• Publications
  • Influence
Conjunctive Grammars
  • A. Okhotin
  • Mathematics, Computer Science
  • J. Autom. Lang. Comb.
  • 1 April 2001
TLDR
It is proved that conjunctive grammars can still be parsed in cubic time and that the notion of the derivation tree is retained, which gives reasonable hope for their practical applicability. Expand
On the State Complexity of Scattered Substrings and Superstrings
  • A. Okhotin
  • Mathematics, Computer Science
  • 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
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
Non-erasing Variants of the Chomsky-Schützenberger Theorem
  • A. Okhotin
  • Mathematics, Computer Science
  • Developments in Language Theory
  • 14 August 2012
TLDR
If the Dyck language is augmented with neutral symbols, the characterization holds for every context-free language using a letter-to-letter homomorphism, as long as the language contains no one-symbol strings. Expand
On the equivalence of linear conjunctive grammars and trellis automata
  • A. Okhotin
  • Mathematics, Computer Science
  • RAIRO Theor. Informatics Appl.
  • 2004
TLDR
Their equivalence implies the equivalence of several other formal systems, including a certain restricted class of Turing machines and a certain type of language equations, thus giving further evidence for the importance of the language family they all generate. Expand
Boolean grammars
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
On stateless multihead automata: Hierarchies and the emptiness problem
TLDR
This work looks at stateless multihead finite automata in their two-way and one-way, deterministic and nondeterministic variations, and shows that the emptiness problem for stateless 2-head two- way automata is undecidable. Expand
Unambiguous finite automata over a unary alphabet
Nondeterministic finite automata (NFA) with at most one accepting computation on every input string are known as unambiguous finite automata (UFA). This paper considers UFAs over a one-letterExpand
On the closure properties of linear conjunctive languages
  • A. Okhotin
  • Computer Science, Mathematics
  • Theor. Comput. Sci.
  • 18 April 2003
TLDR
The closure properties of the language family generated by linear conjunctive grammars are investigated; the main result is its closure under complement, which implies that it is closed under all set-theoretic operations. Expand
State complexity of cyclic shift
TLDR
For 2- and 3-letter alphabets, it is proved 2 ⊖(n2) state complexity, and a tight 2n 2 + 1 lower bound is established for the nondeterministic state complexity of this operation using a binary alphabet. Expand
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