Do Long Van Langages écrits par un code infinitaire. Théorème du défaut. (French) Zbl 0611.68046 Acta Cybern. 7, 247-257 (1986). If C is a class of (infinitary) codes, a language X is said to be written by a C-code if there is a \(Y\in C\) such that \(X\subseteq Y^*\). The author characterizes infinitary languages written by arbitrary codes, normal codes, prefix codes, and suffix codes. The basis of the quasi-free monoid generated by an infinitary language X written by a code has less elements than X has if X itself is not a code (”Theorem of defect”). A recognizable infinitary language written by a code can also be written by a recognizable code. Reviewer: M.Armbrust Cited in 1 Document MSC: 68Q45 Formal languages and automata 20M35 Semigroups in automata theory, linguistics, etc. 94A45 Prefix, length-variable, comma-free codes Keywords:infinitary code; infinitary languages; quasi-free monoid PDF BibTeX XML Cite \textit{Do Long Van}, Acta Cybern. 7, 247--257 (1986; Zbl 0611.68046) OpenURL