapping cuts Proof of Theorem

4 XII Contents Covering ellipsoids by 1-codimensional cylinders Covering convex bodies by cylinders of given codimension Proof of Theorem Proof of Theorem Selected Proofs on the Kneser Poulsen Conjecture Proof of Theorem on the Monotonicity of Weighted Surface Volume Proof of Theorem on Weighted Surface and Codimension Two Volumes Proof of Theorem the Leapfrog Lemma Proof of Theorem The spherical leapfrog lemma Smooth contractions via Schläfli s differential formula Relating higher-dimensional spherical volumes to lower-dimensional ones Putting pieces together Proof of Theorem Monotonicity of the volume of hyperbolic simplices From Andreev s theorem to smooth one-parameter family of hyperbolic polyhedra Selected Proofs on Ball-Polyhedra Proof of Theorem Finite sets that cannot be translated into the interior of a convex body From generalized billiard trajectories to shortest ones Proofs of Theorems 6.6.1, 6.6.3, and Strict separation by spheres of radii at most one Characterizing spindle convex sets Separating spindle convex sets Proof of Theorem On the boundary of spindle convex hulls in terms of supporting spheres From the spherical Carathéodory theorem to an analogue for spindle convex hulls Proof of Theorem On the boundary of spindle convex hulls in terms of normal images On the Euclidean diameter of spindle convex hulls and normal images An upper bound for the illumination number based on a probabilistic approach

5 Contents XIII Schramm s lower bound for the proper measure of polars of sets of given diameter in spherical space An upper bound for the number of sets of given diameter that are needed to cover spherical space The final upper bound for the illumination number Proof of Theorem The CW-decomposition of the boundary of a standard ball-polyhedron On the number of generating balls of a standard ball-polyhedron Basic properties of face lattices of standard ball-polyhedra References

6

A Course in Convexity

A Course in Convexity A Course in Convexity Alexander Barvinok Graduate Studies in Mathematics Volume 54 American Mathematical Society Providence, Rhode Island Preface vii Chapter I. Convex Sets at Large 1 1. Convex Sets. Main

More information

ACTUALLY DOING IT : an Introduction to Polyhedral Computation

ACTUALLY DOING IT : an Introduction to Polyhedral Computation ACTUALLY DOING IT : an Introduction to Polyhedral Computation Jesús A. De Loera Department of Mathematics Univ. of California, Davis http://www.math.ucdavis.edu/ deloera/ 1 What is a Convex Polytope? 2

More information

We have set up our axioms to deal with the geometry of space but have not yet developed these ideas much. Let s redress that imbalance.

We have set up our axioms to deal with the geometry of space but have not yet developed these ideas much. Let s redress that imbalance. Solid geometry We have set up our axioms to deal with the geometry of space but have not yet developed these ideas much. Let s redress that imbalance. First, note that everything we have proven for the

More information

COMP331/557. Chapter 2: The Geometry of Linear Programming. (Bertsimas & Tsitsiklis, Chapter 2)

COMP331/557. Chapter 2: The Geometry of Linear Programming. (Bertsimas & Tsitsiklis, Chapter 2) COMP331/557 Chapter 2: The Geometry of Linear Programming (Bertsimas & Tsitsiklis, Chapter 2) 49 Polyhedra and Polytopes Definition 2.1. Let A 2 R m n and b 2 R m. a set {x 2 R n A x b} is called polyhedron

More information

Chapter 4 Concepts from Geometry

Chapter 4 Concepts from Geometry Chapter 4 Concepts from Geometry An Introduction to Optimization Spring, 2014 Wei-Ta Chu 1 Line Segments The line segment between two points and in R n is the set of points on the straight line joining

More information

Planar Graphs. 1 Graphs and maps. 1.1 Planarity and duality

Planar Graphs. 1 Graphs and maps. 1.1 Planarity and duality Planar Graphs In the first half of this book, we consider mostly planar graphs and their geometric representations, mostly in the plane. We start with a survey of basic results on planar graphs. This chapter

More information

Discrete geometry. Lecture 2. Alexander & Michael Bronstein tosca.cs.technion.ac.il/book

Discrete geometry. Lecture 2. Alexander & Michael Bronstein tosca.cs.technion.ac.il/book Discrete geometry Lecture 2 Alexander & Michael Bronstein tosca.cs.technion.ac.il/book Numerical geometry of non-rigid shapes Stanford University, Winter 2009 The world is continuous, but the mind is discrete

More information

Edge unfolding Cut sets Source foldouts Proof and algorithm Complexity issues Aleksandrov unfolding? Unfolding polyhedra.

Edge unfolding Cut sets Source foldouts Proof and algorithm Complexity issues Aleksandrov unfolding? Unfolding polyhedra. Unfolding polyhedra Ezra Miller University of Minnesota ezra@math.umn.edu University of Nebraska 27 April 2007 Outline 1. Edge unfolding 2. Cut sets 3. Source foldouts 4. Proof and algorithm 5. Complexity

More information

Math 414 Lecture 2 Everyone have a laptop?

Math 414 Lecture 2 Everyone have a laptop? Math 44 Lecture 2 Everyone have a laptop? THEOREM. Let v,...,v k be k vectors in an n-dimensional space and A = [v ;...; v k ] v,..., v k independent v,..., v k span the space v,..., v k a basis v,...,

More information

Curves and Fractal Dimension

Curves and Fractal Dimension Claude Tricot Curves and Fractal Dimension With a Foreword by Michel Mendes France With 163 Illustrations Springer-Verlag New York Berlin Heidelberg London Paris Tokyo Hong Kong Barcelona Budapest Contents

More information

maximize c, x subject to Ax b,

maximize c, x subject to Ax b, Lecture 8 Linear programming is about problems of the form maximize c, x subject to Ax b, where A R m n, x R n, c R n, and b R m, and the inequality sign means inequality in each row. The feasible set

More information

THEORY OF LINEAR AND INTEGER PROGRAMMING

THEORY OF LINEAR AND INTEGER PROGRAMMING THEORY OF LINEAR AND INTEGER PROGRAMMING ALEXANDER SCHRIJVER Centrum voor Wiskunde en Informatica, Amsterdam A Wiley-Inter science Publication JOHN WILEY & SONS^ Chichester New York Weinheim Brisbane Singapore

More information

CAT(0)-spaces. Münster, June 22, 2004

CAT(0)-spaces. Münster, June 22, 2004 CAT(0)-spaces Münster, June 22, 2004 CAT(0)-space is a term invented by Gromov. Also, called Hadamard space. Roughly, a space which is nonpositively curved and simply connected. C = Comparison or Cartan

More information

Patterned Triply Periodic Polyhedra

Patterned Triply Periodic Polyhedra Patterned Triply Periodic Polyhedra Douglas Dunham Department of Computer Science University of Minnesota, Duluth Duluth, MN 55812-3036, USA E-mail: ddunham@d.umn.edu Web Site: http://www.d.umn.edu/ ddunham/

More information

Triangles and Squares David Eppstein, ICS Theory Group, April 20, 2001

Triangles and Squares David Eppstein, ICS Theory Group, April 20, 2001 Triangles and Squares David Eppstein, ICS Theory Group, April 20, 2001 Which unit-side-length convex polygons can be formed by packing together unit squares and unit equilateral triangles? For instance

More information

FACES OF CONVEX SETS

FACES OF CONVEX SETS FACES OF CONVEX SETS VERA ROSHCHINA Abstract. We remind the basic definitions of faces of convex sets and their basic properties. For more details see the classic references [1, 2] and [4] for polytopes.

More information

Convex Geometry arising in Optimization

Convex Geometry arising in Optimization Convex Geometry arising in Optimization Jesús A. De Loera University of California, Davis Berlin Mathematical School Summer 2015 WHAT IS THIS COURSE ABOUT? Combinatorial Convexity and Optimization PLAN

More information

Week 7 Convex Hulls in 3D

Week 7 Convex Hulls in 3D 1 Week 7 Convex Hulls in 3D 2 Polyhedra A polyhedron is the natural generalization of a 2D polygon to 3D 3 Closed Polyhedral Surface A closed polyhedral surface is a finite set of interior disjoint polygons

More information

Convexity: an introduction

Convexity: an introduction Convexity: an introduction Geir Dahl CMA, Dept. of Mathematics and Dept. of Informatics University of Oslo 1 / 74 1. Introduction 1. Introduction what is convexity where does it arise main concepts and

More information

Lecture 3. Corner Polyhedron, Intersection Cuts, Maximal Lattice-Free Convex Sets. Tepper School of Business Carnegie Mellon University, Pittsburgh

Lecture 3. Corner Polyhedron, Intersection Cuts, Maximal Lattice-Free Convex Sets. Tepper School of Business Carnegie Mellon University, Pittsburgh Lecture 3 Corner Polyhedron, Intersection Cuts, Maximal Lattice-Free Convex Sets Gérard Cornuéjols Tepper School of Business Carnegie Mellon University, Pittsburgh January 2016 Mixed Integer Linear Programming

More information

Ec 181: Convex Analysis and Economic Theory

Ec 181: Convex Analysis and Economic Theory Division of the Humanities and Social Sciences Ec 181: Convex Analysis and Economic Theory KC Border Winter 2018 v. 2018.03.08::13.11 src: front KC Border: for Ec 181, Winter 2018 Woe to the author who

More information

However, this is not always true! For example, this fails if both A and B are closed and unbounded (find an example).

However, this is not always true! For example, this fails if both A and B are closed and unbounded (find an example). 98 CHAPTER 3. PROPERTIES OF CONVEX SETS: A GLIMPSE 3.2 Separation Theorems It seems intuitively rather obvious that if A and B are two nonempty disjoint convex sets in A 2, then there is a line, H, separating

More information

Example: The following is an example of a polyhedron. Fill the blanks with the appropriate answer. Vertices:

Example: The following is an example of a polyhedron. Fill the blanks with the appropriate answer. Vertices: 11.1: Space Figures and Cross Sections Polyhedron: solid that is bounded by polygons Faces: polygons that enclose a polyhedron Edge: line segment that faces meet and form Vertex: point or corner where

More information

Chapter 11 Part 2. Measurement of Figures and Solids

Chapter 11 Part 2. Measurement of Figures and Solids Chapter 11 Part 2 Measurement of Figures and Solids 11.5 Explore Solids Objective: Identify Solids Essential Question: When is a solid a polyhedron? Using properties of polyhedra A is a solid that is bounded

More information

Rigidity of ball-polyhedra via truncated Voronoi and Delaunay complexes

Rigidity of ball-polyhedra via truncated Voronoi and Delaunay complexes !000111! NNNiiinnnttthhh IIInnnttteeerrrnnnaaatttiiiooonnnaaalll SSSyyymmmpppooosssiiiuuummm ooonnn VVVooorrrooonnnoooiii DDDiiiaaagggrrraaammmsss iiinnn SSSccciiieeennnccceee aaannnddd EEEnnngggiiinnneeeeeerrriiinnnggg

More information

(1) Page #2 26 Even. (2) Page 596 #1 14. (3) Page #15 25 ; FF #26 and 28. (4) Page 603 #1 18. (5) Page #19 26

(1) Page #2 26 Even. (2) Page 596 #1 14. (3) Page #15 25 ; FF #26 and 28. (4) Page 603 #1 18. (5) Page #19 26 Geometry/Trigonometry Unit 10: Surface Area and Volume of Solids Notes Name: Date: Period: # (1) Page 590 591 #2 26 Even (2) Page 596 #1 14 (3) Page 596 597 #15 25 ; FF #26 and 28 (4) Page 603 #1 18 (5)

More information

CS675: Convex and Combinatorial Optimization Spring 2018 Convex Sets. Instructor: Shaddin Dughmi

CS675: Convex and Combinatorial Optimization Spring 2018 Convex Sets. Instructor: Shaddin Dughmi CS675: Convex and Combinatorial Optimization Spring 2018 Convex Sets Instructor: Shaddin Dughmi Outline 1 Convex sets, Affine sets, and Cones 2 Examples of Convex Sets 3 Convexity-Preserving Operations

More information

Math 210 Manifold III, Spring 2018 Euler Characteristics of Surfaces Hirotaka Tamanoi

Math 210 Manifold III, Spring 2018 Euler Characteristics of Surfaces Hirotaka Tamanoi Math 210 Manifold III, Spring 2018 Euler Characteristics of Surfaces Hirotaka Tamanoi 1. Euler Characteristic of Surfaces Leonhard Euler noticed that the number v of vertices, the number e of edges and

More information

66 III Complexes. R p (r) }.

66 III Complexes. R p (r) }. 66 III Complexes III.4 Alpha Complexes In this section, we use a radius constraint to introduce a family of subcomplexes of the Delaunay complex. These complexes are similar to the Čech complexes but differ

More information

An Introduction to Geometrical Probability

An Introduction to Geometrical Probability An Introduction to Geometrical Probability Distributional Aspects with Applications A. M. Mathai McGill University Montreal, Canada Gordon and Breach Science Publishers Australia Canada China Prance Germany

More information

Gauss images of hyperbolic cusps with convex polyhedral boundary

Gauss images of hyperbolic cusps with convex polyhedral boundary Gauss images of hyperbolic cusps with convex polyhedral boundary François Fillastre, Ivan Izmestiev To cite this version: François Fillastre, Ivan Izmestiev. Gauss images of hyperbolic cusps with convex

More information

The basics of rigidity

The basics of rigidity The basics of rigidity Lectures I and II Session on Granular Matter Institut Henri Poincaré R. Connelly Cornell University Department of Mathematics 1 What determines rigidity? 2 What determines rigidity?

More information

Combinatorial Geometry & Topology arising in Game Theory and Optimization

Combinatorial Geometry & Topology arising in Game Theory and Optimization Combinatorial Geometry & Topology arising in Game Theory and Optimization Jesús A. De Loera University of California, Davis LAST EPISODE... We discuss the content of the course... Convex Sets A set is

More information

POLYTOPES. Grünbaum and Shephard [40] remarked that there were three developments which foreshadowed the modern theory of convex polytopes.

POLYTOPES. Grünbaum and Shephard [40] remarked that there were three developments which foreshadowed the modern theory of convex polytopes. POLYTOPES MARGARET A. READDY 1. Lecture I: Introduction to Polytopes and Face Enumeration Grünbaum and Shephard [40] remarked that there were three developments which foreshadowed the modern theory of

More information

274 Curves on Surfaces, Lecture 5

274 Curves on Surfaces, Lecture 5 274 Curves on Surfaces, Lecture 5 Dylan Thurston Notes by Qiaochu Yuan Fall 2012 5 Ideal polygons Previously we discussed three models of the hyperbolic plane: the Poincaré disk, the upper half-plane,

More information

Lecture 1 Discrete Geometric Structures

Lecture 1 Discrete Geometric Structures Lecture 1 Discrete Geometric Structures Jean-Daniel Boissonnat Winter School on Computational Geometry and Topology University of Nice Sophia Antipolis January 23-27, 2017 Computational Geometry and Topology

More information

Linear Programming in Small Dimensions

Linear Programming in Small Dimensions Linear Programming in Small Dimensions Lekcija 7 sergio.cabello@fmf.uni-lj.si FMF Univerza v Ljubljani Edited from slides by Antoine Vigneron Outline linear programming, motivation and definition one dimensional

More information

Rigid Ball-Polyhedra in Euclidean 3-Space

Rigid Ball-Polyhedra in Euclidean 3-Space Discrete Comput Geom (2013) 49:189 199 DOI 10.1007/s00454-012-9480-y Rigid Ball-Polyhedra in Euclidean 3-Space Károly Bezdek Márton Naszódi Received: 15 September 2011 / Revised: 30 September 2012 / Accepted:

More information

be a polytope. has such a representation iff it contains the origin in its interior. For a generic, sort the inequalities so that

be a polytope. has such a representation iff it contains the origin in its interior. For a generic, sort the inequalities so that ( Shelling (Bruggesser-Mani 1971) and Ranking Let be a polytope. has such a representation iff it contains the origin in its interior. For a generic, sort the inequalities so that. a ranking of vertices

More information

Lecture 2 - Introduction to Polytopes

Lecture 2 - Introduction to Polytopes Lecture 2 - Introduction to Polytopes Optimization and Approximation - ENS M1 Nicolas Bousquet 1 Reminder of Linear Algebra definitions Let x 1,..., x m be points in R n and λ 1,..., λ m be real numbers.

More information

Lecture 5: Properties of convex sets

Lecture 5: Properties of convex sets Lecture 5: Properties of convex sets Rajat Mittal IIT Kanpur This week we will see properties of convex sets. These properties make convex sets special and are the reason why convex optimization problems

More information

GEOMETRIC TOOLS FOR COMPUTER GRAPHICS

GEOMETRIC TOOLS FOR COMPUTER GRAPHICS GEOMETRIC TOOLS FOR COMPUTER GRAPHICS PHILIP J. SCHNEIDER DAVID H. EBERLY MORGAN KAUFMANN PUBLISHERS A N I M P R I N T O F E L S E V I E R S C I E N C E A M S T E R D A M B O S T O N L O N D O N N E W

More information

Computational Geometry

Computational Geometry Computational Geometry 600.658 Convexity A set S is convex if for any two points p, q S the line segment pq S. S p S q Not convex Convex? Convexity A set S is convex if it is the intersection of (possibly

More information

Polar Duality and Farkas Lemma

Polar Duality and Farkas Lemma Lecture 3 Polar Duality and Farkas Lemma October 8th, 2004 Lecturer: Kamal Jain Notes: Daniel Lowd 3.1 Polytope = bounded polyhedron Last lecture, we were attempting to prove the Minkowsky-Weyl Theorem:

More information

Random walks on random planar triangulations via the circle packing theorem

Random walks on random planar triangulations via the circle packing theorem via the circle packing theorem Tel-Aviv University Mini-school on Random Maps and the Gaussian Free Field, ENS Lyon, May 15th 2017 Basic terminology Planar map: a graph embedded in R 2 so that vertices

More information

Course Number: Course Title: Geometry

Course Number: Course Title: Geometry Course Number: 1206310 Course Title: Geometry RELATED GLOSSARY TERM DEFINITIONS (89) Altitude The perpendicular distance from the top of a geometric figure to its opposite side. Angle Two rays or two line

More information

Simplicial Complexes: Second Lecture

Simplicial Complexes: Second Lecture Simplicial Complexes: Second Lecture 4 Nov, 2010 1 Overview Today we have two main goals: Prove that every continuous map between triangulable spaces can be approximated by a simplicial map. To do this,

More information

Tutorial 3 Comparing Biological Shapes Patrice Koehl and Joel Hass

Tutorial 3 Comparing Biological Shapes Patrice Koehl and Joel Hass Tutorial 3 Comparing Biological Shapes Patrice Koehl and Joel Hass University of California, Davis, USA http://www.cs.ucdavis.edu/~koehl/ims2017/ What is a shape? A shape is a 2-manifold with a Riemannian

More information

2. Convex sets. x 1. x 2. affine set: contains the line through any two distinct points in the set

2. Convex sets. x 1. x 2. affine set: contains the line through any two distinct points in the set 2. Convex sets Convex Optimization Boyd & Vandenberghe affine and convex sets some important examples operations that preserve convexity generalized inequalities separating and supporting hyperplanes dual

More information

The Construction of a Hyperbolic 4-Manifold with a Single Cusp, Following Kolpakov and Martelli. Christopher Abram

The Construction of a Hyperbolic 4-Manifold with a Single Cusp, Following Kolpakov and Martelli. Christopher Abram The Construction of a Hyperbolic 4-Manifold with a Single Cusp, Following Kolpakov and Martelli by Christopher Abram A Thesis Presented in Partial Fulfillment of the Requirement for the Degree Master of

More information

ALGORITHMS FOR BALL HULLS AND BALL INTERSECTIONS IN NORMED PLANES

ALGORITHMS FOR BALL HULLS AND BALL INTERSECTIONS IN NORMED PLANES ALGORITHMS FOR BALL HULLS AND BALL INTERSECTIONS IN NORMED PLANES Pedro Martín and Horst Martini Abstract. Extending results of Hershberger and Suri for the Euclidean plane, we show that ball hulls and

More information

Convex Optimization. Convex Sets. ENSAE: Optimisation 1/24

Convex Optimization. Convex Sets. ENSAE: Optimisation 1/24 Convex Optimization Convex Sets ENSAE: Optimisation 1/24 Today affine and convex sets some important examples operations that preserve convexity generalized inequalities separating and supporting hyperplanes

More information

7. The Gauss-Bonnet theorem

7. The Gauss-Bonnet theorem 7. The Gauss-Bonnet theorem 7.1 Hyperbolic polygons In Euclidean geometry, an n-sided polygon is a subset of the Euclidean plane bounded by n straight lines. Thus the edges of a Euclidean polygon are formed

More information

Simplicial Cells in Arrangements of Hyperplanes

Simplicial Cells in Arrangements of Hyperplanes Simplicial Cells in Arrangements of Hyperplanes Christoph Dätwyler 05.01.2013 This paper is a report written due to the authors presentation of a paper written by Shannon [1] in 1977. The presentation

More information

Tangencies between disjoint regions in the plane

Tangencies between disjoint regions in the plane June 16, 20 Problem Definition Two nonoverlapping Jordan regions in the plane are said to touch each other or to be tangent to each other if their boundaries have precisely one point in common and their

More information

Collision Detection. These slides are mainly from Ming Lin s course notes at UNC Chapel Hill

Collision Detection. These slides are mainly from Ming Lin s course notes at UNC Chapel Hill Collision Detection These slides are mainly from Ming Lin s course notes at UNC Chapel Hill http://www.cs.unc.edu/~lin/comp259-s06/ Computer Animation ILE5030 Computer Animation and Special Effects 2 Haptic

More information

Geometric structures on manifolds

Geometric structures on manifolds CHAPTER 3 Geometric structures on manifolds In this chapter, we give our first examples of hyperbolic manifolds, combining ideas from the previous two chapters. 3.1. Geometric structures 3.1.1. Introductory

More information

Convex Sets. CSCI5254: Convex Optimization & Its Applications. subspaces, affine sets, and convex sets. operations that preserve convexity

Convex Sets. CSCI5254: Convex Optimization & Its Applications. subspaces, affine sets, and convex sets. operations that preserve convexity CSCI5254: Convex Optimization & Its Applications Convex Sets subspaces, affine sets, and convex sets operations that preserve convexity generalized inequalities separating and supporting hyperplanes dual

More information

Linear programming and duality theory

Linear programming and duality theory Linear programming and duality theory Complements of Operations Research Giovanni Righini Linear Programming (LP) A linear program is defined by linear constraints, a linear objective function. Its variables

More information

Curvature Berkeley Math Circle January 08, 2013

Curvature Berkeley Math Circle January 08, 2013 Curvature Berkeley Math Circle January 08, 2013 Linda Green linda@marinmathcircle.org Parts of this handout are taken from Geometry and the Imagination by John Conway, Peter Doyle, Jane Gilman, and Bill

More information

Math 311. Polyhedra Name: A Candel CSUN Math

Math 311. Polyhedra Name: A Candel CSUN Math 1. A polygon may be described as a finite region of the plane enclosed by a finite number of segments, arranged in such a way that (a) exactly two segments meets at every vertex, and (b) it is possible

More information

arxiv: v2 [math.mg] 14 Nov 2012

arxiv: v2 [math.mg] 14 Nov 2012 arxiv:1211.2944v2 [math.mg] 14 Nov 2012 On the optimality of the ideal right-angled 24-cell ALEXANDER KOLPAKOV We prove that among four-dimensional ideal right-angled hyperbolic polytopes the 24-cell is

More information

Coxeter Groups and CAT(0) metrics

Coxeter Groups and CAT(0) metrics Peking University June 25, 2008 http://www.math.ohio-state.edu/ mdavis/ The plan: First, explain Gromov s notion of a nonpositively curved metric on a polyhedral complex. Then give a simple combinatorial

More information

CS599: Convex and Combinatorial Optimization Fall 2013 Lecture 4: Convex Sets. Instructor: Shaddin Dughmi

CS599: Convex and Combinatorial Optimization Fall 2013 Lecture 4: Convex Sets. Instructor: Shaddin Dughmi CS599: Convex and Combinatorial Optimization Fall 2013 Lecture 4: Convex Sets Instructor: Shaddin Dughmi Announcements New room: KAP 158 Today: Convex Sets Mostly from Boyd and Vandenberghe. Read all of

More information

A Study of the Rigidity of Regular Polytopes

A Study of the Rigidity of Regular Polytopes A Study of the Rigidity of Regular Polytopes A Thesis Presented in Partial Fulfillment of the Requirements for the Degree Master of Science in the Graduate School of The Ohio State University By Helene

More information

2. Convex sets. affine and convex sets. some important examples. operations that preserve convexity. generalized inequalities

2. Convex sets. affine and convex sets. some important examples. operations that preserve convexity. generalized inequalities 2. Convex sets Convex Optimization Boyd & Vandenberghe affine and convex sets some important examples operations that preserve convexity generalized inequalities separating and supporting hyperplanes dual

More information

Lecture notes for Topology MMA100

Lecture notes for Topology MMA100 Lecture notes for Topology MMA100 J A S, S-11 1 Simplicial Complexes 1.1 Affine independence A collection of points v 0, v 1,..., v n in some Euclidean space R N are affinely independent if the (affine

More information

Question. Why is the third shape not convex?

Question. Why is the third shape not convex? 1. CONVEX POLYGONS Definition. A shape D in the plane is convex if every line drawn between two points in D is entirely inside D. Convex 6 gon Another convex 6 gon Not convex Question. Why is the third

More information

The equal tangents property

The equal tangents property The equal tangents property J. Jerónimo-Castro, G. Ruiz-Hernández and S. Tabachnikov April 29, 2012 Abstract Let M be a C 2 -smooth strictly convex closed surface in R 3 and denote by H the set of points

More information

CLASSIFICATION OF ORDERABLE AND DEFORMABLE COMPACT COXETER POLYHEDRA IN HYPERBOLIC SPACE

CLASSIFICATION OF ORDERABLE AND DEFORMABLE COMPACT COXETER POLYHEDRA IN HYPERBOLIC SPACE CLASSIFICATION OF ORDERABLE AND DEFORMABLE COMPACT COXETER POLYHEDRA IN HYPERBOLIC SPACE DHRUBAJIT CHOUDHURY, SUHYOUNG CHOI, AND GYE-SEON LEE Abstract. The aim of this work is to investigate properties

More information

60 2 Convex sets. {x a T x b} {x ã T x b}

60 2 Convex sets. {x a T x b} {x ã T x b} 60 2 Convex sets Exercises Definition of convexity 21 Let C R n be a convex set, with x 1,, x k C, and let θ 1,, θ k R satisfy θ i 0, θ 1 + + θ k = 1 Show that θ 1x 1 + + θ k x k C (The definition of convexity

More information

Invariant Measures. The Smooth Approach

Invariant Measures. The Smooth Approach Invariant Measures Mathieu Desbrun & Peter Schröder 1 The Smooth Approach On this show lots of derivatives tedious expressions in coordinates For what? only to discover that there are invariant measures

More information

1. CONVEX POLYGONS. Definition. A shape D in the plane is convex if every line drawn between two points in D is entirely inside D.

1. CONVEX POLYGONS. Definition. A shape D in the plane is convex if every line drawn between two points in D is entirely inside D. 1. CONVEX POLYGONS Definition. A shape D in the plane is convex if every line drawn between two points in D is entirely inside D. Convex 6 gon Another convex 6 gon Not convex Question. Why is the third

More information

Simplicial Hyperbolic Surfaces

Simplicial Hyperbolic Surfaces Simplicial Hyperbolic Surfaces Talk by Ken Bromberg August 21, 2007 1-Lipschitz Surfaces- In this lecture we will discuss geometrically meaningful ways of mapping a surface S into a hyperbolic manifold

More information

Other Voronoi/Delaunay Structures

Other Voronoi/Delaunay Structures Other Voronoi/Delaunay Structures Overview Alpha hulls (a subset of Delaunay graph) Extension of Voronoi Diagrams Convex Hull What is it good for? The bounding region of a point set Not so good for describing

More information

Geometric structures on manifolds

Geometric structures on manifolds CHAPTER 3 Geometric structures on manifolds In this chapter, we give our first examples of hyperbolic manifolds, combining ideas from the previous two chapters. 3.1. Geometric structures 3.1.1. Introductory

More information

Polygons and Convexity

Polygons and Convexity Geometry Week 4 Sec 2.5 to ch. 2 test Polygons and Convexity section 2.5 convex set has the property that any two of its points determine a segment contained in the set concave set a set that is not convex

More information

Joint Mathematics Meetings 2014

Joint Mathematics Meetings 2014 Joint Mathematics Meetings 2014 Patterns with Color Symmetry on Triply Periodic Polyhedra Douglas Dunham University of Minnesota Duluth Duluth, Minnesota USA Outline Background Triply periodic polyhedra

More information

On Evasiveness, Kneser Graphs, and Restricted Intersections: Lecture Notes

On Evasiveness, Kneser Graphs, and Restricted Intersections: Lecture Notes Guest Lecturer on Evasiveness topics: Sasha Razborov (U. Chicago) Instructor for the other material: Andrew Drucker Scribe notes: Daniel Freed May 2018 [note: this document aims to be a helpful resource,

More information

Given a graph, find an embedding s.t. greedy routing works

Given a graph, find an embedding s.t. greedy routing works Given a graph, find an embedding s.t. greedy routing works Greedy embedding of a graph 99 Greedy embedding Given a graph G, find an embedding of the vertices in R d, s.t. for each pair of nodes s, t, there

More information

1 Appendix to notes 2, on Hyperbolic geometry:

1 Appendix to notes 2, on Hyperbolic geometry: 1230, notes 3 1 Appendix to notes 2, on Hyperbolic geometry: The axioms of hyperbolic geometry are axioms 1-4 of Euclid, plus an alternative to axiom 5: Axiom 5-h: Given a line l and a point p not on l,

More information

arxiv: v1 [cs.cg] 11 Sep 2007

arxiv: v1 [cs.cg] 11 Sep 2007 Unfolding Restricted Convex Caps Joseph O Rourke arxiv:0709.1647v1 [cs.cg] 11 Sep 2007 September 11, 2007 Abstract This paper details an algorithm for unfolding a class of convex polyhedra, where each

More information

Discrete minimal surfaces of Koebe type

Discrete minimal surfaces of Koebe type Discrete minimal surfaces of Koebe type Alexander I. Bobenko, Ulrike Bücking, Stefan Sechelmann March 5, 2018 1 Introduction Minimal surfaces have been studied for a long time, but still contain unsolved

More information

The radius for a regular polygon is the same as the radius of the circumscribed circle.

The radius for a regular polygon is the same as the radius of the circumscribed circle. Perimeter and Area The perimeter and area of geometric shapes are basic properties that we need to know. The more complex a shape is, the more complex the process can be in finding its perimeter and area.

More information

Algebraic Geometry of Segmentation and Tracking

Algebraic Geometry of Segmentation and Tracking Ma191b Winter 2017 Geometry of Neuroscience Geometry of lines in 3-space and Segmentation and Tracking This lecture is based on the papers: Reference: Marco Pellegrini, Ray shooting and lines in space.

More information

ON THE MAXIMAL VOLUME OF THREE-DIMENSIONAL HYPERBOLIC COMPLETE ORTHOSCHEMES

ON THE MAXIMAL VOLUME OF THREE-DIMENSIONAL HYPERBOLIC COMPLETE ORTHOSCHEMES Proceedings of the Institute of Natural Sciences, Nihon University No.49 04 pp.63 77 ON THE MAXIMAL VOLUME OF THREE-DIMENSIONAL HYPERBOLIC COMPLETE ORTHOSCHEMES Kazuhiro ICHIHARA and Akira USHIJIMA Accepted

More information

Convex Sets (cont.) Convex Functions

Convex Sets (cont.) Convex Functions Convex Sets (cont.) Convex Functions Optimization - 10725 Carlos Guestrin Carnegie Mellon University February 27 th, 2008 1 Definitions of convex sets Convex v. Non-convex sets Line segment definition:

More information

Introduction to geometry

Introduction to geometry 1 2 Manifolds A topological space in which every point has a neighborhood homeomorphic to (topological disc) is called an n-dimensional (or n-) manifold Introduction to geometry The German way 2-manifold

More information

CS522: Advanced Algorithms

CS522: Advanced Algorithms Lecture 1 CS5: Advanced Algorithms October 4, 004 Lecturer: Kamal Jain Notes: Chris Re 1.1 Plan for the week Figure 1.1: Plan for the week The underlined tools, weak duality theorem and complimentary slackness,

More information

DISCRETE DIFFERENTIAL GEOMETRY: AN APPLIED INTRODUCTION Keenan Crane CMU /858B Fall 2017

DISCRETE DIFFERENTIAL GEOMETRY: AN APPLIED INTRODUCTION Keenan Crane CMU /858B Fall 2017 DISCRETE DIFFERENTIAL GEOMETRY: AN APPLIED INTRODUCTION Keenan Crane CMU 15-458/858B Fall 2017 LECTURE 10: DISCRETE CURVATURE DISCRETE DIFFERENTIAL GEOMETRY: AN APPLIED INTRODUCTION Keenan Crane CMU 15-458/858B

More information

Voronoi Diagrams, Delaunay Triangulations and Polytopes

Voronoi Diagrams, Delaunay Triangulations and Polytopes Voronoi Diagrams, Delaunay Triangulations and Polytopes Jean-Daniel Boissonnat MPRI, Lecture 2 Computational Geometry Learning Voronoi, Delaunay & Polytopes MPRI, Lecture 2 1 / 43 Voronoi diagrams in nature

More information

Combinatorial constructions of hyperbolic and Einstein four-manifolds

Combinatorial constructions of hyperbolic and Einstein four-manifolds Combinatorial constructions of hyperbolic and Einstein four-manifolds Bruno Martelli (joint with Alexander Kolpakov) February 28, 2014 Bruno Martelli Constructions of hyperbolic four-manifolds February

More information

WEAKLY INSCRIBED POLYHEDRA

WEAKLY INSCRIBED POLYHEDRA WEAKLY INSCRIBED POLYHEDRA HAO CHEN AND JEAN-MARC SCHLENKER Abstract. We study convex polyhedra in RP 3 with all their vertices on a sphere. In particular, we do not require that the polyhedra lie in the

More information

Lecture 11 Combinatorial Planning: In the Plane

Lecture 11 Combinatorial Planning: In the Plane CS 460/560 Introduction to Computational Robotics Fall 2017, Rutgers University Lecture 11 Combinatorial Planning: In the Plane Instructor: Jingjin Yu Outline Convex shapes, revisited Combinatorial planning

More information

arxiv: v1 [math.co] 12 Aug 2018

arxiv: v1 [math.co] 12 Aug 2018 CONVEX UNION REPRESENTABILITY AND CONVEX CODES R. AMZI JEFFS AND ISABELLA NOVIK arxiv:1808.03992v1 [math.co] 12 Aug 2018 Abstract. We introduce and investigate d-convex union representable complexes: the

More information

6.3 Poincare's Theorem

6.3 Poincare's Theorem Figure 6.5: The second cut. for some g 0. 6.3 Poincare's Theorem Theorem 6.3.1 (Poincare). Let D be a polygon diagram drawn in the hyperbolic plane such that the lengths of its edges and the interior angles

More information

A convexity theorem for real projective structures

A convexity theorem for real projective structures arxiv:0705.3920v1 [math.gt] 27 May 2007 A convexity theorem for real projective structures Jaejeong Lee Abstract Given a finite collection P of convex n-polytopes in RP n (n 2), we consider a real projective

More information

Chapter 8. Voronoi Diagrams. 8.1 Post Oce Problem

Chapter 8. Voronoi Diagrams. 8.1 Post Oce Problem Chapter 8 Voronoi Diagrams 8.1 Post Oce Problem Suppose there are n post oces p 1,... p n in a city. Someone who is located at a position q within the city would like to know which post oce is closest

More information

The Classification Problem for 3-Manifolds

The Classification Problem for 3-Manifolds The Classification Problem for 3-Manifolds Program from ca. 1980: 1. Canonical decomposition into simpler pieces. 2. Explicit classification of special types of pieces. 3. Generic pieces are hyperbolic

More information

Introduction to Rational Billiards II. Talk by John Smillie. August 21, 2007

Introduction to Rational Billiards II. Talk by John Smillie. August 21, 2007 Introduction to Rational Billiards II Talk by John Smillie August 21, 2007 Translation surfaces and their singularities Last time we described the Zemlyakov-Katok construction for billiards on a triangular

More information