The three Pauli matrices are normally given  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.