On Morphisms Preserving Palindromic Richness

It is known that each word of length n contains at most + 1 distinct palindromes. A finite rich a with maximal number palindromic factors. The definition richness can be naturally extended to infinite words. Sturmian words and Rote complementary symmetric sequences form two classes binary words, while episturmian coding d-interval exchange transformations give us other examples on larger alphabets. In this paper we look for morphisms the free monoid, which allow construct new from already We focus in Class Pret. This class injective alphabet satisfying particular palindromicity property: every morphism ? there exists palindrome w such ?(a)w first complete return letter a. characterize Pret preserve over alphabet. also study marked acting alphabets more letters. show Arnoux-Rauzy conjugated it preserves richness.