Nonconstructive
Language Recognition
by Finite Automata
Kaspars Balodis, Rusins Freivalds, Lauma
Pretkalnina, Inga Rumkovska, Madars Virza
Nonconstructive Language
Recognition
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Two-way automaton equipped with an
additional tape where nonconstructive help
(advice) is fed in
For every word length n there is a help y(n)
Given a correct help y(n) automaton should
give correct answer to any word x whose
length does not exceed n
Amount of nonconstructivity (minimal length
of help words |y(n)|) to recognize a language
L is considered
Our results
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Tight upper bound Θ(2n) of amount of
nonconstructivity that can be needed to
recognize a language
Results on multi-tape finite automata
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Nonregular language that can be recognized with
nonconstructivity O(ln n) on 2 tapes
A Turing machine using space f(n) can be
simulated with an automaton using
nonconstructivity cf(n) on 4 tapes
Thank you!
See you at the poster!