Fundamental solutions of the Dirac operator in the Friedmann-Lema\^itre-Robertson-Walker spacetime

The equation of the spin-$\frac{1}{2}$ particles in the Friedmann-Lema^itre-Robertson-Walker spacetime is investigated. The retarded and advanced fundamental solutions to the Dirac operator and generalized Dirac operator as well as the fundamental solutions to the Cauchy problem are written in explicit form via the fundamental solution of the wave equation in the Minkowski spacetime.