Wiki
Wiki

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

Updated


Statement

Question (1) (p. 378, quoted). "Can the inequalities pn+1−pn<pn+2−pn+1<⋯<pn+k−pn+k−1p_{n+1}-p_n<p_{n+2}-p_{n+1}<\cdots<p_{n+k}-p_{n+k-1} have infinitely many solutions for every fixed kk?"

The chain compares the kk consecutive gaps that start at pnp_n. The paper poses it as an open question. Its case k=2k=2 follows from the first system (6) of the Lemma (p. 372) without its size condition.

The paper's second closing question (p. 378) asks whether the number of k≤nk\le n with pk+1−pk>pk−pk−1p_{k+1}-p_k>p_k-p_{k-1} is n/2+o(n)n/2+o(n); it says, without giving a proof, that it can show this number lies between c1nc_1n and (1−c1)n(1-c_1)n.

Read depth. Claims checked: both closing questions and the stated count were read clause by clause on the page image of p. 378 of the print. Nothing here is independently reviewed.

Proof pointer

None: an open question in the paper.

Dependencies

None.

Source. P. Erdős and P. Turán, On some new questions on the distribution of prime numbers, Bull. Amer. Math. Soc. 54 (1948), 371--378; the edition read is named on the source card.

Bears on

  • Problem 6: the case k=3k=3 of the question, infinitely many nn with dn<dn+1<dn+2d_n<d_{n+1}<d_{n+2} where dn=pn+1−pnd_n=p_{n+1}-p_n, is the problem's statement; the problem page lists the paper among its references.