Topics

Metric and normed spaces

  • Metric spaces
  • Limits
  • Open and closed sets
  • Examples of metric and normed spaces: \(\mathbb{R}^n\); sequence spaces \(\ell_1\), \(\ell_2\) and bounded sequences; function space \(C(\mathbb{R})\) with different norms
  • Bolzano-Weierstrass theorem
  • Cauchy sequences, completeness

Relevant exam problems: 2003-1, 2005-1, 2007-6, 2012-6, 2013-3

Banach fixed point theorem and its applications

  • Contractions in metric spaces
  • Banach fixed point theorem in a complete metric space
  • Proof of the fixed point theorem, iterations
  • Applications to functional equations, linear algebra, integral equations
  • Lipschitz functions in metric spaces
  • Picard-Lindelöf theorem for initial value problem for ODE
  • Picard iterations

Relevant exam problems: 2004-2, 2005-4, 2006-1, 2010-2

Vectors spaces, normed spaces

  • Vector spaces and subspaces
  • Finite basis and dimension
  • Norm, examples
  • Equivalent norms, all norms in a finite dimensional space are equivalent
  • Banach spaces

Relevant exam problems: 2004-7, 2012-4, 2005-3a,b

Inner-product spaces

  • Inner-product spaces
  • Cauchy-Schwarz inequality
  • Parallelogram law
  • Pythagoras theorem and its generalization
  • The closest point theorem
  • Orthogonal projection
  • Fourier coefficients
  • Hilbert spaces
  • Bessels's inequality
  • Orthogonal bases and Parseval's identity
  • Gram-Schmidt orthogonalization

Relevant exam problems: 2004-5, 2006-4, 2013-5a

Linear transformations: finite dimensional spaces

  • Linear transformations and matrices
  • Compositions of linear transformations
  • Change-of-basis matrix and similar matrices
  • Rank of a linear transformation
  • Nullity-rank theorem
  • Eigenvalues, eigenspaces and generalized eigenspaces
  • Caley-Hamilton theorem

Relevant exam problems: 2011-3,

Matrix decompositions

  • QR-decomposition
  • Jordan normal form and its application to linear systems of ODE
  • SVD-decomposition and pseudoinverse

Old exam problems for this section: 2003-3, 2004-3, 2005-2, 2006-2

Linear transformations: vector and normed spaces

  • The vector space \(L(X,Y)\)
  • Kernels and ranges of linear transformations
  • Bounded linear transformations between normed spaces
  • Norm of a linear transformation
  • The space \(B(X,Y)\)
  • Limits of operators
  • Power series of operators
  • \((I-T)^{-1}\)
  • Exponential of an operator

Relevant exam problems: 2005-3c, 2013K-5,

Linear transformations: Hilbert spaces

  • Riesz representation theorem
  • Adjoint operators
  • Self-adjoint and normal operators
  • Unitary operators
  • Spectral theorem for self-adjoint operators (in finite dimensions)
  • Positive definite operators

Relevant exam problems: 2003-4, 2007-5, 2008-5a,b, 2010-5, 2012-5

2015-12-08, Franz Luef