Orthogonal
Polynomials on the Unit Circle
Table of Contents |
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Part 1: Classical Theory | ||||
Preface to Part 1 | xi | |||
Notation | xvii | |||
Chapter 1: The Basics |
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1.1 | Introduction | 1 | ||
1.2 | Orthogonal Polynomials on the Real Line | 11 | ||
1.3 | Caratheodory and Schur Functions | 25 | ||
1.4 | An Introduction to Operator and Spectral Theory | 40 | ||
1.5 | Verblunsky Coefficients and the Szego Recurrence | 55 | ||
1.6 | Examples of OPUC | 71 | ||
1.7 | Zeros and the First Proof of Verblunsky's Theorem | 90 | ||
Chapter 2: Szego's Theorem | ||||
2.1 | Toeplitz Determinants and Verblunsky Coefficients | 109 | ||
2.2 | Extremal
Properties, the Christoffel Functions, and the Christoffel-Darboux Formula |
117 |
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2.3 | Entropy Semicontinuity and the First Proof of Szego’s Theorem | 136 | ||
2.4 | The Szego Function | 143 | ||
2.5 | Szego's Theorem Using the Poisson Kernel | 151 | ||
2.6 | Khrushchev’s Proof of Szego’s Theorem | 156 | ||
2.7 | Consequences of Szego’s Theorem | 159 | ||
2.8 | A Higher-Order Szego Theorem | 172 | ||
2.9 | The Relative Szego Function | 178 | ||
2.10 | Totik’s Workshop | 184 | ||
2.11 | Riesz Products and Khrushchev’s Workshop | 189 | ||
2.12 | The Workshop of Denisov and Kupin | 197 | ||
2.13 | Matrix-Valued Measures | 206 | ||
Chapter 3: Tools for Geronimus' Theorem | ||||
3.1 | Verblunsky’s Viewpoint: Proofs of Verblunsky’s and Geronimus’ Theorems | 217 | ||
3.2 | Second Kind Polynomials | 222 | ||
3.3 | KW Pairs | 239 | ||
3.4 | Coefficient Stripping and Associated Polynomials | 245 | ||
Chapter 4: Matrix Representations | ||||
4.1 | The GGT Representation | 251 | ||
4.2 | The CMV Representation | 262 | ||
4.3 | Spectral Consequences of the CMV Representation | 274 | ||
4.4 | The Resolvent of the CMV Matrix | 287 | ||
4.5 | Rank Two Perturbations and Decoupling of CMV Matrices | 293 | ||
Chapter 5: Baxter's Theorem | ||||
5.1 | Wiener-Hopf Factorization and the Inverses of Finite Toeplitz Matrices | 301 | ||
5.2 | Baxter's Proof | 313 | ||
Chapter 6: The Strong Szego Theorem | ||||
6.1 | The Ibragimov and Golinskii-Ibragimov Theorems | 319 | ||
6.2 | The Borodin-Okounkov Formula | 333 | ||
6.3 | Representations of U(n) and the Bump-Diaconis Proof | 346 | ||
6.4 | Toeplitz
Determinants as the Statistical Mechanics of Coulomb Gases and Johansson’s Proof |
352 |
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6.5 | The Combinatorial Approach and Kac’s Proof | 368 | ||
6.5 | A Second Look at Ibragimov’s Theorem | 376 | ||
Chapter 7: Verblunsky Coefficients With Rapid Decay | ||||
7.1 | The Rate of Exponential Decay and a Theorem of Nevai-Totik | 381 | ||
7.2 | Detailed Asymptotics of the Verblunsky Coefficients | 387 | ||
Chapter 8: The Density of Zeros | ||||
8.1 | The Density of Zeros Measure via Potential Theory | 391 | ||
8.2 | The Density of Zeros Measure via the CMV Matrix | 403 | ||
8.3 | Rotation Numbers | 410 | ||
8.4 | A Gallery of Zeros | 412 | ||
Bibliography | 425 | |||
Author Index | 457 | |||
Subject Index | 463 | |||
Part 2: Spectral Theory | ||||
xi | ||||
Preface to Part 2 | xiii | |||
Notation | ||||
Chapter 9: Rakhmanov’s Theorem and Related Issues | ||||
9.1 | Rakhmanov’s Theorem via Polynomial Ratios | 467 | ||
9.2 | Khrushchev’s Proof of Rakhmanov’s Theorem | 475 | ||
9.3 | Further Aspects of Khrushchev’s Theory | 485 | ||
9.4 | Introduction to MNT Theory | 493 | ||
9.5 | Ratio Asymptotics | 503 | ||
9.6 | Poincare’s Theorem and Ratio Asymptotics | 512 | ||
9.7 | Weak Asymptotic Measures | 521 | ||
9.8 | Ratio Asymptotics for Varying Measures | 530 | ||
9.9 | Rakhmanov’s Theorem on an Arc | 535 | ||
9.10 | Weak Limits and Relative Szego Asymptotics | 538 | ||
Chapter 10: Techniques of Spectral Analysis | ||||
10.1 | Aronszajn-Donoghue Theory | 545 | ||
10.2 | Spectral Averaging and the Simon-Wolff Criterion | 551 | ||
10.3 | The Gordon-del Rio-Makarov-Simon Theorem | 558 | ||
10.4 | The Group U(1;1) | 564 | ||
10.5 | Lyapunov Exponents and the Growth of Norms in U(1;1) | 581 | ||
10.5A | Appendix: Subshifts | 600 | ||
10.6 | Furstenberg’s Theorem and Random Matrix Products From U(1;1) | 606 | ||
10.7 | The Transfer Matrix Approach to L1 Verblunsky Coefficients | 617 | ||
10.8 | The Jitomirskaya-Last Inequalities | 631 | ||
10.9 | Criteria for A.C. Spectrum | 639 | ||
10.10 | Dependence on the Tail | 648 | ||
10.11 | Kotani Theory | 652 | ||
10.12 | Prufer Variables | 664 | ||
10.13 | Modifying the Measure: Inserting Eigenvalues and Rational Function Multiplication | 673 | ||
10.14 | Decay of CMV Resolvents and Eigenfunctions | 685 | ||
10.15 | Counting Eigenvalues in Gaps: The Birman-Schwinger Principle | 690 | ||
10.16 | Stochastic Verblunsky Coefficients | 701 | ||
Chapter 11: Periodic Verblunsky Coefficients | ||||
11.1 | The Discriminant | 710 | ||
11.2 | Floquet Theory | 719 | ||
11.3 | Calculation of the Weight | 724 | ||
11.4 | An Overview of the Inverse Spectral Problem | 730 | ||
11.5 | The Orthogonal Polynomials Associated to Dirichlet Data | 742 | ||
11.6 | Wall Polynomials and the Determination of Discriminants | 748 | ||
11.7 | Abel’s Theorem and the Inverse Spectral Problem | 753 | ||
11.8 | Almost Periodic Isospectral Tori | 783 | ||
11.9 | Quadratic Irrationalities | 788 | ||
11.10 | Independence of Spectral Invariants and Isospectral Tori | 799 | ||
11.11 | Isospectral Flows | 801 | ||
11.12 | Bounds on the Green’s Function | 808 | ||
11.13 | Genericity Results | 811 | ||
11.14 | Consequences of Many Closed Gaps | 812 | ||
Chapter 12: Spectral Analysis of Specific Classes of Verblunsky Coefficients | ||||
12.1 | Perturbations of Bounded Variation | 817 | ||
12.2 | Perturbations of Periodic Verblunsky Coefficients | 826 | ||
12.3 | Naboko’s Workshop: Dense Point Spectrum in the Szego Class | 829 | ||
12.4 | Generic Singular Continuous Spectrum | 834 | ||
12.5 | Sparse Verblunsky Coefficients | 838 | ||
12.6 | Random Verblunsky Coefficients | 845 | ||
12.7 | Decaying Random Verblunsky Coefficients | 847 | ||
12.8 | Subshifts | 855 | ||
12.9 | High Barriers | 863 | ||
Chapter 13: The Connection to Jacobi Matrices | ||||
13.1 | The Szego Mapping and Geronimus Relations | 871 | ||
13.2 | CMV Matrices and the Geronimus Relations | 881 | ||
13.3 | Szego’s Theorem for OPRL: A First Look | 889 | ||
13.4 | The Denisov-Rakhmanov Theorem | 892 | ||
13.5 | The Damanik-Killip Theorem | 896 | ||
13.6 | The Geronimo-Case Equations | 903 | ||
13.7 | Jacobi Matrices With Exponentially Decaying Coefficients | 912 | ||
13.8 | The P2 Sum Rule and Applications | 920 | ||
13.9 | Szego’s Theorem for OPRL: A Third Look | 937 | ||
Appendix A - Reader's Guide: Topics and Formulae | ||||
A.1 |
What's Done Where | |||
A | Schur functions | 945 | ||
B | Toeplitz matrices and determinants | 945 | ||
C | Szego’s theorem | 946 | ||
D | Aleksandrov families | 946 | ||
E | Zeros of OPUC | 946 | ||
F | Density of zeros | 946 | ||
G | CMV matrices | 947 | ||
H | Periodic Verblunsky coefficients | 947 | ||
I | Stochastic Verblunsky coefficients | 947 | ||
J | Transfer matrices | 948 | ||
K | Asymptotics of orthogonal polynomials | 948 | ||
A.2 |
Formulae | |||
A | Basic objects | 948 | ||
B | Recursion | 950 | ||
C | Bernstein-Szego approximation | 955 | ||
D | Additional OP formulae | 956 | ||
E | Additional Wall polynomial formulae | 956 | ||
F | Matrix representations | 956 | ||
G | Aleksandrov families | 959 | ||
H | Rotation of measure | 960 | ||
I | Sieved polynomials | 960 | ||
J | Toeplitz determinants (see also K) | 961 | ||
K | Szego’s theory | 961 | ||
L | Additional transfer matrix formulae | 964 | ||
M | Periodic Verblunsky coefficients | 966 | ||
N | Connection to Jacobi matrices | 967 | ||
Appendix B - Perspectives | ||||
B.1 | OPRL vs. OPUC | 971 | ||
B.2 | OPUC Analogs of the m-function | 973 | ||
Appendix C - Twelve Great Papers | 975 | |||
Appendix D - Conjectures and Open Questions | ||||
D.1 | Related to Extending Szego’s Theorem | 981 | ||
D.2 | Related to Periodic Verblunsky Coefficients | 981 | ||
D.3 | Spectral Theory Conjectures | 982 | ||
Bibliiography | 983 | |||
Author Index | 1031 | |||
Subject Index | 1039 | |||
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