1. The problem statement, all variables and given/known data Good day, From my reading, SU(4) have 15 parameter and SU(2) has 3 paramater that range differently with certain parameter(rotation angle). And all the parameter is linearly independent to each other. My question are: 1. What the characteristic of each of the parameter? 2. If I choose two of them, what is the reason behind the theory? Can anyone explain to me or suggest any book/paper to me to understand the parameter itself.