CP invariance in a leptonic sector and mixing the Majorana mass neutrinos

Consideration is being given to neutrino mixing with Majorana masses in assumption that CP invariance in a leptonic sector takes place. It is shown that phases of mixing matrix elements are determined both by CP-parities of Majorana neutrinos and arbitrary sign factors xi sub(H) entering conditions complied by Majorana fields. It is also shown that probabilities of neutrinoless double β-decay depend only on relative CP parities of neutrinos with Majorana masses (and do not depend on xi sub(k)) and CP parities of Majorana neutrino don't enter into expressions for neutrino oscillation