I have been studying the dynamics of free top from Morin's book. In his book when describing the dynamics,he writes down the equation of motion as shown in screenshot. However,I am not able to understand which term refers to which coordinate system. For eg: Here ##\omega## refers to angular velocity in the frame of centre of mass(body frame) or in fixed frame(space frame)? As Morin tells,the torque on L.H.S are calculated in frame of fixed point or CoM so that torque vanishes. So ##\omega## should be in body frame? In short, can you answer in brief which term in Euler Equation refers to which coordinate?