Peter Stoll | Searcharxiv

arXiv2021

The repetends of reduced fractions $a/b^k$ approach full complexity with an increasing $k$

In this paper, we prove a criterion for complexity in $g$-ary expansions of a rational fraction $a/b<1$ with gcd$(a,b)=1$. We prove that for any purely periodic proper fraction $a/b$ and all $j\geq 1$, each sequence of $j$ digits occurs in the $g$-ary repetend of $a/b^k$ with a relative frequency that approaches $1/g^j$ with an increasing $k$. The absolute frequencies can be calculated by means of a simple transition matrix. Let $(a_k)$ be a sequence of positive integers relatively prime to $b$. We prove that each sequence of $j$ digits occurs in the $g$-ary repetend of $a_k/b^k$ with a relative frequency that approaches $1/g^j$ with an increasing $k$, unless all prime factors of $b$ divide the base $g\geq 2$.

math.NT↗

arXiv2021

The 3x+1 Periodicity Conjeture in $\mathbb{R}$

The $3x+1$ map $T$ is defined on the $2$-adic integers $\mathbb{Z}_2$ by $T(x)=x/2$ for even $x$ and $T(x)=(3x+1)/2$ for odd $x$. It is still unproved that under iteration of $T$ the trajectory of any rational $2$-adic integer is eventually cyclic. A $2$-adic integer is rational if and only if its representation with $1$'s and $0$'s is eventually periodic. We prove that the $3x+1$ conjugacy $\Phi$ maps aperiodic $v\in\mathbb{Z}_2$ onto aperiodic $2$-adic integers provided that $\underline{\lim}\;(\frac{h}{\ell})_{\ell=1}^{\infty} > \frac{\ln(2)}{\ln(3)}$ where $h$ is the number of $1$'s in the first $\ell$ digits of $v$ with the following constraint: if there is a rational $2$-adic integer with a non-cyclic trajectory, then necessarily $\underline{\lim}\;(\frac{h}{\ell})_{\ell=1}^{\infty}=\frac{\ln(2)}{\ln(3)}$. We study $\Phi$ as an infinite series in $\mathbb{R}$ and obtain negative irrational numbers for which we compute their aperiodic $2$-adic expansion. We find prominent behaviors of the orbit of $x$ taking Sturmian words as parity vector. We also found amazing results of the terms of $\Phi$ in $\mathbb{R}$. We define the $\ell$'th iterate of $T$ for $\ell\rightarrow \infty$ in the ring of $3$-adic integers and obtain positive irrational numbers for which we compute their aperiodic $3$-adic expansion.

math.NT↗