Unsolved

Valid Uncertainty Quantification for Extremal Graph Structure

Sourced from the work of Sebastian Engelke, Michael Lalancette, Stanislav Volgushev

§ Problem Statement

Setup

Engelke, Lalancette, and Volgushev (Annals of Statistics, 2025) explicitly identify uncertainty quantification for estimated extremal graphs as an important future direction, beyond graph recovery. The source does not itself state a fully formal high-dimensional simultaneous-inference theorem with explicit uniform size/coverage or FWER/FDR formulas.

This setup follows Engelke et al. (2025).

Unsolved Problem

Let d=dnd=d_n and let Y(1),,Y(n)Y^{(1)},\dots,Y^{(n)} be i.i.d. observations from a dd-variate H"usler--Reiss multivariate Pareto model on E={y[0,)d:max1rdyr>1}E=\{y\in[0,\infty)^d:\max_{1\le r\le d}y_r>1\} with variogram matrix Γ=(Γrs)1r,sd\Gamma=(\Gamma_{rs})_{1\le r,s\le d}. Assume Γ\Gamma is symmetric, Γrr=0\Gamma_{rr}=0, and strictly conditionally negative definite (equivalently: negative definite on {xRd:rxr=0, x0}\{x\in\mathbb R^d:\sum_r x_r=0,\ x\neq 0\}), so that for anchor m=dm=d the matrix

Σij=12(Γid+ΓjdΓij),i,j{1,,d1},\Sigma_{ij}=\frac{1}{2}\big(\Gamma_{id}+\Gamma_{jd}-\Gamma_{ij}\big),\qquad i,j\in\{1,\dots,d-1\},

is positive definite and hence Θ=Σ1\Theta=\Sigma^{-1} is well-defined. In this model class, the extremal graph on vertices {1,,d1}\{1,\dots,d-1\} has edge {i,j}\{i,j\} iff Θij0\Theta_{ij}\neq 0 for iji\neq j.

Open problem: construct edge-wise and simultaneous inferential procedures for off-diagonal entries of Θ\Theta that remain valid when both nn\to\infty and d=dnd=d_n\to\infty. For each pair iji\neq j, target tests of

H0ij:Θij=0versusH1ij:Θij0,H_0^{ij}:\Theta_{ij}=0 \quad\text{versus}\quad H_1^{ij}:\Theta_{ij}\neq 0,

and (1α)(1-\alpha) confidence intervals CijC_{ij} with high-dimensional uniform guarantees over suitable classes (e.g., bounded spectrum, sparsity, and admissible growth):

supPPnij,0PrP(reject H0ij)α0,supPPnPrP(ΘijCij)(1α)0.\sup_{P\in\mathcal P_n^{ij,0}}\big|\Pr_P(\text{reject }H_0^{ij})-\alpha\big|\to 0,\qquad \sup_{P\in\mathcal P_n}\big|\Pr_P(\Theta_{ij}\in C_{ij})-(1-\alpha)\big|\to 0.

Also target simultaneous error criteria such as asymptotic FWER/FDR control, e.g. PrP(V1)α+o(1)\Pr_P(V\ge 1)\le \alpha+o(1) or EP[V/max{R,1}]q+o(1)\mathbb E_P[V/\max\{R,1\}]\le q+o(1).

§ Discussion

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§ Significance & Implications

The source paper establishes the need for uncertainty quantification in extremal graphical models. Since 2021, related inference developments (including H"usler--Reiss matrix-completion and likelihood-based uncertainty-quantification work in lower- or moderate-dimensional regimes) have improved the toolkit, but they do not yet close the core high-dimensional-uniform inference gap for edge-wise and simultaneous graph uncertainty.

§ Known Partial Results

  • Engelke et al. (2025): Partially resolved outside the strict open scope: existing results provide concentration guarantees and graph-recovery consistency, and newer post-2021 work gives additional inference machinery in more restricted settings. Still open in the stated sense: high-dimensional, uniform-valid edge-wise and simultaneous inference guarantees for extremal graph structure.

§ References

[1]

Learning extremal graphical structures in high dimensions

Sebastian Engelke, Michael Lalancette, Stanislav Volgushev (2025)

Annals of Statistics

📍 Section 7 (Extensions and future work) in the published Annals version, paragraph beginning "Another highly promising direction for future research is uncertainty quantification for the estimated graph..."

Published source paper; the uncertainty-quantification direction is discussed as future work.

§ Tags