This project by Tomas Michalik shows great originality, independence, and
mathematical maturity in his research. The author's understanding of group
theory, general relativity, differential geometry, and variational calculus is
exceptional. The thesis more than fulfills the goal of the project.

The bachelor thesis deals with the de Sitter model universe. Although being purely classical, this model has an actual meaning in quantum gravity-inspired considerations of modified special relativity. In the first part the de Sitter model is introduced by geometrical and group-theoretical methods, in the second and third part the dynamics of massive particles and photons is studied with the result that the speed of light decreases globally with time. The most important part is the discovery and correction of a mistake in ref. [5], which invalidates some conclusions in that paper. Altogether the thesis is original, actual, and well-founded. Otázky k obhajobě:

1. In eq. 1.32 there is a typographic error, c on the right-hand side should be “c slash”.
2. The text is rather brief and at some places more explanation would be helpful, for example in chapter 2.2, where variations are considered. How is the difference of vectors or tensors at different points defined? In the ambient Minkowski space the operator P (below eq. (1.67)) is a partial derivative, does it mean the same in de Sitter space, eq. (1.68) ?