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High-order Accurate Inference on Manifolds

Chengzhu Huang, Anru R. Zhang

TL;DR

The paper develops a framework for high-order statistical inference on Riemannian manifolds by integrating bootstrap methods with Riemannian Newton iterations and curvature-aware coordinate schemes. It uses fixed normal charts, second-order retracts, and double exponential mappings to achieve accurate hypothesis tests and confidence regions for manifold-valued parameters, with explicit distributional guarantees via Edgeworth-type analyses. The methodology is demonstrated across sphere, Stiefel, fixed-rank matrices, and rank-one tensor manifolds, including Gaussian location and barycenter applications, supported by simulation studies. This work enables reliable, high-precision uncertainty quantification in non-Euclidean parameter spaces common in modern data analysis, while highlighting the role of curvature and chart choice in inference.

Abstract

We present a new framework for statistical inference on Riemannian manifolds that achieves high-order accuracy, addressing the challenges posed by non-Euclidean parameter spaces frequently encountered in modern data science. Our approach leverages a novel and computationally efficient procedure to reach higher-order asymptotic precision. In particular, we develop a bootstrap algorithm on Riemannian manifolds that is both computationally efficient and accurate for hypothesis testing and confidence region construction. Although locational hypothesis testing can be reformulated as a standard Euclidean problem, constructing high-order accurate confidence regions necessitates careful treatment of manifold geometry. To this end, we establish high-order asymptotics under a fixed normal chart centered at the true parameter, thereby enabling precise expansions that incorporate curvature effects. We demonstrate the versatility of this framework across various manifold settings-including spheres, the Stiefel manifold, fixed-rank matrices manifolds, and rank-one tensor manifolds-and, for Euclidean submanifolds, introduce a class of projection-like coordinate charts with strong consistency properties. Finally, numerical studies confirm the practical merits of the proposed procedure.

High-order Accurate Inference on Manifolds

TL;DR

The paper develops a framework for high-order statistical inference on Riemannian manifolds by integrating bootstrap methods with Riemannian Newton iterations and curvature-aware coordinate schemes. It uses fixed normal charts, second-order retracts, and double exponential mappings to achieve accurate hypothesis tests and confidence regions for manifold-valued parameters, with explicit distributional guarantees via Edgeworth-type analyses. The methodology is demonstrated across sphere, Stiefel, fixed-rank matrices, and rank-one tensor manifolds, including Gaussian location and barycenter applications, supported by simulation studies. This work enables reliable, high-precision uncertainty quantification in non-Euclidean parameter spaces common in modern data analysis, while highlighting the role of curvature and chart choice in inference.

Abstract

We present a new framework for statistical inference on Riemannian manifolds that achieves high-order accuracy, addressing the challenges posed by non-Euclidean parameter spaces frequently encountered in modern data science. Our approach leverages a novel and computationally efficient procedure to reach higher-order asymptotic precision. In particular, we develop a bootstrap algorithm on Riemannian manifolds that is both computationally efficient and accurate for hypothesis testing and confidence region construction. Although locational hypothesis testing can be reformulated as a standard Euclidean problem, constructing high-order accurate confidence regions necessitates careful treatment of manifold geometry. To this end, we establish high-order asymptotics under a fixed normal chart centered at the true parameter, thereby enabling precise expansions that incorporate curvature effects. We demonstrate the versatility of this framework across various manifold settings-including spheres, the Stiefel manifold, fixed-rank matrices manifolds, and rank-one tensor manifolds-and, for Euclidean submanifolds, introduce a class of projection-like coordinate charts with strong consistency properties. Finally, numerical studies confirm the practical merits of the proposed procedure.
Paper Structure (70 sections, 19 theorems, 205 equations, 6 figures, 2 tables, 5 algorithms)

This paper contains 70 sections, 19 theorems, 205 equations, 6 figures, 2 tables, 5 algorithms.

Key Result

Proposition 1

Suppose the following assumptions hold: If $\theta_0 = \theta_1$, then it holds for every $\xi \in (0,\frac{1}{2}]$ that where $z^*_{T_{\phi,j},k, \alpha}$ is defined as a value that minimizes $|\mathbb{P}[T_{\phi,j}^* \leq z |\mathcal{X}_n] - (1- \alpha) |$ over $z\in \mathbb{R}$ and $z^*_{W_\phi,2,\alpha}$ is defined analogously.

Figures (6)

  • Figure 1: A Counterexample: Irregular Empirical Distribution Using an Irregular Chart. We consider the fixed-rank matrices manifold with the sample size $n = 1000$ and the ground truth parameter $\boldsymbol \theta_0 = \textrm{diag}(1,1,0,0)$. The histogram represents the studentized version of $(R_{\widehat{\theta}_n}^{-1}(\theta_0))_1$ while the blue curve depicts the probability density function of the standard normal distribution.
  • Figure 2: Tangent spaces and coordinates of a dimension-$2$ submanifold $\mathcal{M}$ in $\mathbb{R}^3$.
  • Figure 3: Double exponential mapping
  • Figure 4: Scaled Cumulative Distribution Function Difference. column $1$: Stiefel Manifold; column $2$: fixed-rank matrices manifold; column $3$: Rank-One Tensor Manifold; row $1$: log-scaled Wald Statistic; row $2$: $\sqrt{n}$-scaled Wald Statistic; row $3$: log-scaled intrinsic $t$-Statistic; row $4$: $\sqrt{n}$-scaled intrinsic $t$-Statistic; Black: resampled statistic (our method); Red: non-studentized resampled statistic; Blue: chi-square distribution / standard normal distribution.
  • Figure 5: Scaled Cumulative Distribution Function Difference for Extrinsic $t$-statistic for fixed-rank matrices manifold. Black: the empirical distribution of the resampled statistic; Red: the empirical distribution of the non-studentized resampled statistic; Blue: the distribution of the standard normal distribution.
  • ...and 1 more figures

Theorems & Definitions (40)

  • Definition 1
  • Remark 1
  • Remark 2
  • Proposition 1
  • Theorem 1: Convergence guarantees: Algorithm \ref{['algorithm: update']} with full data
  • Theorem 2: Convergence guarantees: Algorithm \ref{['algorithm: update']} with bootstrapped data
  • Remark 3
  • Remark 4
  • Theorem 3
  • Proposition 2
  • ...and 30 more