We initiate the theory and applications of biautomata. A biautomaton can read a word alternately from the left and from the right. We assign to each regular language L its canonical biautomaton. This structure plays, among all biautomata recognizing the language L, the same role as the minimal deterministic automaton has among all deterministic automata recognizing the language L. We expect that from the graph structure of this automaton one could decide the membership of a given language for certain significant classes of languages. We present the first two results of this kind: namely, a language L is piecewise testable if and only if the canonical biautomaton of L is acyclic. From this result Simon's famous characterization of piecewise testable languages easily follows. The second class of languages characterizable by the graph structure of their biautomata are prefix-suffix testable languages.
Mots clés : biautomata, canonical biautomaton, piecewise testable languages, prefix-suffix languages
@article{ITA_2012__46_4_573_0, author = {Kl{\'\i}ma, Ond\v{r}ej and Pol\'ak, Libor}, title = {On biautomata}, journal = {RAIRO - Theoretical Informatics and Applications - Informatique Th\'eorique et Applications}, pages = {573--592}, publisher = {EDP-Sciences}, volume = {46}, number = {4}, year = {2012}, doi = {10.1051/ita/2012014}, mrnumber = {3107864}, zbl = {1279.68238}, language = {en}, url = {http://archive.numdam.org/articles/10.1051/ita/2012014/} }
TY - JOUR AU - Klíma, Ondřej AU - Polák, Libor TI - On biautomata JO - RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications PY - 2012 SP - 573 EP - 592 VL - 46 IS - 4 PB - EDP-Sciences UR - http://archive.numdam.org/articles/10.1051/ita/2012014/ DO - 10.1051/ita/2012014 LA - en ID - ITA_2012__46_4_573_0 ER -
%0 Journal Article %A Klíma, Ondřej %A Polák, Libor %T On biautomata %J RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications %D 2012 %P 573-592 %V 46 %N 4 %I EDP-Sciences %U http://archive.numdam.org/articles/10.1051/ita/2012014/ %R 10.1051/ita/2012014 %G en %F ITA_2012__46_4_573_0
Klíma, Ondřej; Polák, Libor. On biautomata. RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications, Tome 46 (2012) no. 4, pp. 573-592. doi : 10.1051/ita/2012014. http://archive.numdam.org/articles/10.1051/ita/2012014/
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