Wiki
Wiki

Research notes on every problem, and a library of the papers behind them. Built from the open erdos repository.

Updated


Statement

Setting (p. 340, §6). Take a number α\alpha with log⁡2<α<1\log2<\alpha<1 and "a sequence of positive integers"

n1,n2=n11+log⁡−αn1,…,ni+1=ni1+log⁡−αni,…n_1,\quad n_2=n_1^{1+\log^{-\alpha}n_1},\quad\ldots,\quad n_{i+1}=n_i^{1+\log^{-\alpha}n_i},\quad\ldots

(as printed, with log⁡−αni=(log⁡ni)−α\log^{-\alpha}n_i=(\log n_i)^{-\alpha}; the paper does not say how the right sides are made integers). Let mim_i be the density of the set of integers with a divisor ≥ni\geq n_i and <ni+1<n_{i+1}.

Theorem 2 (p. 340, quoted).

m1+m2+⋯+ml=o(l).m_1+m_2+\cdots+m_l=o(l).

The limit is l→∞l\to\infty. The paper calls this theorem "much stronger than Theorem 1" and gives no separate proof: "the proof is practically identical with the proof of Theorem 1" (p. 340).

Source. A. S. Besicovitch, "On the density of certain sequences of integers," Mathematische Annalen 110 (1935), 336--341, https://doi.org/10.1007/BF01448032: Theorem 2 and the remark after it on p. 340. The edition read is identified on the source card.

Read depth. Claims checked: the hypotheses and the statement were read on the printed page. The paper prints no proof, and none was checked here. Nothing here is independently reviewed.

Proof pointer

None in the paper beyond the remark that the proof of Theorem 1 (pp. 339--340) carries over.

Dependencies

The proof of Theorem 1 of the same paper, by the paper's remark.