A pumping lemma and decidability problems for recognizable tree series

In the present paper we show that given a tree series S, which is accepted by (a) a deterministic bottom-up finite state weighted tree automaton (for short: bu-w-fta) or (b) a non-deterministic bu-w-fta over a locally finite semiring, there exists for every input tree t E supp(S) a decomposition t =...

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Elmentve itt :
Bibliográfiai részletek
Szerző: Borchardt Björn
Testületi szerző: Conference on Hungarian Computational Linguistics (1.) (2003) (Szeged)
Dokumentumtípus: Cikk
Megjelent: 2004
Sorozat:Acta cybernetica 16 No. 4
Kulcsszavak:Számítástechnika, Nyelvészet - számítógép alkalmazása
Tárgyszavak:
Online Access:http://acta.bibl.u-szeged.hu/12739
Leíró adatok
Tartalmi kivonat:In the present paper we show that given a tree series S, which is accepted by (a) a deterministic bottom-up finite state weighted tree automaton (for short: bu-w-fta) or (b) a non-deterministic bu-w-fta over a locally finite semiring, there exists for every input tree t E supp(S) a decomposition t = C'[C[s]] into contexts C, C' and an input tree s as well as there exist semiring elements a, a', b, b', c such that the equation (S,C'[Cn[s]]) = a'OanOcObnOb' holds for every non-negative integer n. In order to prove this pumping lemma we extend the power-set construction of classical theories and show that for every non-deterministic bu-w-fta over a locally finite semiring there exists an equivalent deterministic one. By applying the pumping lemma we prove the decidability of a tree series S being constant on its support, S being constant, S being boolean, the support of S being the empty set, and the support of S being a finite set provided that S is accepted by (a) a deterministic bu-w-fta over a commutative semiring or (b) a non-deterministic bu-w-fta over a locally finite commutative semiring.
Terjedelem/Fizikai jellemzők:509-544
ISSN:0324-721X