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Mathematics
Functional Analysis
1. Preliminaries and Foundational Concepts
2. Normed Vector Spaces
3. Banach Spaces
4. Hilbert Spaces
5. Linear Operators on Normed Spaces
6. Fundamental Theorems of Functional Analysis
7. Duality Theory
8. Spectral Theory
9. Advanced Topics
Hilbert Spaces
Inner Product Spaces
Definition of Inner Product
Inner Product Axioms
Examples of Inner Products
Induced Norm
Parallelogram Law
Polarization Identity
Cauchy-Schwarz Inequality
Statement and Proof
Equality Conditions
Hilbert Spaces
Definition as Complete Inner Product Space
Examples of Hilbert Spaces
ℓ² Space
L² Spaces
Sobolev Spaces H¹
Orthogonality
Orthogonal Vectors
Orthogonal Sets
Orthogonal Complements
Properties of Orthogonal Complements
Projection onto Orthogonal Complement
Pythagorean Theorem
Projection Theorem
Best Approximation Problem
Orthogonal Projection
Projection onto Closed Subspaces
Characterization of Projections
Orthonormal Systems
Orthonormal Sets
Orthonormal Bases
Gram-Schmidt Process
Bessel's Inequality
Parseval's Identity
Fourier Series in Hilbert Spaces
Separable Hilbert Spaces
Characterization of Separability
Isomorphism with ℓ²
Riesz Representation Theorem
Statement for Hilbert Spaces
Proof and Applications
Identification of H with H*
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3. Banach Spaces
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5. Linear Operators on Normed Spaces