Forming groups with 4 × 4 matrices
J. R. Harris · The Mathematical Gazette · 2010
The three Pauli matrices are normally given [1] as the 2 × 2 matrices:where ‘i’ is the usual complex number imaginary unit.These matrices obey the relations a2 = I = b2 = c2(where I is the 2 × 2 identity matrix), as well as the anticommutation relations:Within the quantities ia,ib and ic,i is a scalar multiplier of the 2 × 2 Pauli matrices and, of course, commutes with each of a, b, c.