Пятница, 9 декабря, ауд. 311. Начало в 17:00.
Докладчик: Galina Jiraskova (Mathematical Institute Slovak Academy of Sciences).
Тема: Self-Verifying Finite Automata.
Abstract
Consider a nondeterministic finite automaton
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where the states can be either accepting, rejecting, or neutral. Let
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TeX Embedding failed! is said to be self-verifying
if
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TeX Embedding failed!.
That is, the strings reaching an accepting state and the strings reaching a rejecting state form a disjoint partition of
TeX Embedding failed!. The language accepted by
TeX Embedding failed! is
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Using a result of Moon, Moser [On cliques in graphs, Israel J. Math. 3, 23--28, 1965], we get an optimal simulation of self-verifying automata by deterministic finite automata. Then we study the complexity of regular operations on languages represented by self-verifying automata, and get the tight upper bounds for union (
TeX Embedding failed!), intersection (
TeX Embedding failed!), reversal (
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TeX Embedding failed!), right quotient (
TeX Embedding failed!), and asymptotically tight upper bound for concatenation (
TeX Embedding failed!). Next we prove that given a nondeterministic automaton
TeX Embedding failed! with accepting, rejecting, and neutral states, it is PSPACE-complete to determine if
TeX Embedding failed! is self-verifying. Finally, we study the complexity of the membership, emptiness, universality, and minimization problems for self-verifying automata.