On ω-languages of special billiards
Boris Feliksovich Melnikov · Discrete Mathematics and Applications · 2002
Abstract We consider non-deterministic initial finite automata without final states and the ω-languages determined by such automata. For such ω-languages, we consider the so-called languages of obstructions. We define and analyse billiard ω-languages determined in a special way for each n ≥ 3 over an alphabet consisting of n letters. Each ω-word of such ω-language can be obtained with the use of infinite number of reflections of a point from the cushions of billiards having the form of a regular n-polygon. For such ω-languages, we consider the languages of obstructions and show that for any n a language of obstructions is not regular.