This is the English version of the material (lecture notes, exercises) of a mathematical course taught at the University of Osnabrück. So this is not an online-course, only the material for a real university course. The material is organized in a modular way (e.g. facts, proofs, examples, exercises are in separate files) so that it can be used also in other courses. The mathematical material is quite standard for a university beginners class, and the course has been taught several times. The English version is a direct translation. Suggestions are welcome.
