SearcharxivSearch

arXiv · 2309.16833

Models for gaps $g=2p_1$

Abstract

We have shown previously that at each stage of Eratosthenes sieve there is a corresponding cycle of gaps $\mathcal{G}(p_0^\#)$. We can view these cycles of gaps as a discrete dynamic system, and from this system we can obtain exact models for the populations and relative populations of gaps $g < 2p_1$ if we can get the initial conditions from $\mathcal{G}(p_0^\#)$. In this addendum we have shown that we can produce the model for $g=2p_1$ from these initial conditions. This model requires one special iteration to track the count from $\mathcal{G}(p_0^\#)$ to $\mathcal{G}(p_1^\#)$, after which we can use the general model for these populations. As a specific example we exhibit the model for the gap $g=82$ using $\mathcal{G}(37^\#)$ for initial conditions. We show further that in order to produce the models for $g=2p_1+2$ and beyond from initial conditions in $\mathcal{G}(p_0^\#)$, we would have to track subpopulations of the driving terms until the general model applies, that is until $g < 2p_{k+1}$. This work serves as an addendum to the existing references "Patterns among the Primes" and "Combinatorics of the gaps between primes". We do not duplicate that background here, beyond summarizing a few needed results.

Explore related subjects

Keep this discovery

BibTeXRIS

Fred B. Holt. 2023-09-28. Models for gaps $g=2p_1$. https://arxiv.org/abs/2309.16833

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

KEEP EXPLORING

Related papers

Average Chord Lengths in a Triangle

Let $P$ be a point inside a triangle $T$. We consider the average length of the chords of $T$ through $P$, where the direction of the chord is chosen uniformly. An elementary formula is obtained in terms of the distances from $P$ to the sides and vertices of the triangle. Several classical triangle centers give especially simple specializations. For example, if $I$ is the incenter, then \[ M_T(I)=\frac{2r}{\pi} \log\left(\cot\frac A4\cot\frac B4\cot\frac C4\right). \] Our main result is the sharp inequality \[ M_T(P)\le \frac{p}{\pi\sqrt3}\log(2+\sqrt3), \] valid simultaneously for every triangle of perimeter $p$ and every interior point $P$. Thus, among all such pairs $(T,P)$, the largest possible average chord length occurs only when $T$ is equilateral and $P$ is its center. The proof is an elementary symmetrization argument. We close with brief remarks relating the problem to the radial center of a convex body, the electrostatic potential center of a triangle, and dual quermassintegrals.

math.GM

A Proof of Liu's Conjecture on the Fundamental Triangle Inequality

Let $a,b,c$ be the side lengths of a triangle, and let $R$ and $r$ denote its circumradius and inradius, respectively. We prove a conjecture of Liu stating that \[\sum_{\mathrm{cyc}} \left(\frac{a(b+c-a)}{bc}\right)^k \geq 2+\left(\frac{2r}{R}\right)^k,~~k>1, \] with the reverse inequality for $0<k<1$. The proof reduces the problem to three positive variables with fixed sum and product. We also determine the equality cases.

math.GM