THE CLOSEDNESS OF TYPE 3 LANGUAGE CLASS UNDER S-MAPPING
Jianbo Su · Chinese Journal of Computers · 1982
One of the problems of formal language theory is the study of the closedness of various language classes under various operations and mappings. In this paper, we give two proofs of the closedness of type 3 language class under S-mappingA mapping a from V to 2w is called an S-mapping if and only if the mapping a is a substitution such that the family of sets {σ(x)|XeV} is a partition of the setW.