Relativistic Algebra of Space-Time and Algebrodynamics
  We consider a manifestly Lorentz invariant form $\mathbb L$ of the biquaternion algebra and its generalization to the case of curved manifold. The conditions of $\mathbb L$-differentiability of $\mathbb L$-functions are formulated and considered as the primary equations for fundamental fields modeled with such functions. The exact form of the effective affine connection induced by $\mathbb L$-differentiability equations is obtained for the flat and curved cases. In the flat case, the integrability conditions of the latter lead to the self-duality of the corresponding curvature, thus ensuring that the source-free Maxwell and $SL(2,\mathbb C)$ Yang-Mills equations hold on the solutions of the $\mathbb L$-differentiability equations 
Vladimir V. Kassandrov and Jozeph A. Rizcallah
gr-qc hep-th math-ph math.MP