Higher derivative four - fermion model in curved spacetime

We discuss the phase structure of a higher derivative four-fermion model in four dimensions in curved spacetime in frames of the 1 Nc-expansion. First, we evaluate in our model the effective potential of two composite scalars in the linear curvature approximation using a local momentum representation in curved spacetime for the higher-derivative propaga-tor which naturally appears. The symmetry breaking phenomenon and phase transition induced by curvature are numerically investigated. A numerical study of the dynamically generated fermionic mass, which depends on the coupling constants and on the cuvature, is also presented.