  Starting from a NJL-type model with N fermion species fermion and difermion
condensates and their associated phase structures are considered at nonzero
chemical potential $\mu$ and zero temperature in spaces with nontrivial
topology of the form $S^1\otimes S^1\otimes S^1$ and $R^2\otimes S^1$. Special
attention is devoted to the generation of the superconducting phase. In
particular, for the cases of antiperiodic and periodic boundary conditions we
have found that the critical curve of the phase transitions between the chiral
symmetry breaking and superconducting phases as well as the corresponding
condensates and particle densities strongly oscillate vs $\lambda\sim 1/L$,
where $L$ is the length of the circumference $S^1$. Moreover, it is shown that
at some finite values of $L$ the superconducting phase transition is shifted to
smaller values both of $\mu$ and particle density in comparison with the case
of $L=\infty$.
