We construct a consistent framework for treating single-particle properties
in finite translationally invariant (self-bound) many-body systems. The di
fferences with the standard case of fixed-center systems are discussed. For
some properties which result from the Pauli principle in many-fermion syst
ems, these differences are shown to persist even in the limit of a large nu
mber of particles. [S0556-2813(98)03212-9].