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Energy of Knots and Conformal Geometry.
Title:
Energy of Knots and Conformal Geometry.
Author:
O'Hara, Jun.
ISBN:
9789812795304
Personal Author:
Physical Description:
1 online resource (306 pages)
Series:
Series on Knots and Everything ; v.33

Series on Knots and Everything
Contents:
Contents -- Preface -- Part 1 In search of the "optimal embedding" of a knot -- Chapter 1 Introduction -- 1.1 Motivational problem -- 1.2 Notations and remarks -- Chapter 2 a-energy functional E(a) -- 2.1 Renormalizations of electrostatic energy of charged knots -- 2.2 Renormalizations of r-a-modified electrostatic energy Ea -- 2.3 Asymptotic behavior of r-a energy of polygonal knots -- 2.4 The self-repulsiveness of E( a ) -- Chapter 3 On E(2) -- 3.1 Continuity -- 3.2 Behavior of E(2) under "pull-tight" -- 3.3 Mobius invariance -- 3.4 The cosine formula for E(2) -- 3.5 Existence of E(2) minimizers -- 3.6 Average crossing number and finiteness of knot types -- 3.7 Gradient regularity of E(2) minimizers and criterion of criticality -- 3.8 Unstable E(2)-critical torus knots -- 3.9 Energy associated to a diagram -- 3.9.1 General framework -- 3.9.2 "X-energy" -- 3.10 Normal projection energies -- 3.11 Generalization to higher dimensions -- Chapter 4 Lp norm energy with higher index -- 4.1 Definition of (a p)-energy functional for knots eap -- 4.2 Control of knots by Eap (eap) -- 4.3 Complete system of admissible solid tori and finiteness of knot types -- 4.4 Existence of Eap minimizers -- 4.5 The circles minimize Eap -- 4.6 Definition of a-energy polynomial for knots -- 4.7 Brylinski's beta function for knots -- 4.8 Other Lp-norm energies -- Chapter 5 Numerical experiments -- 5.1 Numerical experiments on E(2) -- 5.2 a > 2 cases. The limit as n -> oo when a >= 3 -- 5.3 Table of approximate minimum energies -- Chapter 6 Stereo pictures of E(2) minimizers -- Chapter 7 Energy of knots in a Riemannian manifold -- 7.1 Definition of the unit density (a p)-energy EapM -- 7.2 Control of knots by EapM -- 7.3 Existence of energy minimizers -- 7.4 Examples : Energy of knots in S3 and H3 -- 7.4.1 Energy of circles in S3.

7.4.2 Energy of trefoils on Clifford tori in S3 -- 7.4.3 Existence of E(2)S(3) minimizers -- 7.4.4 Energy of knots in H3 -- 7.5 Other definitions -- 7.6 The existence of energy minimizers -- Chapter 8 Physical knot energies -- 8.1 Thickness and ropelength -- 8.2 Four thirds law -- 8.3 Osculating circles and osculating spheres -- 8.4 Global radius of curvature -- 8.5 Self distance type energies denned via the distance function -- 8.6 Relation between these geometric quantities and eap -- 8.7 Numerical computations and applications -- Part 2 Energy of knots from a conformal geometric viewpoint -- Chapter 9 Preparation from conformal geometry -- 9.1 The Lorentzian metric on Minkowski space -- 9.2 The Lorentzian exterior product -- 9.3 The space of spheres -- 9.4 The 4-tuple map and the cross ratio of 4 points -- 9.5 Pencils of spheres -- 9.6 Modulus of an annulus -- 9.7 Cross-separating annuli and the modulus of four points -- 9.8 The measure on the space of spheres A -- 9.9 Orientations of 2-spheres -- Chapter 10 The space of non-trivial spheres of a knot -- 10.1 Non-trivial spheres of a knot -- 10.2 The 4-tuple map for a knot -- 10.3 Generalization of the 4-tuple map to the diagonal -- 10.3.1 Twice tangent spheres -- 10.3.2 Tangent spheres -- 10.3.3 Osculating spheres -- 10.4 Lower semi-continuity of the radii of non-trivial spheres -- Chapter 11 The infinitesimal cross ratio -- 11.1 The infinitesimal cross ratio of the complex plane -- 11.2 The real part as the canonical symplectic form of T*S2 -- 11.3 The infinitesimal cross ratio for a knot -- 11.4 From the cosine formula to the original definition of E(2) -- 11.5 Eo(2)-energy for links -- Chapter 12 The conformal sin energy Esin0 -- 12.1 The projection of the inverted open knot -- 12.2 The geometric meaning of Esin0 -- 12.3 Self-repulsiveness of Esin0.

12.4 Esin0 and the average crossing number -- 12.5 Esin0 for links -- Chapter 13 Measure of non-trivial spheres -- 13.1 Non-trivial spheres tangent spheres and twice tangent spheres -- 13.2 The volume of the set of the non-trivial spheres -- 13.3 The measure of non-trivial spheres in terms of the infinitesimalcross ratio -- 13.4 Non-trivial annuli and the modulus of a knot -- 13.5 Self-repulsiveness of the measure of non-trivial spheres -- 13.6 The measure of non-trivial spheres for non-trivial knots -- 13.7 Measure of non-trivial spheres for links -- Appendix A Generalization of the Gauss formula for the linking number -- A.l The Gauss formula for the linking number -- A.2 The writhe and the self-linking number -- A.3 The total twist -- A.4 Average crossing number -- A.5 The conformal angle and the Gauss integral -- A.6 Mobius invariance of the writhe -- A.7 The circular Gauss map and the inverted open knots -- Appendix B The 3-tuple map to the set of circles in S3 -- B.l The set of unoriented circles in S3 -- B.2 The 3-tuple map to the set of circles -- Appendix C Conformal moduli of a solid torus -- C.l Modulus of a 2-dimensional annulus revisited -- C.2 Conformal moduli of a solid torus -- Appendix D Kirchhoff elastica -- Appendix E Open problems and dreams -- Bibliography -- Index.
Abstract:
Energy of knots is a theory that was introduced to create a "canonical configuration" of a knot - a beautiful knot which represents its knot type. This book introduces several kinds of energies, and studies the problem of whether or not there is a "canonical configuration" of a knot in each knot type. It also considers this problems in the context of conformal geometry. The energies presented in the book are defined geometrically. They measure the complexity of embeddings and have applications to physical knotting and unknotting through numerical experiments. Contents: In Search of the "Optimal Embedding" of a Knot: α-Energy Functional E (α); On E (2); L p Norm Energy with Higher Index; Numerical Experiments; Stereo Pictures of E (2) Minimizers; Energy of Knots in a Riemannian Manifold; Physical Knot Energies; Energy of Knots from a Conformal Geometric Viewpoint: Preparation from Conformal Geometry; The Space of Non-Trivial Spheres of a Knot; The Infinitesimal Cross Ratio; The Conformal Sin Energy E sin θ Measure of Non-Trivial Spheres; Appendices: Generalization of the Gauss Formula for the Linking Number; The 3-Tuple Map to the Set of Circles in S 3; Conformal Moduli of a Solid Torus; Kirchhoff Elastica; Open Problems and Dreams. Readership: Graduate students and researchers in geometry & topology and numerical & computational mathematics.
Local Note:
Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, 2017. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries.
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