We plan to work on several explicit problems about K-stability of smooth and singular Fano threefolds described in the proposal together with Hamid Abban (Nottingham, England) and Kento Fujita (Osaka, Japan). Hamid Abban works on K-stability of Fano varieites, and birational geometry of Fano varieties. His recent results on K-stability crucially changed the subject over the last two years. Kento Fujita is an expert in the general theory of K-stability of Fano varieties. One of the most important works of Fujita consisted on finding and proving a valuative criterion for K-stability.