Langages sur des alphabets infinis

AbstractThis paper proposes three possible definitions of context-free languages over infinite alphabets. These are proved to be non-equivalent and, in fact, of increasing power. For each of them, the classical results about CFL's as well as the usual closure properties are looked at. This work will be followed by two forthcoming papers using these notions: one for defining Languages' Form (similar to Grammars Form), the other for beginning the study of limits of languages which plays an important role in the theory of formal languages