Formal Languages and Automata VI:-algebraic systems and transducers
... starsemiring-omegasemimodule pairs. We dene !-algebraic systems and characterize their solutions
of order k by behaviors of algebraic nite automata. These solutions are then set in correspondence to !-context-free languages. Then we introduce rational and algebraic transducers, and abstract !-families of power series over quemirings and prove that rational and algebraic power series of nite and innite words constitute such abstract !-families of power series.
6. Berstel J. Transductions and Context-Free Languages....