LRS asymptotic formula for rational points on multiple conics

About 1 year old · traced to

Let XX be a smooth, projective, geometrically integral, weak Fano variety over Q\mathbb{Q}. Let U⊆XU \subseteq X be an open subset and let B⊆Br⁡U\mathscr{B} \subseteq \operatorname{Br} U be a finite subset. Assume that Br⁡X=Br⁡1X\operatorname{Br} X = \operatorname{Br}_1 X, that U(Q)B≠∅U(\mathbb{Q})_{\mathscr{B}} \neq \varnothing, and that either rk⁡(Pic⁡X)=1\operatorname{rk}(\operatorname{Pic} X) = 1 or Q[U]×=Q×\mathbb{Q}[U]^\times = \mathbb{Q}^\times. LRS conjecture. There exists a thin subset Ω⊂X(Q)\Omega \subset X(\mathbb{Q}) such that

#{x∈U(Q)B:H(x)≤B,x∉Ω}∼cLRSB(log⁡B)rk⁡(Pic⁡X)−Δ(B)−1,\#\{ x \in U(\mathbb{Q})_{\mathscr{B}}: H(x) \leq B, x \notin \Omega \} \sim c_{\textup{LRS}} B(\log B)^{\operatorname{rk}(\operatorname{Pic} X) - \Delta(\mathscr{B}) - 1},

where

Δ(B)=∑D∈X(1)(1−∣∂D(⟨B⟩)∣−1),\Delta(\mathscr{B}) = \sum_{D \in X^{(1)}} \left(1 - \lvert\partial_D(\langle\mathscr{B}\rangle)\rvert^{-1}\right), cLRS=θ(X)⋅∣Br⁡Sub(X,B)/Br⁡Q∣⋅τB(X(AQ)BBr⁡Sub(X,B))Γ(X,B)⋅∏D∈X(1)η(D)1−∣∂D(⟨B⟩)∣−1,c_{\textup{LRS}} = \frac{\theta(X) \cdot \lvert\operatorname{Br}_{\mathrm{Sub}}(X,\mathscr{B})/\operatorname{Br} \mathbb{Q}\rvert \cdot \tau_{\mathscr{B}}\left(X(\mathbb{A}_{\mathbb{Q}})_{\mathscr{B}}^{\operatorname{Br}_{\mathrm{Sub}}(X,\mathscr{B})}\right)}{\Gamma(X,\mathscr{B})} \cdot \prod_{D \in X^{(1)}} \eta(D)^{1-\lvert\partial_D(\langle\mathscr{B}\rangle)\rvert^{-1}},

and

Γ(X,B)={∏D∈X(1)Γ(∣∂D(⟨B⟩)∣−1)if rk⁡(Pic⁡X)=1,Γ(rk⁡(Pic⁡X)−Δ(B))if Q[U]×=Q×.\Gamma(X,\mathscr{B}) = \begin{cases} \displaystyle \prod_{D \in X^{(1)}}\Gamma(\lvert\partial_D(\langle\mathscr{B}\rangle)\rvert^{-1}) & \text{if } \operatorname{rk}(\operatorname{Pic} X) = 1, \\ \displaystyle \Gamma\left(\operatorname{rk}(\operatorname{Pic} X) - \Delta(\mathscr{B})\right) & \text{if } \mathbb{Q}[U]^\times = \mathbb{Q}^\times. \end{cases}

This is an expected Manin-type asymptotic for rational points satisfying the Brauer conditions on weak Fano varieties. The supplied text does not establish the assertion or provide evidence resolving its status.

References

Primary source

Stephanie Chan, Peter Koymans and Nick Rome, “Serre's problem for multiple conics”, arXiv:2504.21792 (2025).

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.