Borderedness-preserving homomorphisms
This paper aims at investigating properties of homomorphisms which preserve the bordered words. The bordered words are classified into d1 d 1 -words and d2 d 2 -words, where the length of the proper border of d2 d 2 -word is greater than half of it. Some characterizations of d1 d 1 -word-preserving homomorphism are studied. Some relationships among d-primitivity-preserving homomorphisms, d1 d 1 -word-preserving homomorphisms, and d2 d 2 -word-preserving homomorphisms are investigated. We show that every d-primitivity-preserving homomorphism is d1 d 1 -word-preserving and every d1 d 1 -word-preserving homomorphism is d2 d 2 -word-preserving.
homomorphism combinatorial problems formal languages d-primitive primitive d1 d 1 -word d1 d 1 d1 d 1 d 1 d2 d 2 -word d2 d 2 d2 d 2 d 2 bifix code