  A five-dimensional seesaw framework is analyzed with the
lepton-number-violating propagator of bulk right-handed neutrinos. That can
bypass summing up the effects of heavy Majorana particles whose masses and
wavefunctions are not exactly known. The propagator method makes it easier to
evaluate the seesaw-induced neutrino mass for various boundary conditions of
bulk neutrinos and in a general background geometry, including the warped extra
dimension. It is also found that the higher-dimensional seesaw gives a natural
framework for the inverse seesaw suppression of low-energy neutrino masses.
