Showing papers in "Journal of Computer and System Sciences in 1979"

TL;DR: An input independent average linear time algorithm for storage and retrieval on keys that makes a random choice of hash function from a suitable class of hash functions.

TL;DR: A formal syntax and semantics for the propositional dynamic logic of regular programs is defined and principal conclusions are that deciding satisfiability of length n formulas requires time d n /log n for some d > 1, and that satisfiability can be decided in nondeterministic time cn for some c.

TL;DR: Three simple efficient algorithms with good probabilistic behaviour are described and an algorithm with a run time of O ( n log n ) which almost certainly finds a perfect matching in a random graph of at least cn log n edges is analyzed.

TL;DR: If the firing of a Transition in a Petri net is considered non instantaneous, it becomes possible to replace a transition in a net B by another net 8’, which allows the description and the analysis of a control structure by stepwise refinements.

TL;DR: A model intended to be useful in deriving realistic complexity bounds for tasks requiring list processing is described, and a class of algorithms which compute unions of disjoint sets on-line are defined, proving that any such algorithm requires nonlinear time in the worst case.

TL;DR: A category of implementations of data type extensions is formulated, and it is shown that such a category has a final object in the category of representations of that type.

TL;DR: Lower bounds on the complexity of a set of searching problems under various restrictions on the nature of the primitive operation used to determine each branch in a search tree are studied in this article.

TL;DR: This paper focuses on the design and analysis of a language for the expression of nondeterministic, concurrent, and communicating programs, and one recent attempt to design such a language was done by Hoare.

TL;DR: It is shown graph isomorphism of regular undirected graphs is complete over isomorphicism of explicitly given structures (say Tarski models from logic) and “certificates” for symmetric cubic graphs are introduced.

TL;DR: The relationship between regular trees, equationally defined trees, and Elgot's iterative algebraic theories is established and regular tree characterizations have implications for decision problems involving flowchart schemes interpreted in iterative theories.

TL;DR: A generalization of the LFP, generalizing the Knaster-Tarski formula lub(F”(O)},,, : lubs are substituted by well-ordered colimits and n is allowed to be an arbitrary ordinal.

TL;DR: The feasibility, advantages and relative efficiency of using this recursive representation of a tree T with M vertices to design algorithms on trees is discussed.

TL;DR: This work gives a necessary and sufficient condition for a commutative language to be erasable, and proves the existence of a minimal language for rational transductions in the family of nonrational commUTative languages.

TL;DR: It is shown that, contrary to the case of systems over fields, it is in general impossible to obtain realizations whose dimension equals the rank of the Hankel matrix.

TL;DR: Four new properties of parallel maps for cellular automata are defined, viz., strong surjectiveness, weak surjection, strong injectiveness, and weak injectiveness that are nonequivalent to previously known properties and bridge the gap between bijectiveness and surjection.

TL;DR: It is shown that the equivalence problem for stack uniform automata and the inclusion problem forstack uniform automaton with empty store acceptance are decidable.

TL;DR: Although it is decidable whether an arbitrary context-free language is included in the language accepted by a superdeterministic pushdown store automaton by final state and empty store, inclusion is undecidable for languages accepted byfinal state or accept mode by superd deterministic push down store automata.

TL;DR: It is shown that every machine in this class of deterministic two-way finite automata augmented by reversal-bounded counters operating on inputs over a one-letter alphabet can effectively be reduced to an equivalent (ordinary) finite automaton.

TL;DR: An algorithm is given which will decide, for two given deterministic finite transducers M, whether the input-output behaviours of M and M ′ are identical.

TL;DR: The decidability of whether or not a grammar is LL -regular for a particular regular partition, which was first stated by Nijholt, and the undecidability are proved.

TL;DR: The effects of nondeterminism and of other logics on the family of languages accepted, comparison with finite automata in terms of number of states and a bound on a decision procedure are presented.

TL;DR: The emptiness and the finiteness problems for M ƒ are algorithmically solvable, whereas many other decision problems about M anches are unsolvable, and the composition does not increase the generative capacity of (context-free), arbitrary or of finite index, matrix grammars.

TL;DR: Church's thesis is extended by showing that every computable function N ∗ → N∗ can be characterized as a stack function.

TL;DR: The time hierarchy for k-tape Turing machines is tightened and infinite hierarchies of languages recognizable by k -tape machines with machines with increasing amount of time on the same amount of space are exhibited.

TL;DR: The idea of differentiating between selecting arguments from a set of arguments at the point of invocation and selecting arguments during the run of the procedure is shown to be independent of the evaluation according to value or name, giving rise to four possible parameter passing methods.

TL;DR: The method is applied to examples dealing with compiler optimizations and in particular to the equivalence demonstration of descriptions by attributes, using Knuth's semantic attributes.

TL;DR: Subclasses of the regular grammars, that generate all regular sets but for which equivalence and containment are provably decidable deterministically in polynomial time, are presented.

TL;DR: S(n)-tape bounded nondeterministic Turing machines can be simulated by S(n) bounded deterministic automata which have an auxiliary pushdown storage of length S2(n).

TL;DR: A p-measure is defined as a measure for which Blum's axioms can be proved in a given axiomatic system and it is shown that the complexity class of a p-function contains only p-functions and that all p- functions form a single complexity class.

TL;DR: An infinite hierarchy of deterministic context free languages is introduced and as a consequence the authors get “relative closure” results for certain subfamilies of the deterministic languages.