  Lorentz's group represented by the hypercomplex system of numbers, which is based on dirac matrices, is investigated. This representation is similar to the space rotation representation by quaternions. This representation has several advantages. Firstly, this is reducible representation. That is why transformation of different geometrical objects (vectors, antisymmetric tensors of the second order and bispinors) are implemented by the same operators. Secondly, the rule of composition of two arbitrary Lorentz's transformations has a simple form. These advantages strongly simplify finding a lot of the laws related to the Lorentz's group. In particular they simplify investigation of the spin connection with Pauli-Lubanski pseudovector and Wigner little group. 
Hypercomplex representation of the Lorentz's group