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Statement

The paper's equation (1.2) (p. 374) is

x(x+1)⋯(x+k−1)=±2αzlx(x+1)\cdots(x+k-1)=\pm2^\alpha z^l

in rational numbers xx and z≥0z\ge0 and integers k≥2k\ge2, l≥2l\ge2 and α\alpha with −l<α<l-l<\alpha<l. The paper restricts to 0≤α<l0\le\alpha<l (p. 374), reducing a negative α\alpha to that range by a change of α\alpha and of zz to z/2z/2. The solutions x=−jx=-j, z=0z=0 with 0≤j<k0\le j<k, which occur for each α\alpha, are called trivial.

Theorem 3 (p. 375). Let 2≤k≤182\le k\le18 and l≥3l\ge3 with gcd⁡(l,k)=1\gcd(l,k)=1. If (1.2) holds with z≠0z\ne0, then k=2k=2 and

(x,z,α)∈{(−1/2,1/2,l−2), (−2,1,1), (1,1,1)}.(x,z,\alpha)\in\{(-1/2,1/2,l-2),\ (-2,1,1),\ (1,1,1)\}.

Source. K. Győry, L. Hajdu and N. Saradha, On the Diophantine equation n(n+d)⋯(n+(k−1)d)=byln(n+d)\cdots(n+(k-1)d)=by^l, Canad. Math. Bull. 47 (2004), no. 3, 373--388, doi:10.4153/CMB-2004-037-1; equation (1.2) on p. 374, Theorem 3 on p. 375, its proof on p. 384. The edition is recorded on the source card.

Read depth. Claims checked: the statement and the setting of (1.2) were read clause by clause against the published print, and the proof on p. 384 for its structure only. A second reader checked the statement, hypotheses, label and page against the print.

Proof pointer

Section 5, p. 384. Writing x=n/dx=n/d and z=y/y1z=y/y_1 in lowest terms turns (1.2) into the integral system (1.3) of p. 374, n(n+d)⋯(n+(k−1)d)=±2βuln(n+d)\cdots(n+(k-1)d)=\pm2^\beta u^l with vl=2γdkv^l=2^\gamma d^k and β+γ=α\beta+\gamma=\alpha, an instance of (1.1) with P(b)≤2P(b)\le2. Since gcd⁡(l,k)=1\gcd(l,k)=1, the second equation gives d=2hd1ld=2^hd_1^l with h≥0h\ge0, and Theorem 10 (p. 377) then yields the listed solutions.

Dependencies

Theorem 10 (p. 377) of the same paper, through Lemmas 2, 3 and 8 (pp. 377--379).

Bears on

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