Cyclicity-index conjecture for imaginary quadratic class groups

Fix nNn\in\mathbb{N} and a partition λ=(n1,,nr)\lambda=(n_1,\dots,n_r) of nn, with n1nr1n_1\geq\cdots\geq n_r\geq1, and define

Gλ(p)=i=1rZ/pniZ,c(λ)=i=1r(32i)ni.G_\lambda(p)=\bigoplus_{i=1}^r\mathbb{Z}/p^{n_i}\mathbb{Z},\qquad \operatorname{c}(\lambda)=\sum_{i=1}^r(3-2i)n_i.

For a finite abelian group GG, let F(G)\mathcal{F}(G) denote the number of negative fundamental discriminants whose imaginary quadratic class group is isomorphic to GG. Cyclicity-index conjecture. The inequality F(Gλ(p))>0\mathcal{F}(G_\lambda(p))>0 holds for infinitely many primes pp if and only if c(λ)0\operatorname{c}(\lambda)\geq0. If c(λ)>0\operatorname{c}(\lambda)>0, then

F(Gλ(p))Cnpc(λ)logp\mathcal{F}(G_\lambda(p))\sim\frac{\mathfrak{C}}{n}\frac{p^{\operatorname{c}(\lambda)}}{\log p}

as pp\to\infty. If c(λ)=0\operatorname{c}(\lambda)=0, then

px\p primeF(Gλ(p))Cnx(logx)2.\sum_{\substack{p\leq x\p\text{ prime}}}\mathcal{F}(G_\lambda(p))\sim\frac{\mathfrak{C}}{n}\frac{x}{(\log x)^2}.

If c(λ)<0\operatorname{c}(\lambda)<0, then pλ1p\gg_\lambda1 implies F(Gλ(p))=0\mathcal{F}(G_\lambda(p))=0. This gives a precise predicted criterion for which abelian pp-group shapes occur for infinitely many primes, but the source does not specify a resolution.

Sources & referencesView supporting material

Primary source

Samuel Holmin, Nathan Jones, Pär Kurlberg, Cam McLeman and Kathleen L. Petersen, “Missing class groups and class number statistics for imaginary quadratic fields”, arXiv:1510.04387 (2015).

Progress summary

Never refreshed

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

Solutions 0

No solutions have been posted yet.