Book:Peter D. Lax/Functional Analysis
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Peter D. Lax: Functional Analysis
Published $\text {2002}$, Wiley
- ISBN 978-0471556046
Subject Matter
Contents
Foreword
- 1. Linear Spaces
- Axioms for linear spaces
- Infinite dimensional examples
- Subspace, linear span
- Quotient space
- Isomorphism
- Convex sets
- Extreme subsets
- 2. Linear Maps
- 2.1 Algebra of linear maps
- Axioms of linear maps
- Sums and composites
- Invertible linear maps
- Nullspace and range
- Invariant subspaces
- 2.2 Index of a linear map
- Degenrate maps
- Pseudoinverse
- Index
- Product formula for the index
- Stability of the index
- 3. The Hahn-Banach Theorem
- 3.1 The extension theorem
- Positive homogeneous, subadditive functionals
- Extension of linear functionals
- Gauge functions of convex sets
- 3.2 Geometric Hahn-Banach theorem
- The hyperplane separation theorem
- 3.3 Extensions of Hahn-Banach theorem
- The Agnew-Morse theorem
- The Bohnenblust-Sobczyk-Soukhomlinov theorem
- 4. Applications of the Hahn-Banach Theorem
- 4.1 Extension of positive linear functionals
- 4.2 Banach limits
- 4.3 Finitely additive invariant set functions
- Historical note
- 5. Normed Linear Spaces
- 5.1 Norms
- Norms for quotient spaces
- Complete normed linear spaces
- The spaces $C$, $B$
- $L^p$ spaces and Hölder's inequality
- Sobolev spaces, embedding theorems
- Separable spaces
- 5.2 Noncompactness of the unit ball
- Uniform convexity
- The Mazur-Ulam theorem on isometries
- 5.3 Isometries
- 6. Hilbert Space
- 6.1 Scalar product
- Schwarz inequality
- Parallelogram identity
- Completeness, closure
- $l^2,L^2$
- 6.2 Closest point in a closed convext subset
- Orthogonal complement of a subspace
- Orthogonal decomposition
- 6.3 Linear functionals
- The Riesz-Frechet representation theorem
- Lax-Milgram lemma
- 6.4 Linear span
- Orthogonal projection
- Orthonormal bases, Gram-Schmidt process
- Isometries of Hilbert space
- 7. Applications of a Hilbert Space Results
- 7.1 Radon-Nikodym theorem
- 7.2 Dirichlet's problem
- Use of the Riesz-Freceht theorem
- Use of the Lax-Milgram theorem
- Use of orthogonal decomposition
- 8. Duals of Normed Linear Spaces
- 8.1 Bounded linear functionals
- Dual space
- 8.2 Extension of bounded linear functionals
- Dual characterization of the norm
- Dual characterization of distance from a subspace
- Dual characterization of the closed linear span of a set
- 8.3 Reflexive spaces
- Reflexivity of $L^p$, $1 < p < \infty$
- Separable spaces
- Separability of the dual
- Dual of $\map C Q$, $Q$ compact
- Reflexivity of subspaces
- 8.4 Support function of a set
- Dual characterization of convex hull
- Dual characterization of distance from closed, convex set
- 9. Applications of Duality
- 9.1 Completeness of weighted powers
- 9.2 The Müntz approxiation theorem
- 9.3 Runge's theorem
- 9.4 Dual variational problems in function theory
- 9.5 Existence of Green's function
- 10. Weak Convergence
- 10.1 Uniform boundedness of weakly converging sequences
- Principle of uniform boundedness
- Weakly sequentially closed convex sets
- 10.2 Weak sequential compactness
- Compactness of unit ball in reflexive space
- 10.3 Weak* convergence
- Helly's theorem
- 11. Applications of Weak Convergence
- 11.1 Approximation of the $\delta$ function by continuous functions
- Toeplitz theorem on summability
- 11.2 Divergence of Fourier series
- 11.3 Approximate quadrature
- 11.4 Weak and strong analyticity of vector-valued functions
- 11.5 Existence of solutions of partial differential equations
- Galerkin's method
- 11.6 The representation of analytics functions with positive real part
- Herglotz-Riesz theorem
- 12. The Weak and Weak* Topologies
- Comparison with sequential topology
- Closed convex sets in the weak topology
- Weak compactness
- Alaoglu's theorem
- 13. Locally Convex Topologies and the Krein-Milman Theorem
- 13.1 Separation of points by linear functionals
- 13.2 The Krein-Milman theorem
- 13.3 The Stone-Weierstrass theorem
- 13.4 Choquet's theorem
- 14. Examples of Convex Sets and Their Extreme Points
- 14.1 Positive functionals
- 14.2 Convex functions
- 14.3 Completely monotone functions
- 14.4 Theorems of Caratheodory and Bochner
- 14.5 A theorem of Krein
- 14.6 Positive Harmonic functions
- 14.7 The Hamburger moment problem
- 14.8 G. Birkhoff's conjecture
- 14.9 De Finetti's theorem
- 14.10 Measure-preserving mappings
- Historical note
- 15. Bounded Linear Maps
- 15.1 Boundedness and continuity
- Norm of a bounded linear map
- Transpose
- 15.2 Strong and weak topologies
- Strong and weak sequential convergence
- 15.3 Principle of uniform boundedness
- 15.4 Composition of bounded maps
- 15.5 The open mapping principle
- Closed graph theorem
- 16. Examples of Bounded Linear Maps
- 16.1 Boundedness of integral operators
- Integral operators of Hilbert-Schmidt type
- Integral operators of Holmgren type
- 16.2 The convexity theorem of Marcel Riesz
- 16.3 Examples of bounded integral operators
- The Fourier transform, Parseval's theorem and Hausdorff-Young inequality
- The Hilbert transform
- The Laplace transform
- The Hilbert-Hankel transform
- 16.4 Solution operators for hyperbolic equations
- 16.5 Solution operator for the heat equation
- 16.6 Singular integral operators, pseudodifferential operators and Fourier integral operators
- Fourier integral operators
- 17. Banach Algebras and their Elementary Spectral Theory
- 17.1 Normed algebras
- Invertible elements
- Resolvent set and spectrum
- Resolvent
- Spectral radius
- 17.2 Functional calculus
- Spectral mapping theorem
- Projections
- 18. Gelfand's Theory of Commutative Banach Algebras
- Homomorphisms into $\C$
- Maximal ideals
- Mazur's lemma
- The spectrum as the range of homomorphisms
- The spectral mapping theorem revisited
- The Gelfand representation
- Gelfand topology
- 19. Applications of Gelfand's Theory of Commutative Banach Algebras
- 19.1 The algebra $\map C S$
- 19.2 Gelfand compactification
- 19.3 Absolutely convergent Fourier series
- 19.4 Analytic functions in the closed unit disk
- Analytic functions in the polydisk
- 19.5 Analytic functions in the open unit disk
- 19.6 Wiener's Tauberian theorem
- 19.7 Commutative $\mathcal B^*$ algebras
- Historical note
- 20. Examples of Operators and Their Spectra
- 20.1 Invertible maps
- Boundary points of the spectrum
- 20.2 Shifts
- 20.3 Volterra integral operators
- 20.4 The Fourier transform
- 21. Compact Maps
- 21.1 Basic properties of compact maps
- Compact maps form a two-sided ideal
- Identity plus compact map has index zero
- 21.2 The spectral theory of compact maps
- The transpose of a compact operator is compact
- The Fredholm alternative
- Historical note
- 22. Examples of Compact Operators
- 22.1 Compactness criteria
- Arela-Ascoli compactness criterium
- Rellich compactness criterium
- 22.2 Integral operators
- Hilbert-Schmidt operators
- 22.3 The inverse of elliptic partial differential operators
- 22.4 Operators defined by parabolic equations
- 22.5 Almost orthogonal bases
- 23. Positive Compact Operators
- 23.1 The spectrum of compact positive operators
- 23.2 Stochastic integral operators
- Invariant probability density
- 23.3 Inverse of a second order elliptic operator
- 24. Fredholm's Theory of Integral Equations
- 24.1 The Fredholm determinant and the Fredholm resolvent
- The spectrum of Fredholm operators
- A trace formula for Fredholm operators
- 24.2 Multiplicative property of the Fredholm determinant
- 24.3 The Gelfand-Levitan-Marchenko equation and Dyson's formula
- 25. Invariant Subspaces
- 25.1 Invariant subspaces of compact maps
- The von Neumann-Aronszajn-Smith theorem
- 25.2 Nested invariant subspaces
- Ringrose's theorem
- Unicelullar operators: the Brodsky-Donoghue theorem
- The Robinson-Bernstein and Lomonosov theorems
- Enflo's example
- 26. Harmonic Analysis on a Halfline
- 26.1 The Phragmén-Lindelöf principle for harmonic functions
- 26.2 An abstract Phragmén-Lindelöf principle
- Interior compactness
- 26.3 Asymptotic expansion
- Solutions of elliptic differential equation in a half-cylinder
- 27. Index Theory
- 27.1 The Noether index
- Pseudoinverse
- Stability of index
- Product formula
- Hörmander's stability theorem
- Historical note
- 27.2 Toeplitz operators
- Index-winding number
- The inversion of Toeplitz operators
- Discontinuous symbols
- Matrix Toeplitz operators
- 27.3 Hankel operators
- 28. Compact Symmetric Operators in Hilbert Space
- Variational principle for eigenvalues
- Completness for eigenfunctions
- The variational principles of Fisher and Courant
- Functional calculus
- Spectral theory of compact normal operators
- Unitary operators
- 29. Examples of Compact Symmetric Operators
- 29.1 Convolution
- 29.2 The inverse of a differential operator
- 29.3 The inverse of partial differential operators
- 30. Trace Class and Trace Formula
- 30.1 Polar decomposition and singular values
- 30.2 Trace class, trace norm, trace
- Matrix trace
- 30.3 The trace formula
- Weyl's inequalities
- Lidskii's theorem
- 30.4 The determinant
- 30.5 Examples and counterexamples of trace class operators
- Mercer's theorem
- The trace of integral operators
- A Volterra integral operator
- The trace of the powers of an operator
- 30.6 The Poisson summation formula
- Convolution of $S^1$ and the convergence of Fourier series
- The Selberg trace formula
- 30.7 How to express the index of an operator as a difference of traces
- 30.8 The Hilbert-Schmidt class
- Relation of Hilbert-Schmidt class and trace class
- 30.9 Determinant and trace for operator in Banach spaces
- 31. Spectral Theory of Symmetric, Normal, and Unitary Operators
- 31.1 The spectrum of symmetric operators
- Reality of spectrum
- Upper and lower bounds for the spectrum
- Spectral radius
- 31.2 Functional calculus for symmetric operators
- The square root of a positive operator
- Polar decomposition of bounded operators
- 31.3 Spectral resolution of symmetric operators
- Projection-valued measures
- 31.4 Absolutely continuous, singular and point spectra
- 31.5 The spectral representation of symmetric operators
- Spectral multiplicity
- Unitary equivalence
- 31.6 Spectral resolution of normal operators
- Functional calculus
- Commutative $B^*$ algebras
- 31.7 Spectral resolution of unitary operators
- Historical note
- 32. Spectral Theory of Self-Adjoint Operators
- The Hellinger-Toeplitz theorem
- Definition of self-adjointness
- Domain
- 32.1 Spectral resolution
- Sharpening of Herglotz's theorem
- Cauchy transform of measures
- The spectrum of self-adjoint operator
- Representation of the resolvent as a Cauchy transform
- Projection-valued measures
- 32.2 Spectral resolution using Cayley transform
- 32.3 A functional calculus for self-adjoint operators
- 33. Examples of Self-Adjoint Operators
- 33.1 The extension of unbounded symmetric operators
- 33.2 Examples of extension of symmetric operators; deficiency indices
- The operator $i \paren{\dfrac d {d x} }$ on $\map {C_0^1} \R$, $\map {C_0^1} {\R_+}$ and $C_0^1 \paren {0, 1}$
- Deficiency indices and von Neumann's theorem
- Symmetric operators in a real Hilbert space
- 33.3 The Friedrichs extension
- Semibounded symmetric operators
- Symmetric ODE
- Symmetric elliptic PDE
- 33.4 The Rellich perturbation theorem
- Self-adjointness of Schrodinger operators with singular potentials
- 33.5 The moment problem
- The Hamburger and Stieltjes moment problems
- Uniqueness, or not, of the moment problem
- Historical note
- 34. Semigroups of Operators
- 34.1 Strongly continuous one-parameter semigroups
- Infinitesimal generator
- Resolvent
- Laplace transform
- 34.2 The generation of semigroups
- The Hille-Yosida theorem
- 34.3 The approximation of semigroups
- The Lax equivalence theorem
- Trotter's product formula
- Strang's product formula
- 34.4 Perturbation of semigroups
- Lumer-Phillip's theorem
- Trotter's perturbation theorem
- 34.5 The spectral theory if semigroups
- Phillip's spectral mapping theorem
- Adjoint semigroups
- Semigroups of eventually compact operators
- 35. Groups of Unitary Operators
- 35.1 Stone's theorem
- Generation of unitary groups
- Positive definiteness and Bochner's theorem
- 35.2 Ergodic theory
- von Neumann's mean ergodic theorem
- 35.3 The Koopman group
- Volume-preserving flows
- Metric transitivity
- Time average
- Space average
- 35.4 The wave equation
- In full space-time
- In the exterior of an obstacle
- 35.5 Translation representation
- Sinai's theorem
- Incoming subspaces
- Solution of wave equation in odd number of space dimensions
- Wave propagation outside an obstacle
- 35.6 The Heisenberg commutation relation
- The uncertainty principle
- Weyl's form of the commutation relation
- von Neumman's theorem on pairs of operators that satisfy the commutation relation
- Historical note
- 36. Examples of Strongly Continuous Semigroups
- 36.1 Semigroups defined by parabolic equations
- 36.2 Semigroups defined by elliptic equations
- 36.3 Exponential decay of semigroups
- 36.4 The Lax-Phillips semigroup
- 36.5 The wave equation in the exterior of an obstacle
- 37. Scattering Theory
- 37.1 Perturbation theory
- 37.2 The wave operators
- 37.3 Existence of the wave operators
- 37.4 The invariance of wave operators
- 37.5 Potential scattering
- 37.6 The scattering operator
- Historical note
- 37.7 The Lax-Phillips scattering theory
- 37.8 The zeros of the scattering matrix
- 37.9 The automorphic wave equation
- Faddeev and Pavlor's theory
- The Riemann hypothesis
- 38. A Theorem of Beurling
- 38.1 The Hardy space
- 38.2 Beurling's theorem
- Inner and outer factors
- Factorization in the algebra of bounded analytic functions
- 38.3 The Titchmarsh convolution theorem
- Historical note
Texts
- A. A Riesz-Kakutani representation theorem
- A.1 Positive linear functionals
- A.2 Volume
- A.3 $L$ as a space of functions
- A.4 Measurable sets and measure
- A.5 The Lebesgue measure and integral
- B. Theory of distributions
- B.1 Definitions and examples
- B.2 Operations on distributions
- B.3 Local properties of distributions
- B.4 Applications to partial differential equations
- B.5 The Fourier transform
- B.6 Applications of the Fourier transform
- B.7 Fourier series
- C. Zorn's Lemma
- Author Index
- Subject Index