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

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Claim. A. Schinzel and E. Wirsing, Multiplicative properties of the partition function, Proc. Indian Acad. Sci. Math. Sci. 97 (1987), nos. 1–3, 297–303. Write m(N,N+R)m(N,N+R) for the number of multiplicatively independent values of p(n)p(n) in N≤n<N+RN\le n<N+R, and m(N)m(N) for that number in 1≤n≤N1\le n\le N. The paper's Theorem states that there is an N0N_0 such that

m(N,N+R)≥R log⁡N−log⁡R32log⁡N+Rlog⁡2m(N,N+R)\ge R\,\frac{\log N-\log R}{\tfrac32\log N+R\log2}

for N≥N0N\ge N_0 and all R∈NR\in\mathbb N, and that the same lower bound applies to the number of distinct prime factors of ∏N≤n<N+Rp(n)\prod_{N\le n<N+R}p(n). Its Corollary 2 gives m(N,N+R)≥(1/log⁡2−o(1))log⁡Nm(N,N+R)\ge(1/\log2-o(1))\log N when R/log⁡N→∞R/\log N\to\infty, and the paper then states that

ω(∏n=1Np(n))≥m(N)≥(1−ε)log⁡Nlog⁡2(N≥N0(ε)).\omega\Bigl(\prod_{n=1}^{N}p(n)\Bigr)\ge m(N)\ge(1-\varepsilon)\frac{\log N}{\log2} \qquad(N\ge N_0(\varepsilon)).

The left side is F(N)F(N), the number of distinct prime factors of p(1)p(2)⋯p(N)p(1)p(2)\cdots p(N) in Problem 1106, so F(n)≥(1−ε)log⁡n/log⁡2F(n)\ge(1-\varepsilon)\log n/\log2 for all large nn, and in particular F(n)≫log⁡nF(n)\gg\log n; the site's commentary and the formal-conjectures entry both credit that bound to this paper. The inequality ω≥m\omega\ge m is elementary: positive integers built from ss primes lie in a free abelian group of rank ss, so rr multiplicatively independent values force at least rr distinct primes. Ono [On00] cites the paper for the bound ≫log⁡log⁡X\gg\log\log X on the number of primes m<Xm<X that divide some p(n)p(n).

Covers. The first question: F(n)→∞F(n)\to\infty, at the rate F(n)≥(1−ε)log⁡n/log⁡2F(n)\ge(1-\varepsilon)\log n/\log2. The second question, whether F(n)>nF(n)>n for all large nn, is not addressed.

Depends on. No page of this wiki: the bound on F(n)F(n) is stated in the paper.

Acceptance. Refereed: the paper appeared in Proceedings of the Indian Academy of Sciences (Mathematical Sciences) in December 1987. The site's commentary credits F(n)≫log⁡nF(n)\gg\log n to this paper, but the site labels the problem OPEN, so the commentary is not acceptance and no reviewed is listed. The formal-conjectures file states the first question as erdos_1106.parts.i with answer(True), the category research solved and a sorry body, citing this paper; it is a statement, not a proof.