Towards a Cardinality Theorem for Finite Automata

Kummer’s cardinality theorem states that a language is recursive if a Turing machine can exclude for any n words one of the n + 1 possibilities for the number of words in the language. This paper gathers evidence that the cardinality theorem might also hold for finite automata. Three reasons are given. First, Beigel’s nonspeedup theorem also holds for finite automata. Second, the cardinality theorem for finite automata holds for n = 2. Third, the restricted cardinality theorem for finite automata holds for all n.