Quantum \(\mathrm{SO}(3)\) groups and quantum group actions on \(M_{2}\) (Q2269729)

Summary: Answering a question of Shuzhou Wang we give a description of quantum \(\mathrm{SO}(3)\) groups of Podleś as universal compact quantum groups acting on the \(C^*\)-algebra \(M_{2}\) and preserving the Powers state. We use this result to give a complete classification of all continuous compact quantum group actions on \(M_{2}\).