English

Rough integers with a divisor in a given interval

Number Theory 2022-07-05 v2

Abstract

We determine, up to multiplicative constants, the number of integers nxn\le x that have no prime factor w\le w and a divisor in (y,2y](y,2y]. Our estimate is uniform in x,y,wx,y,w. We apply this to determine the order of the number of distinct integers in the N×NN\times N multiplication table which are free of prime factors w\le w, and the number of distinct fractions of the form a1a2b1b2\frac{a_1a_2}{b_1b_2} with 1a1b1N1\le a_1 \le b_1\le N and 1a2b2N1\le a_2\le b_2 \le N.

Keywords

Cite

@article{arxiv.1901.02548,
  title  = {Rough integers with a divisor in a given interval},
  author = {Kevin Ford},
  journal= {arXiv preprint arXiv:1901.02548},
  year   = {2022}
}

Comments

v2. Corrected typos and rewrote Section 4 to make more clear the relationship between various parameters

R2 v1 2026-06-23T07:06:35.484Z