• Publications
  • Influence
Conjunctive Grammars
  • A. Okhotin
  • Computer Science, Mathematics
  • J. Autom. Lang. Comb.
  • 1 April 2001
This paper introduces a class of formal grammars made up by augmenting the formalism of context-free grammars with an explicit set-theoretic intersection operation. It is shown that conjunctiveExpand
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On the State Complexity of Scattered Substrings and Superstrings
  • A. Okhotin
  • Computer Science, Mathematics
  • Fundam. Informaticae
  • 1 August 2010
It is proved that the set of scattered substrings of a language recognized by an n-state DFA requires a DFA with at least 2$^{n/2-2}$ states (the known upper bound is 2$^n$), with witness languagesExpand
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Non-erasing Variants of the Chomsky-Schützenberger Theorem
  • A. Okhotin
  • Computer Science, Mathematics
  • Developments in Language Theory
  • 14 August 2012
The famous theorem by Chomsky and Schutzenberger ("The algebraic theory of context-free languages", 1963) states that every context-free language is representable as h(Dk∩R), where Dk is the DyckExpand
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On the State Complexity of Star of Union and Star of Intersection
The state complexity of the star of union of an m-state DFA language and an n-state DFA language is proved to be 2 m+n−1−2 m−1−2 n−1+1 for every alphabet of at least two letters. The state complexityExpand
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Boolean grammars
  • A. Okhotin
  • Computer Science, Mathematics
  • Inf. Comput.
  • 1 October 2004
A new generalization of context-free grammars is introduced: Boolean grammars allow the use of all set-theoretic operations as an integral part of the formalism of rules. Rigorous semantics for theseExpand
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On the equivalence of linear conjunctive grammars and trellis automata
  • A. Okhotin
  • Computer Science, Mathematics
  • RAIRO Theor. Informatics Appl.
  • 2004
This paper establishes computational equivalence of two seemingly unrelated concepts: linear conjunctive grammars and trellis automata. Trellis automata, also studied under the name of one-wayExpand
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State complexity of power
The number of states in a deterministic finite automaton (DFA) recognizing the language L^k, where L is regular language recognized by an n-state DFA, and k>=2 is a constant, is shown to be at mostExpand
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On stateless multihead automata: Hierarchies and the emptiness problem
We look at stateless multihead finite automata in their two-way and one-way, deterministic and nondeterministic variations. The transition of a k-head automaton depends solely on the symbolsExpand
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On the closure properties of linear conjunctive languages
  • A. Okhotin
  • Computer Science, Mathematics
  • Theor. Comput. Sci.
  • 18 April 2003
Linear conjunctive grammars are conjunctive grammars in which the body of each conjunct contains no more than a single nonterminal symbol. They can at the same time be thought of as a special case ofExpand
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State complexity of cyclic shift
The cyclic shift of a language L , defined as SHIFT( L ) = { vu | uv ∈ L }, is an operation known to preserve both regularity and context-freeness. Its descriptional complexity has been addressed inExpand
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