SearcharxivSearch

arXiv · 0906.2972

Distributive properties of the rationals

Abstract

If o and * are two binary operations in a number system, then three elements a,b,c in that number system are said to satisfy the distributive property of the operation o over the operation * if, ao(b*c)= (aob)*(aoc) Now, suppose that the number system is the rationals,and the operations o and * are among the four usual operations of addition, multiplication, subtraction, and division. If we allow for o and * to be the same operation, then there are precisely 16 combinations with the operation o being one of the four usual operations in Q; and likewise for the operation *. Two of these 16 combinations are when o is the multiplication operationand * being the addition operation; and when is o is multiplication and * is subtraction. For these two combinations, the above stated distributive property is universally satisfied; that is, for ane three rational numbers a,b,and c. In this work, we examine the other fourteen combinations, to find out when the distributive property is satisfied. Of these 14 combinations or cases, eleven are easy/straightforward, in that almost always, one of the three rational numbers a, b, c; must be zero or 1. The remaining three cases or combinations are much more complicated, and number theory is involved.

Explore related subjects

Keep this discovery

BibTeXRIS

Konstantine Zelator. 2009-06-16. Distributive properties of the rationals. https://arxiv.org/abs/0906.2972

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