International Journal of Foundations of Computer Science (INT J FOUND COMPUT S)
The International Journal of Foundations of Computer Science publishes articles which contribute new theoretical results in all areas of the foundations of computer science. The theoretical and mathematical aspects covered include: Algebraic theory of computing and formal systems, Analysis and design of algorithms, Automata and formal languages, Categories in computer science, Combinatorics, Complexity theory, Computational biology and DNA computing, Computer theorem proving, Concurrency, Constructive logic, Crytography, Database theory, Logic and semantics of programs, Logic in artificial intelligence, Logic programming, Models of computation, Program verification and synthesis, Proof and specification in computer science, Quantum computing, Theories and models of internet computing, Theory of learning and inductive inference, Theory of parallel and distributed computing, and Type theory.
Current impact factor: 0.30
Impact Factor Rankings
|2016 Impact Factor||Available summer 2017|
|2014 / 2015 Impact Factor||0.296|
|2013 Impact Factor||0.326|
|2012 Impact Factor||0.42|
|2011 Impact Factor||0.379|
|2010 Impact Factor||0.459|
|2009 Impact Factor||0.512|
|2008 Impact Factor||0.554|
|2007 Impact Factor||0.656|
|2006 Impact Factor||0.5|
Impact factor over time
|Website||International Journal of Foundations of Computer Science website|
|Other titles||International journal of foundations of computer science (Online), Foundations of computer science|
|Material type||Document, Periodical, Internet resource|
|Document type||Internet Resource, Computer File, Journal / Magazine / Newspaper|
- Author can archive a pre-print version
- Author cannot archive a post-print version
- 12 months embargo
- Author's pre-print on any website or open access repository
- Author's post-print on author's personal website, institutional repository, subject repository or funding agency designated repository
- Publisher's version/PDF cannot be used
- Set statement to accompany pre-print and authors post-print - see policy
- Must link to publisher version with DOI
Publications in this journal
Article: Minimal and Hyper-Minimal Biautomata[Show abstract] [Hide abstract] ABSTRACT: We compare deterministic finite automata (DFAs) and biautomata under the following two aspects: structural similarities between minimal and hyper-minimal automata, and computational complexity of the minimization and hyper-minimization problem. Concerning classical minimality, the known results such as isomorphism between minimal DFAs, and NL-completeness of the DFA minimization problem carry over to the biautomaton case. But surprisingly this is not the case for hyper-minimization: the similarity between almost-equivalent hyper-minimal biautomata is not as strong as it is between almost-equivalent hyper-minimal DFAs. Moreover, while hyper-minimization is NL-complete for DFAs, we prove that this problem turns out to be computationally intractable, i.e., NP-complete, for biautomata.
Article: Scope-Bounded Pushdown Languages[Show abstract] [Hide abstract] ABSTRACT: We study the formal language theory of multistack pushdown automata (MPA) restricted to computations where a symbol can be popped from a stack S only if it was pushed within a bounded number of contexts of S (scoped MPA). We show that scoped MPA are indeed a robust model of computation, by focusing on the corresponding theory of visibly MPA (MVPA). We prove the equivalence of the deterministic and nondeterministic versions and show that scope-bounded computations of an n-stack MVPA can be simulated, rearranging the input word, by using only one stack. These results have some interesting consequences, such as, the closure under complement, the decidability of universality, inclusion and equality, and the effective semilinearity of the Parikh image (Parikh's theorem). As a further contribution, we give a logical characterization and compare the expressiveness of the scope-bounded restriction with other MVPA classes from the literature. To the best of our knowledge, scoped MVPA languages form the largest class of formal languages accepted by MPA that enjoys all the above nice properties.
- [Show abstract] [Hide abstract] ABSTRACT: We study a model where two opposing provers debate over the membership status of a given string in a language, trying to convince a weak verifier whose coins are visible to all. We show that the incorporation of just two qubits to an otherwise classical constant-space verifier raises the class of debatable languages from at most NP to the collection of all Turing-decidable languages (recursive languages). When the verifier is further constrained to make the correct decision with probability 1, the corresponding class goes up from the regular languages up to at least E. We also show that the quantum model outperforms its classical counterpart when restricted to run in polynomial time, and demonstrate some non-context-free languages which have such short debates with quantum verifiers.
- [Show abstract] [Hide abstract] ABSTRACT: We present a ring theoretic approach to Černý's conjecture via the Wedderburn-Artin theory. We first introduce the radical ideal of a synchronizing automaton, and then the natural notion of semisimple synchronizing automata. This is a rather broad class since it contains simple synchronizing automata like those in Černý's series. Semisimplicity gives also the advantage of "factorizing" the problem of finding a synchronizing word into the sub-problems of finding "short" words that are zeros into the projection of the simple components in the Wedderburn-Artin decomposition. In the general case this last problem is related to the search of radical words of length at most (n - 1)2 where n is the number of states of the automaton. We show that the solution of this "Radical Conjecture" would give an upper bound 2(n - 1)2 for the shortest reset word in a strongly connected synchronizing automaton. Finally, we use this approach to prove the Radical Conjecture in some particular cases and Černý's conjecture for the class of strongly semisimple synchronizing automata. These are automata whose sets of synchronizing words are cyclic ideals, or equivalently, ideal regular languages that are closed under taking roots.
- [Show abstract] [Hide abstract] ABSTRACT: Visibly pushdown transducers (VPTs) are visibly pushdown automata extended with outputs. They have been introduced oto model transformations of nested words, i.e. words with a call/return structure. When outputs are also structured and well nested words, VPTs are a natural formalism to express tree transformations evaluated in streaming. We prove the class of VPTs with well-nested outputs to be decidable in PTIME. Moreover, we show that this class is closed under composition and that its type-checking against visibly pushdown languages is decidable.
Article: Set Automata[Show abstract] [Hide abstract] ABSTRACT: We consider the model of deterministic set automata which are basically deterministic finite automata equipped with a set as an additional storage medium. The basic operations on the set are the insertion of elements, the removing of elements, and the test whether an element is in the set. We investigate the computational power of deterministic set automata and compare the language class accepted with the context-free languages and classes of languages accepted by queue automata. As result the incomparability to all classes considered is obtained. Furthermore, we examine the closure properties under several operations. Then we show that deterministic set automata may be an interesting model from a practical point of view by proving that their regularity problem as well as the problems of emptiness, finiteness, infiniteness, and universality are decidable. Finally, the descriptional complexity of deterministic and nondeterministic set automata is investigated. A conversion procedure that turns a deterministic set automaton accepting a regular language into a deterministic finite automaton is developed which leads to a double exponential upper bound. This bound is proved to be tight in the order of magnitude by presenting also a double exponential lower bound. In contrast to these recursive bounds we obtain non-recursive trade-offs when nondeterministic set automata are considered.
Article: Past Present[Show abstract] [Hide abstract] ABSTRACT: In 2014, the Development in Language Theory conference took place in the city of Yekaterinburg, in the Ural mountains of Russia. I used to live there. In Soviet times, there were no international conferences in the city. The whole region of the Urals was closed to foreigners. As I walked the streets of Yekaterinburg, I thought of my friends there and of Faulkner's lines “The past is never dead. It isn't even past.”
- [Show abstract] [Hide abstract] ABSTRACT: We analyze the average complexity of Brzozowski's minimization algorithm for distributions of deterministic automata with a small number of final states. We show that, as in the case of the uniform distribution, the average complexity is super-polynomial even if we consider random deterministic automata with only one final state. Such results were only known for distributions where the expected number of final states was linear in the number of states.
- [Show abstract] [Hide abstract] ABSTRACT: Heterogeneous multiprocessor architectures allow embedded real-time systems to better match computing resources to each application's needs and dynamic workload requirements, thereby providing many opportunities for improved performance with reduced power consumption. Unfortunately, guaranteeing real-time requirements on heterogeneous multiprocessors remains a critical problem due to the lack of appropriate scheduling algorithms and analysis methods. In this paper, we consider EDZL (Earliest Deadline First until Zero-Laxity) for performance asymmetric multiprocessor scheduling. EDZL has been shown to outperform other scheduling policies such as global EDF on identical multiprocessors. We show that EDZL is still effective on performance asymmetric multi-processors, and present an efficient EDZL schedulability test. Experimental results show that EDZL scheduling is able to schedule up to 20% more task sets than global EDF and that our new EDZL schedulability test can accept up to 30% more schedulable task sets than a presently exiting one.
- [Show abstract] [Hide abstract] ABSTRACT: The essential variables in a finite function f are defined as variables which occur in f and weigh with the values of that function. The number of essential variables is an important measure of complexity for discrete functions. When replacing some variables in a function with constants the resulting functions are called subfunctions, and when replacing all essential variables in a function with constants we obtain an implementation of this function. Such an implementation corresponds with a path in an ordered decision diagram (ODD) of the function which connects the root with a leaf of the diagram. The sets of essential variables in subfunctions of f are called separable in f. In this paper we study several properties of separable sets of variables in functions which directly affect the number of implementations and subfunctions in these functions. We define equivalence relations which classify the functions of k-valued logic into classes with the same number of: (i) implementations; (ii) subfunctions; and (iii) separable sets. These relations induce three transformation groups which are compared with the lattice of all subgroups of restricted affine group (RAG). This allows us to solve several important computational and combinatorial problems.
- [Show abstract] [Hide abstract] ABSTRACT: The frequency-hopping sequence set with low-hit-zone (LHZ FHS set) is useful for eliminating multiple-access interference in quasi-synchronous frequency-hopping multiple access systems. In this paper, basing on Cyclotomy, the discrete logarithm function and the Chinese remainder theorem, we construct two classes of LHZ FHS sets which have new parameters not covered in the literature. It is proved that proposed LHZ FHS sets are optimal respectively with respect to the Peng-Fan-Lee bounds.
- [Show abstract] [Hide abstract] ABSTRACT: A proxy signature scheme allows a proxy signer to sign messages on behalf of an original signer within a given context. We propose a certificateless proxy signature (CLPS) scheme, and prove it's security under a stronger security model. Although some good results were achieved in speeding up the computation of pairing function in recent years, it is still interesting to design cryptosystem with less pairing operations. Taken into account the computational costs, our scheme only requires 2 pairing operations in delegation and signing, respectively.
- [Show abstract] [Hide abstract] ABSTRACT: Two words are M-equivalent iff they are indistinguishable by Parikh matrices. Even for the ternary alphabet, an incontestable characterization of the M-equivalence relation is long overdue, ever since the introduction of Parikh matrices by Mateescu et al. in 2001. Recent works by Atanasiu attempted to distinguish M-equivalent words by the Parikh matrices of their images under some morphism. This paper addresses various aspects of this approach. In particular, it is shown that no morphism is capable of completely separating M-equivalent words over a given alphabet. However, if the class of words is restricted in length, then such morphism exists, whose codomain is connected to the notion of t-spectrum.
- [Show abstract] [Hide abstract] ABSTRACT: We consider a measure of similarity for infinite words that generalizes the usual number-theoretic notion of asymptotic or natural density for subsets of natural numbers. We show that every 73-power-free infinite binary word, other than the Thue-Morse word t and its complement t¯, has this measure of similarity with t between 13 and 23, and that this bound is optimal in a strong sense just for the class of overlap-free words. This is a generalization of a classical 1927 result of Kurt Mahler.
- [Show abstract] [Hide abstract] ABSTRACT: We study cooperating distributed grammar systems working in hybrid modes in connection with the finite index restriction in two different ways: firstly, we investigate cooperating distributed grammar systems working in hybrid modes which characterize programmed grammars with the finite index restriction; looking at the number of components of such systems, we obtain surprisingly rich lattice structures for the inclusion relations between the corresponding language families. Secondly, we impose the finite index restriction on cooperating distributed grammar systems working in hybrid modes themselves, which leads us to new characterizations of programmed grammars of finite index.
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.