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 alphab...

Let $k$ be a field, let ${\sf C}$ $k$-linear abelian category, $\underline{\mathcal{L}}:=\{\mathcal{L}_{i}\}_{i \in \mathbb{Z}}$ sequence of objects in C}$, and $B_{\underline{\mathcal{L}}}$ the associated orbit algebra. We describe sufficient conditions on $\underline{\mathcal{L}}$ such that there is canonical morphism from noncommutative space Proj }B_{\underline{\mathcal{L}}}$ to projective ...