Functors and ordinal notations I : a functorial construction of the Veblen hierarchy
Résumé
This paper is the first of several works: the matter is the systematic rewriting of usual results of ordinal notations, using Pi-1-2-logic. The purpose of these articles is already realized in Pi-1-2-logic, in a relatively abstract form. The paper presents a functorial construction of the Veblen hierarchy.