algorithm,parsing,string-matching,formal-languages,kleene-star

This problem is equivalently stated as: when is L a code over Σ? The standard algorithm for determining this is the Sardinas-Patterson algorithm, published in 1953. There is an interesting discussion in the book review by Juhani Karhumäki (Bulletin of the AMS, vol. 17 no. 1, pp. 161-167, 1987) of...