English

Cantor set arithmetic

Metric Geometry 2017-11-27 v1 Number Theory

Abstract

Every element uu of [0,1][0,1] can be written in the form u=x2yu=x^2y, where x,yx,y are elements of the Cantor set CC. In particular, every real number between zero and one is the product of three elements of the Cantor set. On the other hand the set of real numbers vv that can be written in the form v=xyv=xy with xx and yy in CC is a closed subset of [0,1][0,1] with Lebesgue measure strictly between 1721\tfrac{17}{21} and 89\tfrac89. We also describe the structure of the quotient of CC by itself, that is, the image of C×(C{0})C\times (C \setminus \{0\}) under the function f(x,y)=x/yf(x,y) = x/y.

Cite

@article{arxiv.1711.08791,
  title  = {Cantor set arithmetic},
  author = {Jayadev S. Athreya and Bruce Reznick and Jeremy T. Tyson},
  journal= {arXiv preprint arXiv:1711.08791},
  year   = {2017}
}

Comments

Provisionally accepted by the American Mathematical Monthly

R2 v1 2026-06-22T22:55:22.150Z