  (Weyl (1929c)) notes that the spinor representation of the orthogonal group \(O(1, 3)\) cannot be extended to a representation of the  general linear group \(GL(n)\), \(n = 4\), with the  consequence that it is necessary to employ the Vierbein,  tetrad or Lorentz-structure formulation of the theory of  general relativity in order to incorporate Dirac’s spinor fields  \(\psi(x)\): 