Research output: Contribution to journal › Article › peer-review
Edit distance neighbourhoods of input-driven pushdown automata. / Okhotin, Alexander; Salomaa, Kai.
In: Theoretical Computer Science, Vol. 777, 19.07.2019, p. 417-430.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Edit distance neighbourhoods of input-driven pushdown automata
AU - Okhotin, Alexander
AU - Salomaa, Kai
PY - 2019/7/19
Y1 - 2019/7/19
N2 - Edit distance ℓ-neighbourhood of a formal language is the set of all strings that can be transformed to one of the strings in this language by at most ℓ insertions and deletions. Both the regular and the context-free languages are known to be closed under this operation, whereas the family recognized by deterministic pushdown automata is not. This paper establishes the closure of the family recognized by input-driven pushdown automata (IDPDA), also known as visibly pushdown automata, under the edit distance neighbourhood operation. For an n-state nondeterministic IDPDA with n stack symbols, an automaton for its edit distance ℓ-neighbourhood using O(nℓ+1) states is constructed, and an asymptotically matching lower bound is established. For an n-state deterministic IDPDA, its 1-neighbourhood in the worst case requires a deterministic IDPDA with at least 2Ω(n2) states.
AB - Edit distance ℓ-neighbourhood of a formal language is the set of all strings that can be transformed to one of the strings in this language by at most ℓ insertions and deletions. Both the regular and the context-free languages are known to be closed under this operation, whereas the family recognized by deterministic pushdown automata is not. This paper establishes the closure of the family recognized by input-driven pushdown automata (IDPDA), also known as visibly pushdown automata, under the edit distance neighbourhood operation. For an n-state nondeterministic IDPDA with n stack symbols, an automaton for its edit distance ℓ-neighbourhood using O(nℓ+1) states is constructed, and an asymptotically matching lower bound is established. For an n-state deterministic IDPDA, its 1-neighbourhood in the worst case requires a deterministic IDPDA with at least 2Ω(n2) states.
KW - Edit distance
KW - Input-driven automata
KW - State complexity
KW - Visibly pushdown automata
KW - STATE COMPLEXITY
KW - LANGUAGES
UR - http://www.scopus.com/inward/record.url?scp=85062951701&partnerID=8YFLogxK
U2 - 10.1016/j.tcs.2019.03.005
DO - 10.1016/j.tcs.2019.03.005
M3 - Article
AN - SCOPUS:85062951701
VL - 777
SP - 417
EP - 430
JO - Theoretical Computer Science
JF - Theoretical Computer Science
SN - 0304-3975
ER -
ID: 43676311