A Note on Realtime One-Way Synchronized Alternating One-Counter Automata

Hromko\ii-. J. and K. Inoue. A note on realtime one-\\ay synchronized alternating one-counter automata. Theoretical Computer Science 108 (1993) 393-400. This paper investigates the poner of realtime one-\+a> synchronized alternating one-counter automata (lsaca (1. real)sL and shous that (1) lsacall. realis are more powerful than real-time one-way nondeterministic multlcounter automata. and (7) there exists a language accepted b! a lsaca(1. real). but not accepted b) an) realtime one-wa) alternating multi-stack-counter automata. As a corollary of 12). He habe: for each k> I. realtime one-way synchronized alternating k-counter ik-stack-counter) automata are more powerful than realtime one-aa> alternating kcounter (k-stack-counter) automata. We. finall). show that realtime synchronized alternating finite automata recognize esactlq regular sets. i.e.. that one counter is more powerful than no counter for realtime sgnchronizrd alternating automata. Correspondence 10: J. Hromko\lL Department of Computer Science, Comenius Uni\erslty. 842 15 Bratislava. Czechoslovakia. and Fachberelch 17 Mathematlk-Informatik. Unikersitat-GH Paderborn. 4790 Paderborn, German>. *This work was done during the stay of the first author at Yamaguchi University. 0304-3975/93/$06.00 c 1993-Ellsevler Science Publishers B.V. All rights reserved