Lying and manipulation in voting procedures

This thesis focuses on the phenomenon of strategic manipulation in collective decision making, i.e. situations where it is beneficial for certain members of the group to derive from their sincere preferences in the voting process. This manipulation complicates the process of collective decision making, leading to situations where lying becomes a successful strategy that some mambers of the group can use to gain an advantage over others. In the thesis, examples of strategic manipulation and a summary of up to date research in the field of social choice theory are included. The main objective is to create a simulation model that can be used to quantify the probability of a successful manipulation. A Monte Carlo simulation using this model is performed on ten voting procedures. Analysed procedures include the most common and intuitive ones, more sophisticated systems created by experts of social choice theory and the most modern attempts to improve democracy by Karel Janeček.