Subject Domain (in DDC) Computer science, information & general works ♦ Data processing & computer science Abstract Four types of balloon automata (defined by one- or two-way input and deterministic or nondeterministic finite control) and closed classes of balloon automata were previously defined by the authors. A set of closed classes, one for each of the four types, is called a $\textit{family}$ if the classes use their infinite storage in the same way. The recursiveness and solvability of the emptiness problem for closed classes are investigated in the present paper. It is shown that in many cases the solvability of one of these questions for one closed class in a family implies that some other question are solvable for the closed classes of that family. ISSN 00045411 Age Range 18 to 22 years ♦ above 22 year Educational Use Research Education Level UG and PG Learning Resource Type Article Publisher Date 1968-04-01 Publisher Place New York e-ISSN 1557735X Journal Journal of the ACM (JACM) Volume Number 15 Issue Number 2 Page Count 8 Starting Page 317 Ending Page 324