  The components \(\gamma^{i}_{2}\) and \(\xi^{\alpha}_{2}\) of the  4-acceleration and 3-acceleration can be thought of as the dynamic  descriptors of a material body. On the other hand, the components  \(\Gamma^{i}_{2}(x^{i},\gamma^{i}_{1}\)) and  \(\Pi^{\alpha}_{2}(x^{i}, \xi^{\alpha}_{1}\)) of the  geodesic acceleration field, and the geodesic directing field,  respectively, are field quantities. The differences 