Projective Representations Construction for Different Points of   Brillouin Zone. Application for Space Symmetry Groups $P4_1 2_1 2$ and $P4_3   2_1 2$
  It was suggested method of constructing of irreducible projective representations in different points of Brilluin zone. Points \Gamma, \Lambda, Z, S, A, \Sigma, M, V, R, and X of space symmetry groups $P4_{1}2_{1}2$ and $P4_{3}2_{1}2$ were examined. At each of these points one- and two-valued irreducible projective representations of wave vector groups were constructed for two enantiomorphous modifications. Influence of time inversion at these points also was taken into consideration by means of Herring criterion. 
Victor Gubanov, Sergiy Koryakov