{ "id": "2102.10093", "version": "v1", "published": "2021-02-19T18:48:29.000Z", "updated": "2021-02-19T18:48:29.000Z", "title": "Almost everywhere balanced sequences of complexity $2n+1$", "authors": [ "Julien Cassaigne", "Sébastien Labbé", "Julien Leroy" ], "comment": "41 pages, 9 figures. Extended and augmented version of arXiv:1707.02741", "categories": [ "math.DS", "math.CO" ], "abstract": "We study ternary sequences associated with a multidimensional continued fraction algorithm introduced by the first author. The algorithm is defined by two matrices and we show that it is measurably isomorphic to the shift on the set $\\{1,2\\}^\\mathbb{N}$ of directive sequences. For a given set $\\mathcal{C}$ of two substitutions, we show that there exists a $\\mathcal{C}$-adic sequence for every vector of letter frequencies or, equivalently, for every directive sequence. We show that their factor complexity is at most $2n+1$ and is $2n+1$ if and only if the letter frequencies are rationally independent if and only if the $\\mathcal{C}$-adic representation is primitive. It turns out that in this case, the sequences are dendric. We also prove that $\\mu$-almost every $\\mathcal{C}$-adic sequence is balanced, where $\\mu$ is any shift-invariant ergodic Borel probability measure on $\\{1,2\\}^\\mathbb{N}$ giving a positive measure to the cylinder $[12121212]$. We also prove that the second Lyapunov exponent of the matrix cocycle associated to the measure $\\mu$ is negative.", "revisions": [ { "version": "v1", "updated": "2021-02-19T18:48:29.000Z" } ], "analyses": { "subjects": [ "37B10", "68R15", "11J70", "37H15" ], "keywords": [ "balanced sequences", "complexity", "shift-invariant ergodic borel probability measure", "adic sequence", "letter frequencies" ], "note": { "typesetting": "TeX", "pages": 41, "language": "en", "license": "arXiv", "status": "editable" } } }