SOLUBLE MODEL OF 4-FERMION INTERACTIONS IN DESITTER SPACE

We consider the theory of four-fermion interactions with N-component f ermions in de Sitter space. It is found that the effective potential f or a composite operator in the theory is calculable in the leading ord er of the 1/N expansion for arbitrary space-time dimensions less than four. The resulting effective potential is analyzed by varying both th e four-fermion coupling constant and the curvature of the space-time. The critical curvature at which the dynamically generated fermion mass disappears is found to exist and is calculated analytically. The dyna mical fermion mass is expressed as a function of the space-time curvat ure.