Searcharxiv⌕ Search

arXiv · math/0107067

Information, complexity and entropy: a new approach to theory and measurement methods

Abstract

In this paper, we present some results on information, complexity and entropy as defined below and we discuss their relations with the Kolmogorov-Sinai entropy which is the most important invariant of a dynamical system. These results have the following features and motivations: -we give a new computable definition of information and complexity which allows to give a computable characterization of the K-S entropy; -these definitions make sense even for a single orbit and can be measured by suitable data compression algorithms; hence they can be used in simulations and in the analysis of experimental data; -the asymptotic behavior of these quantities allows to compute not only the Kolmogorov-Sinai entropy but also other quantities which give a measure of the chaotic behavior of a dynamical system even in the case of null entropy.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Vieri Benci, Claudio Bonanno, Stefano Galatolo, Giulia Menconi, Federico Ponchio. 2001-07-10. Information, complexity and entropy: a new approach to theory and measurement methods. https://arxiv.org/abs/math/0107067

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Abelian maximal pattern complexity and extremal words

We study the Abelian maximal pattern complexity $p_{α}^{\ast \mathrm{ab}}(k)$ of infinite words over finite alphabets. For recurrent aperiodic words using exactly $\ell\geq 2$ letters, we prove the sharp lower bound $p_{α}^{\ast \mathrm{ab}}(k)\geq k+\ell-1$ and give a structural characterization of those words attaining equality for every $k\geq 1$. Without assuming recurrence, we prove that an infinite word $α$ is aperiodic if and only if $\binom{p_{α}^{\ast \mathrm{ab}}(k)}{2}\geq k$ for every positive integer $k$. For aperiodic words over $\ell\geq 2$ letters, each occurring infinitely often, we further prove that $p_α^{\ast \mathrm{ab}}(k)\geq m$ whenever $\binom{m}{2}\leq(\ell-1)(k-\ell+2)$, for all positive integers $m,k$. Together with a matching construction, this shows that the minimum Abelian maximal pattern complexity in this class is $\sqrt{2(\ell-1)k}+O_{\ell}(1)$. We call a word an Abelian pattern Sturmian word if, for every positive integer $k$, its Abelian maximal pattern complexity is the least positive integer $m$ satisfying $\binom{m}{2}\geq k$. We show that a word is Abelian pattern Sturmian if and only if, after relabeling its alphabet, it is the characteristic word of an infinite set $E\subset\mathbb{N}_0$ whose bipartite incidence graph is a forest. This graph has two disjoint copies of $\mathbb{N}_0$ as its vertex classes, with a left vertex $r$ adjacent to a right vertex $s$ exactly when $r+s\in E$.

math.DS↗

Spectral Dynamics and Fuglede--Kadison Determinants for Wreath Products

We investigate connections between operator spectra, complex dynamics, and determinants for wreath product groups. For a nontrivial finite abelian group $G$, the natural action of $G\wr\mathbb Z$ on a rooted tree produces a family of operators with a recursive structure. Applying Schur complements to this family yields a rational map on complex projective space. We determine the projective spectrum--the parameter values for which the operator pencil fails to be invertible--as the union of the Julia set of this map and an explicitly described subset of its Fatou set. We also prove that the associated Koopman representation and the left regular representation are weakly equivalent and therefore give the same projective spectrum. We then compute Fuglede--Kadison determinants for a family of operators on more general wreath products. These formulas yield injective operators with zero determinant for wreath products $K\wr\mathbb Z$, where $K$ is a discrete group admitting a nontrivial projection $e\in\mathbb C[K]$. This answers negatively a question of Li and Thom about whether injectivity implies positive determinant for operators defined by matrices over complex group rings of amenable groups. For $G_{tf}\rtimes_σ\mathbb Z$, where $G_{tf}$ is any countable torsion-free abelian group and $σ\in\operatorname{Aut}(G_{tf})$, we prove that injectivity does imply positive determinant in every matrix size.

math.DS↗

The fixed-point proportion of Lattès maps

How often does an element of the geometric iterated Galois group of a Lattès map fix a vertex of the tree? Let A/K be an abelian variety over a separably closed field of characteristic 0, G <= Aut(A,0) finite, and alpha an isogeny of degree at least 2 normalising G. The Lattès map on X=A/G has a preimage tree governed by alpha-power torsion; we determine the fixed-point proportion in every dimension. For zeta in G the weight is the reciprocal of the number of fixed points of zeta in alpha-power torsion (zero if infinite); equivalently, it is a product of p-adic absolute values of determinants on the alpha-active subspaces; for scalar alpha=m the proportion is (1/|G|) times the sum over 1 != zeta in G of the product over p dividing m of the p-adic absolute value of det(1 - zeta | H_1(A,Z)). We deduce positivity and vanishing criteria, prove the groups G_infinity are martingale groups, determine the limit law, and reduce groups with translations to the fixed-origin case. In dimension one we determine ten values for scalar multipliers and nontrivial G <= Aut(E,0), and for the eight quadratic Lattès classes the proportions are 1/8, 1/4 and 5/16. Bridy-Jones-Kelsey-Lodge exclude the Lattès case from their main theorem; their Theorem 2.5 periodic-point bound is attained, via reductions modulo split primes p = 1 (mod 4), for the map (x^2+a)/(x^2-a), a^2 = -1, and we settle the exceptional case of the Fariña-Asategui-Radi conjecture.

math.DS↗