Personal

In the submenu items you will find information on various personal activities.

Chess

When he was young Christian Bär played activley chess in the Schachklub Kaiserslautern 1905. Later chess turned out not to be a good counterbalance to professional mathematics. Thus chess was soon limited to an occasional bughouse chess game. In 2010 the opportunity arose to participate in a simultaneous game against the then chess world champion Viswanathan Anand. After 33 moves however, Christian Bär had to resign.

Photography

The pictures in the galleries have been taken by Christian Bär or Gabriele Kapfer at various occasions. Before 2016, mostly a compact camera Lumix DMC-TZ5 was used and afterwards a system camera Lumix G7. Occasionally, you may find a picture taken on a smartphone. All rights reserved by Christian Bär or Gabriele Kapfer, respectively.

Interactive Exercises

These interactive pages allow you to practice certain mathematical techniques (e.g. calculus of fractions). Javascript needs to be activated in your browser; usually this is the default setup. You can use these pages from mobile devices. So start practicing!

• Union, intersection, set differences
• Power sets
• Injective, surjective and bijective
• Fractions
• Zeros of quadratic polynomials
• Division of polynomials
• Complex numbers
• Finite fields
• Products of vectors
• Matrix multiplication
• Inverting matrices
• Basis transformation
• Matrices representing linear maps
  
• Determinants
• Orientations
• Volume of a parallelotope
• Characteristic polynomials
• Minimal polynomial
• Eigenvalues
• Diagonalizing matrices
• Jordan normal form
• Sylvester's theorem
• Gram-Schmidt process
• Euclidean triangles
• Spherical triangles
• Hyperbolic triangles

These pages use the open source computer algebra system SageMath. The computations are performed on the Sage Cell Server.