Languages and P0L schemes

Abstract

Many systems involve substitutions between some sets of elements. The 0L system is a known technique which can help us to investigate properties of substitutions systematically. The aim of this paper is to establish some properties of the P0L schemes which preserve some types of properties of languages. Characterizations of pure-language-preserving, dense-preserving and palindrome-preserving P0L schemes are proposed. s-Injective, primitivity preserving, d-primitivity preserving, prefix code preserving and maximal prefix code preserving substitutions are also studied. Properties of dense-generating 0L schemes are also investigated.

Keywords:

• P0L scheme
• Property preserving substitution
• Primitive
• Palindrome
• Code

Acknowledgements

This work was supported by the National Science Council, R.O.C., under Grant NSC 90-2115-M-005-005.