The main result of this paper is: Let L be a full principal AFL closed under context-free substitution. Then there is a fixed language l0 in L such that for each L in L there exist a weak coding h and a homomorphism g such that L = hg-1(L0). As a corollary, it immediately follows that there is a fixed ETOL language L0 such that for each ETOL language L there exist a weak coding h and a homomorphism g such that L = hg-1(L0).
ASJC Scopus subject areas
- Control and Systems Engineering
- Theoretical Computer Science
- Computer Science Applications
- Information Systems and Management
- Artificial Intelligence