Showing papers on "Pushdown automaton published in 1984"
TL;DR: The classes of languages accepted by alternating pushdown automata, alternating stack Automata, and alternating nonerasing stack automata are characterized in terms of complexity classes defined by time bounded deterministic Turing machines.
Abstract: The classes of languages accepted by alternating pushdown automata, alternating stack automata, and alternating nonerasing stack automata, both with and without an auxiliary space bounded worktape, are characterized in terms of complexity classes defined by time bounded deterministic Turing machines. It is also shown that alternating 2-way finite state machines accept only regular languages.
106 citations
TL;DR: An interactive pushdown automaton is defined as a model for user interface management dialogue control and examples are given for how various features present in otheruser interface management systems are modeled using the IPDA.
Abstract: An interactive pushdown automaton is defined as a model for user interface management dialogue control. The relationships between dialogue control and device handling are defined in terms of acquiring, releasing, enabling, and disabling of devices. Input modes are defined by sets of acquired devices and input states are defined by sets of enabled devices. A specified automaton describes the dialogue. Semantic controls of parse transitions, as well as pervasive transitions for exceptional conditions, are supported in the automaton. Algorithms are given to convert a specified automaton into an executable automaton. For the executable automaton an interpretation algorithm, which incorporates the control of input modes and states, is given. Examples are given for how various features present in other user interface management systems are modeled using the IPDA.
51 citations
TL;DR: It is shown that if a language over a two-letter alphabet belongs to P, then its unary encoding belongs to 2DPDA(1).
16 citations
TL;DR: The result is used to show that the hierarchy of classes of languages accepted by pushdown automata based on the number of alternations collapses at the second level of the hierarchy.
Abstract: Languages accepted by alternating auxiliary pushdown automata using simultaneously a(n) alternations and s(n) space are shown to be members of the class of languages accepted by nondeterministic Turing machines using a(n) 2es(n) space for some c > 0. This result is used to show that the hierarchy of classes of languages accepted by pushdown automata based on the number of alternations collapses at the second level of the hierarchy. The power of alternation bounded pushdown automata without auxiliary storage is also investigated.
15 citations
8 citations
Proceedings Article•
16 Jul 1984
8 citations
TL;DR: The direct branching algorithm of [25] is extended by providing a technique called ‘halting’ for dealing with nodes with unbounded degree in the comparison tree by allowing the algorithm to check equivalence of two deterministic pushdown automata when none of them are real-time, but in a certain condition that properly contains a case where one of them is real- time strict.
7 citations
Journal Article•
6 citations
03 Sep 1984
TL;DR: It is proved that every language accepted by two-way nondeterministic pushdown automaton can be recognized on RAM in O(n3/log n) time.
Abstract: We prove: 1) every language accepted by two-way nondeterministic pushdown automaton can be recognized on RAM in O(n3/log n) time; 2) every language accepted by two-way loop-free pushdown automaton can be recognized in O(n3/log2n) time; 3) every context-free language can be recognized on-line in O(n3/log2n) time. We improve the results of [1,7,4].
4 citations
16 Jul 1984
TL;DR: It is proved that, given the same hypothesis, the largest central language included in an algebraic infinitary language, remains algebraic.
Abstract: We are interested in infinitary languages recognized by a pushdown automaton. We, then, give theorems of characterization of such closed, central, normal or perfect languages (considering a number of hypothesis of continuity in computations of the automaton, for last three classes). Besides, it is proved that, given the same hypothesis, the largest central (respectively normal, perfect, language included in an algebraic infinitary language, remains algebraic.
4 citations
16 Jul 1984
TL;DR: It is shown that the finite minimal stacking and “simple” strict restricted (a subclass of strict restricted) deterministic pushdown automata (FMS-DPDA's SSR-DPda's, respectively) can be simulated by offline Turing machines simultaneously in space S(n) and time n2/S(n).
Abstract: In this paper we present some space/time efficient Turing machine algorithms for recognizing some subclasses of DCFL's. In particular, we show that the finite minimal stacking and “simple” strict restricted (a subclass of strict restricted) deterministic pushdown automata (FMS-DPDA's SSR-DPDA's, respectively) can be simulated by offline Turing machines simultaneously in space S(n) and time n2/S(n) for any tape function S(n) satisfying log n ≤ S(n) ≤ n which is constructable in n2/S(n) time. Related techniques can be used to give interesting characterizations of 2-head 2-way finite automata, both deterministic and nondeterministic. In particular we show that a 2-head 2-way deterministic finite automataton is equivalent to a simple type of 2-way deterministic checking stack automaton. This is in contrast to a result which shows that 2-way nondeterministic checking stack automata are equivalent to nondeterministic linear bounded automata. We also show that a language L is accepted by a 2k-head two-way nondetermistic finite automaton if and only if it is accepted by a k-head two-way nondeterministic pushdown automaton which makes at most one reversal on its stack.
Book•
16 Jul 1984
TL;DR: The theory of data dependencies - An overview of VLSI and its implications for graph grammars.
Abstract: The theory of data dependencies - An overview.- The VLSI revolution in theoretical circles.- Tuple sequences and indexes.- The complexity of cubical graphs.- P-generic sets.- Functional dependencies and disjunctive existence constraints in database relations with null values.- The algebra of recursively defined processes and the algebra of regular processes.- Algebraic specification of exception handling and error recovery by means of declarations and equations.- Building the minimal DFA for the set of all subwords of a word on-line in linear time.- The complexity and decidability of separation.- Concurrent transmissions in broadcast networks.- Linear searching for a square in a word.- Domain algebras.- Principality results about some matrix languages families.- Oriented equational clauses as a programming language.- Relational algebra operations and sizes of relations.- Some results about finite and infinite behaviours of a pushdown automaton.- On the relationship of CCS and petri nets.- Communicating finite state machines with priority channels.- A modal characterization of observational congruence on finite terms of CCS.- Communication complexity.- Space and time efficient simulations and characterizations of some restricted classes of PDAS.- A complete axiom system for algebra of closed-regular expression.- The complexity of finding minimum-length generator sequences.- On probabilistic tape complexity and fast circuits for matrix inversion problems.- On three-element codes.- Recursion depth analysis for special tree traversal algorithms.- Performance analysis of Shamir's attack on the basic Merkle-Hellman knapsack cryptosystem.- Measures of presortedness and optimal sorting algorithms.- Languages and inverse semigroups.- Area-time optimal vlsi integer multiplier with minimum computation time.- On the interpretation of infinite computations in logic programming.- A linear time algorithm to solve the single function coarsest partition problem.- Complexite des facteurs des mots infinis engendres par morphismes iteres.- Automates boustrophedon, semi-groupe de birget et monoide inversif libre.- Probabilistic bidding gives optimal distributed resource allocation.- Partial order semantics versus interleaving semantics for CSP - like languages and its impact on fairness.- Cancellation, pumping and permutation in formal languages.- A hardware implementation of the CSP primitives and its verification.- Factorization of univariate integer polynomials by diophantine approximation and an improved basis reduction algorithm.- Robust algorithms: A different approach to oracles.- Node weighted matching.- The propositional mu-calculus is elementary.- AVL-trees for localized search.- The simple roots of real-time computation hierarchies.- Computational complexity of an optical disk interface.- Encoding graphs by derivations and implications for the theory of graph grammars.- Sampling algorithms for differential batch retrieval problems (extended abstract).
03 Sep 1984
TL;DR: This paper deals with algebraic power series over a commutative semiring A that is algebraic if and only if it is the behavior of a proper pushdown automaton.
Abstract: This paper deals with algebraic power series over a commutative semiringA. A characteristization result states that a power series is algebraic if and only if it is the behavior of a proper pushdown automaton.
TL;DR: Conditions under which the union of a finite number of certain bounded deterministic languages is also deterministic are presented, demonstrating how several deterministic pushdown automata may be merged into one when their conditions are satisfied.
Abstract: This paper presents conditions under which the union of a finite number of certain bounded deterministic languages is also deterministic. The languages under consideration are defined by conditions on the generators of linear sets. Similarly, the conditions given for the union to be deterministic are conditions among generators for several linear sets. We establish the result by demonstrating how several deterministic pushdown automata may be merged into one when our conditions are satisfied.