In the following year Undecidability and recursive inseparability appeared which proves two results on undecidability in arithmetic, one of which had been suggested by Bernays .
Sa mga sumusunod na taon Undecidability at recursive kawalan ng kayang paghiwalayin lumitaw na proves dalawang mga resulta sa undecidability sa arithmetic, isa sa kung saan nagkaroon na iminungkahi ng Bernays.