where T is just an ordinary matrix. For complex fields, complex conjugation may be required, for which the mapping K : ( x + i y ) ↦ ↦ ( x − − i y ) can be thought of as a 2x2 matrix. For a Dirac spinor, T cannot be written as a 4x4 matrix, because, in fact, complex conjugation is indeed required; however, it can be written as an 8x8 matrix, acting on the 8 real components of a Dirac spinor.