The exact asymptotic formula conjecture for Turán's problem 10

From papers

Let α>0\alpha>0 be real, and define

Fn(α)=infzkC,zk1maxν=1,,αn2k=1nzkν.F_n(\alpha)=\inf_{z_k\in\mathbb C,\,|z_k|\geq1}\max_{\nu=1,\ldots,\lfloor\alpha n^2\rfloor}\left|\sum_{k=1}^n z_k^\nu\right|.

Theorem u77u77 gives

(A(α)o(1))nFn(α)(A(α)+o(1))n,(\underline A(\alpha)-o(1))\sqrt n\leq F_n(\alpha)\leq(\overline A(\alpha)+o(1))\sqrt n,

where

A(α)={11α,0<α1,1,α>1,A(α)={1,0<α1,2,1<α2,3,2<α3,2,3<α.\underline A(\alpha)=\begin{cases}1-\sqrt{1-\alpha},&0<\alpha\leq1,\\1,&\alpha>1,\end{cases} \qquad \overline A(\alpha)=\begin{cases}1,&0<\alpha\leq1,\sqrt2,&1<\alpha\leq2,\sqrt3,&2<\alpha\leq3,\\2,&3<\alpha.\end{cases}

Exact asymptotic formula conjecture. One can choose A(α)=A(α)=A(α)A(\alpha)=\underline A(\alpha)=\overline A(\alpha) in Theorem u77u77. This would determine the true asymptotic constant for every α>0\alpha>0. The theorem establishes matching bounds only in special cases, notably α=1\alpha=1; the general problem remains open.

Progress summary

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Sources & referencesView supporting material

Primary source

Johan Andersson, “Turan's problem 10 revisited”, arXiv:math/0609271 (2007).

Solutions 0

No solutions have been posted yet.