Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Fundamenta Informaticae

Powiadomienia systemowe

Sesja wygasła!

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: counter automata

Sortuj według:

Ogranicz wyniki do:

Minimal Size of Counters for (Real-Time) Multicounter Automata

Geffert Viliam, Bednárová Zuzana

Fundamenta Informaticae

2021

Vol. 181, nr 2-3

99--127

We show that, for automata using a finite number of counters, the minimal space that is required for accepting a nonregular language is (log n)ɛ. This is required for weak space bounds on the size of their counters, for real-time and one-way, and for nondeterministic and alternating versions of these automata. The same holds for two-way automata, independent of whether they work with strong or weak space bounds, and of whether they are deterministic, nondeterministic, or alternating. (Here ɛ denotes an arbitrarily small — but fixed-constant; the “space” refers to the values stored in the counters, rather than to the lengths of their binary representation.) On the other hand, we show that the minimal space required for accepting a nonregular language is nɛ for multicounter automata with strong space bounds, both for real-time and one-way versions, independent of whether they are deterministic, nondeterministic, or alternating, and also for real-time and one-way deterministic multicounter automata with weak space bounds. All these bounds are optimal both for unary and general nonregular languages. However, for automata equipped with only one counter, it was known that one-way nondeterministic automata cannot recognize any unary nonregular languages at all, even if the size of the counter is not restricted, while, with weak space bound log n, we present a real-time nondeterministic automaton recognizing a binary nonregular language here.

Relating Reachability Problems in Timed and Counter Automata

Haase C., Ouaknine J., Worrell J.

Fundamenta Informaticae

2016

Vol. 143, nr 3/4

317--338

We establish a relationship between reachability problems in timed automata and spacebounded counter automata. We show that reachability in timed automata with three or more clocks is logarithmic-space inter-reducible with reachability in space-bounded counter automata with two counters. We moreover show the logarithmic-space equivalence of reachability in two-clock timed automata and space-bounded one-counter automata. This last reduction has recently been employed by Fearnley and Jurdziński to settle the computational complexity of reachability in two-clock timed automata.