These commutation relations mean that L has the mathematical structure of a Lie algebra, and the ε lmn are its structure constants. In this case, the Lie algebra is SU(2) or SO(3) in physics notation ( su ⁡ ⁡ ( 2 ) or so ⁡ ⁡ ( 3 ) respectively in mathematics notation), i.e. Lie algebra associated with rotations in three dimensions. The same is true of J and S. The reason is discussed below. These commutation relations are relevant for measurement and uncertainty, as discussed further below.