title: Some decision problems for bottom-up triangle acceptors.
abstract: It is proved that the emptiness problem for deterministic bottom-up triangle acceptors (BTA's) over a single input symbol is recursively unsolvable. From this result, it is also shown that certain decision problems involving BTA's and BPA's (deterministic bottom-up pyramid acceptors) are unsolvable.
authors.affiliation: Department of Applied Mathematics, Hiroshima University, Hiroshima, Japan; Computer Science Center, University of Maryland, College Park, MD 20742.
authors.forename: A
authors.initials: A
authors.lastname: Nakamura