Journal of Mathematical Analysis and Applications 95(2), pp. 375-378.
ISSN/ISBN: Not available at this time. DOI: 10.1016/0022-247X(83)90113-0
Abstract: For any k∈I^{+} = the set of positive integers, let S(k) denote the set of positive integers beginning with k, i.e., S(k) = { n: k = ⎣n/10^{r}⎦for some r∈I^{+}}, where ⎣x⎦ denotes the greatest integer less than or equal to x. Consider some finitely additive extension of the density function d(S) = lim_{N→∞} |S∩[1, N]|/N, where S⊂I^{+} and |S| denotes the cardinality of S. If d(k) = d(S(k)) is defined for all positive integers k, and if the mapping T that maps S into (2S)∪(2S + 1) preserves the density d, then the result of Cohen is that d(p) = log_{10}(1 + (1/p)) for p∈D. The crucial step here is the specific relation of the transformation T to the multiplication of the elements of S by 2. This motivates us to consider the following problem: Set b = 10 and let a∈R^{+} be a positive real number. Let θ(x) = ax, where x∈R^{+}, and consider the sequence p = (p_{1}, p_{2},...) of first digits of the orbit of θ: { x, θ(x), θ^{2}(x), ...}. That is, p_{k} = ⎣θ^{k}(x)/b^{r}⎦∈D, where r=⎣log_{10}θ^{k}(x)⎦. The purpose of this paper is to investigate the dynamical properties of the sequence p.
Bibtex:
@article{,
title={First digit phenomenon and ergodic theory},
author={Robertson, James B and Uppuluri, VRR and Rajagopal, AK},
journal={Journal of mathematical analysis and applications},
volume={95},
number={2},
pages={375--378},
year={1983},
publisher={Elsevier},
DOI={10.1016/0022-247X(83)90113-0},
}
Reference Type: Journal Article
Subject Area(s): Dynamical Systems