NeurIPS 2026 Papers

Conference on Neural Information Processing Systems

Decision breakdown

6,437papers

Counted from the official paper list; may differ slightly from the number the conference announced.

  • Oral
    991.5%
  • Spotlight
    2403.7%
  • Poster
    6,09894.7%

Browse all papers

StreamOV: Streaming Omni-Video Understanding via Evidence-Guided Memory and Response Triggering

Ming Xie, Zizheng Huang, Xudong Tan, Chao Wang, Xiangyu Zeng, Wenxiao Wu, Tao Chen, Limin Wang, Yanwei Fu

Expand abstract

While streaming omni-video understanding demands continuous perception and proactive, real-time interaction, this crucial area remains largely under-explored. Current omni-modal methods are inherently designed for offline settings, limiting their applicability in streaming scenarios due to two fundamental flaws. First, they lack robust mechanisms to manage continuously growing audio-visual context over long horizons and cannot autonomously initiate responses at opportune moments. Second, existing benchmarks are predominantly confined to offline, single-turn question answering, failing to capture continuous, multi-turn streaming interactions. To bridge these gaps, we propose StreamOV, a novel Streaming Omni-Video understanding framework for efficient online audio-visual reasoning with bounded memory and proactive response triggering. Specifically, StreamOV introduces a multimodal evidence-guided long-short term memory that condenses historical audio-visual context into compact informative evidence under a fixed budget. It further employs a hidden-state-driven trigger to decide when to respond, avoiding explicit silence-token generation and external routers. We also curate SOVBench, the first comprehensive benchmark for online, multi-turn omni-modal evaluation. Extensive experiments show that StreamOV achieves state-of-the-art performance across diverse streaming and omni-video benchmarks, demonstrating its effectiveness for both online and offline video understanding.

Poster
StreamGaze: Gaze-Guided Temporal Reasoning and Proactive Understanding in Streaming Videos

Daeun Lee, Subhojyoti Mukherjee, Branislav Kveton, Ryan Rossi, Viet Lai, David Seunghyun Yoon, Trung Bui, Franck Dernoncourt, Mohit Bansal

Expand abstract

Streaming video understanding requires models not only to process temporally incoming frames, but also to anticipate user intention for realistic applications such as Augmented Reality (AR) glasses. While prior streaming benchmarks evaluate temporal reasoning, none measure whether Multimodal Large Language Models (MLLMs) can interpret or leverage human gaze signals within a streaming setting. To fill this gap, we introduce StreamGaze, the first benchmark designed to evaluate how effectively MLLMs utilize gaze for temporal and proactive reasoning in streaming videos. StreamGaze introduces gaze-guided past, present, and proactive tasks that comprehensively assess streaming video understanding. These tasks evaluate whether models can use real-time gaze signals to follow shifting attention and infer user intentions based only on past and currently observed frames. To build StreamGaze, we develop a gaze–video Question Answering (QA) generation pipeline that aligns egocentric videos with raw gaze trajectories through fixation extraction, region-specific visual prompting, and scanpath construction. This pipeline produces spatio-temporally grounded QA pairs that reflect human perceptual dynamics. Across all StreamGaze tasks, we observe substantial performance gaps between state-of-the-art MLLMs and human performance, highlighting key limitations in gaze-based temporal reasoning, intention modeling, and proactive prediction. We further provide detailed analyses of gaze prompting strategies, reasoning behaviors, and task-specific failure modes, offering insights into current limitations and directions for future research. All data and code are publicly available to support research in gaze-guided streaming video understanding.

Poster
Strategist: Designing Agentic Reasoning at Scale

TaiMing Lu, Qi Xu, Zhigang Hua, Zhuang Liu

Expand abstract

In practice, the reasoning strategy often matters more than the model. Rather than calling a fixed large model once per input, a well-designed strategy breaks the problem into steps and uses the right model for each, achieving better accuracy at lower cost. Existing methods have tried to automate strategy design by searching over a fixed set of strategy templates, but the templates themselves limit what reasoning patterns can be discovered. We propose Strategist, a meta-agent that designs a high-performing inference strategy for a given task. Each strategy is a structured executable topology that defines how agents plan, interact, verify, and route across models. Given a task and a small development set, Strategist proposes candidate strategies, runs them on real samples, and revises them against measured accuracy and cost. Every strategy and its components are reusable, forming an evolving library that grows with each new task and compounds what future tasks can build from. On 30 benchmarks, Strategist matches or beats the strongest baselines with an average of 8.5 absolute percentage points higher accuracy at 48% lower inference cost.

Poster
Strategic Feature Selection and Regularization

Jivat Neet Kaur, Pratik Patil, Divya Shanmugam, Emma Pierson, Michael Jordan, Nika Haghtalab, Meena Jagadeesan, Ahmed Alaa, Serena Wang

Expand abstract

When algorithmic predictors inform resource allocation in high-stakes domains such as healthcare, these predictors must account for strategic manipulation of input features. The typical solution is to redesign the predictor itself to explicitly account for strategic interactions. In practice, however, decision makers are often constrained to adjusting coarser levers within existing prediction pipelines. For example, healthcare organizations often select which features to exclude based on perceived manipulability, while using standard regularization procedures to shrink the coefficients of retained features. In this work, we initiate a formal study of strategic classification through *feature selection* and its interaction with *ridge regularization*. Our main finding is that excluding features based on manipulability alone is generally suboptimal. We provide a fine-grained characterization of the performance of a feature subset under optimal regularization, yielding new insights for policy design. Motivated by this characterization, we develop a practical algorithm for jointly choosing the feature set and the level of ridge regularization. Through a real-world case study on a healthcare payments benchmark, we illustrate how our algorithm can guide the design of coarse policy levers in practice. Our results provide a principled, practical framework for mitigating the effects of strategic behavior in algorithmic decision-making systems.

Poster
Strategic Evaluation: Incentivizing AI Capability Coverage with Private Benchmarks

Sang Truong, Serena Wang, Nick Haber, Sanmi Koyejo

Expand abstract

Public benchmarks play a significant role in steering LLM development, as market incentives drive model developers to optimize for leaderboard performance. However, fundamental information limitations mean that evaluators are only able to cover a subset of socially relevant capabilities with their evaluation tasks. On the other hand, model developers often have additional private benchmarks that are unavailable to evaluators. The resulting information asymmetry opens the door to strategic task specialization that can lead to suboptimal social welfare. We propose randomized evaluation mechanisms (effectively private benchmarks) as a way to incentivize model developers to train to cover a broader set of socially relevant tasks, including those unknown to the evaluator. We formalize this as a dynamic game with information asymmetry between an evaluator and a model developer. We prove that randomized evaluation aligns incentives to the developer’s prior belief over possible evaluated tasks, and is socially optimal when that belief matches society, but information leakage degrades this over rounds. However, if the evaluator can continually update their known task set, alignment can be asymptotically recovered. We illustrate a variance–leakage–correction tradeoff in semisynthetic experiment with a latent factor structure over MMLU-Pro.

Poster
Strategic Decision Focused Learning

Tinashe Handina, Yuehan Lucy Diao, Adam Wierman, Eric Mazumdar

Expand abstract

Machine learning (ML) predictions are increasingly being used to guide decision-making, giving rise to the problem of decision-focused learning (DFL) where predictors are optimized for downstream decision quality rather than accuracy alone. However, existing work assumes a single decision-maker optimizing in isolation. This paper formalizes *strategic* decision-focused learning, where an ML system predicts an exogenous state that some agents observe before playing a game. For example, a park ranger may predict wildlife locations to allocate anti-poaching patrols against strategic poachers. While the exogenous state is unaffected by agent actions, predictions influence agents' strategies and the resulting equilibrium. We find that strategic considerations fundamentally change the learning problem. In particular, we show the prediction accuracy–equilibrium payoff landscape can be non-monotonic---i.e., better predictions can degrade performance. We propose algorithmic approaches to address these challenges and validate them across benchmarks in wildlife conservation and infrastructure protection. Our theory and experiments highlight the importance of accounting for strategic interactions when designing predictors.

Poster
Strategic Causal Policy Learning: Welfare, Safety, and Fairness Thresholds

Suhwan Bong

Expand abstract

The standard rule in unconstrained causal policy learning is simple: treat individuals with nonnegative CATE. We show that this rule can fail when treatment eligibility is strategically manipulable. Agents may move or report covariates after a policy is announced, so treatment is assigned using manipulated covariates while welfare remains determined by baseline CATEs. This creates a mismatch between who receives treatment and who benefits from treatment. We formalize this setting as strategic causal policy learning and show that strategic welfare equals the CATE-weighted mass of baseline types that can reach the treatment region. This access-burden representation leads to three distinct strategic thresholds: a welfare threshold, a safe threshold, and a fair threshold. For linear CATE models, we derive closed-form threshold corrections. Homogeneous costs admit a single buffer correction that recovers the ideal positive-CATE allocation, while heterogeneous costs make welfare maximization, no-exploit safety, and subgroup fairness select different policies. Experiments illustrate these tradeoffs and show when group-specific corrections can restore the ideal allocation.

Poster
Stranger Things: When Objects Appear Without Their Typical Neighbours

Siddhartha Gairola, Jiahao Xie, Anna Kukleva, Francesco Locatello, Bernt Schiele

Expand abstract

Visual context is a powerful cue for object recognition: scenes inform what, where, and at what scale objects are likely to appear. Yet over-reliance on context becomes a failure mode when models predict objects based on their typical neighbours rather than the objects' own visual features, a phenomenon we refer to as typicality bias. While this issue has been extensively studied in the pre-Transformer era, it has often been assumed that architectural and scale improvements would naturally solve it. Despite recent attempts in isolated settings, a systematic diagnostic across the modern vision stack remains absent. In this work, we provide such a diagnostic framework. Specifically, we measure typicality bias via normalized pointwise mutual information (NPMI) over object pairs, and introduce STRANGE-Bench (Synthetic Typicality-RANked Grounded Evaluation Benchmark): a photorealistic, layout-controlled benchmark spanning 11 typicality tiers from typical to never-co-occurring object pairs. Across \five model families (specialist detectors, open-vocabulary detectors, self-supervised, vision-language, and multimodal large language models) and three recognition tasks}(supervised detection, open-vocabulary detection, and classification), we find the bias to be highly prevalent: gaps of 5--11\% persist when objects appear outside their typical company, and they do not consistently shrink with scale. This persistence motivates a complementary question: how to mitigate it? Data augmentation is a natural lever, since it directly shapes the training distribution that produces the bias; yet existing augmentations are designed for visual diversity, not for breaking co-occurrence shortcuts as they sample from the very distribution that produces typicality bias, preserving rather than perturbing it. We therefore propose Anchor-Atypicality Sampling (AAS), a simple context-aware variant of paste-based augmentations that uses the NPMI signal to deliberately tilt the training-time co-occurrence distribution toward atypical partners. AAS reduces the typicality gap by up to 3.3 pp on natural-image COCO splits and 17.4 pp on synthetic STRANGE-Bench across three representative model families (specialist detection, open-vocabulary detection, self-supervised classification), without sacrificing overall performance.

Poster
StraTA: Incentivizing Agentic Reinforcement Learning with Strategic Trajectory Abstraction

Xiangyuan Xue, Yifan Zhou, Zidong Wang, Shengji Tang, Philip Torr, Wanli Ouyang, Lei Bai, Zhenfei Yin

Expand abstract

Large language models (LLMs) are increasingly used as interactive agents, but optimizing them for long-horizon decision making remains difficult because current methods are largely purely reactive, which weakens both exploration and credit assignment over extended trajectories. In this work, we present Strategic Trajectory Abstraction (StraTA), a simple framework that introduces an explicit trajectory-level strategy into agentic reinforcement learning (RL). StraTA samples a compact strategy from the initial task state, conditions subsequent actions on that strategy, and trains strategy generation and action execution jointly with a hierarchical GRPO-style rollout design, further enhanced by diverse strategy rollout and critical self-judgment. Experiments on ALFWorld, WebShop, and SciWorld show that StraTA consistently improves both sample efficiency and final performance over strong baselines. StraTA reaches success rates of 93.1% on ALFWorld and 84.2% on WebShop, surpassing the strongest baselines by 2.3% and 11.4% respectively. On SciWorld, StraTA attains a 63.5% overall score, outperforming frontier closed-source models by 6.1% and prior RL baselines by 6.5%.

Poster
Stop the Sampler! Classifier-Based Adaptive Stopping for Sampling Kernels

Kirill Korolev, Nikita Morozov, Stepan Pavlenko, Esmeralda S. Whitammer, Sergey Samsonov

Expand abstract

Sampling from complex, unnormalized probability densities is a fundamental challenge in Bayesian inference and probabilistic modeling. While Markov chain Monte Carlo (MCMC) methods provide asymptotic guarantees, they often suffer from slow mixing and high computational costs due to fixed or manually tuned trajectory lengths. In this work, we propose a novel framework that treats trajectory termination as a learnable component of the sampling dynamics. By framing MCMC within the theory of non-acyclic Generative Flow Networks (GFlowNets), we train state-dependent neural classifiers to decide when a trajectory has reached a high-density region and should terminate. We theoretically establish the connection between optimal classifiers and the target density via detailed balance conditions and introduce a multilevel training scheme to facilitate exploration in complex geometries. Experimental results across various benchmark densities demonstrate that our approach significantly reduces average trajectory lengths while improving mode coverage and mixing compared to standard MCMC baselines.

Poster
Stop or Restart? Principled Inference Control for Large Reasoning Models via the Pandora's Box

Xiaosong Yuan, Xiaofeng Zhang, Yijia Zhang, Renchu Guan, Ying Wang

Expand abstract

While large reasoning models (LRMs) can solve complex tasks via generating extended Chain-of-Thought traces (Long-CoT), longer traces often increase confidence without increasing correctness. In this work, we formalize such failure via a \emph{self-conditioned evidence} model: generated tokens provide information about the model's current working hypothesis rather than the ground-truth answer. This yields a simple diagnostic principle: entropy, fluency, and answer stability can certify within-trajectory self-consistency while remaining causally disconnected from correctness. Building on these findings, we propose \textbf{Faithful Pandora Inference (FPI)}, a minimal training-free controller that keeps the base LRM frozen and fits only a small calibration map on held-out data. At each checkpoint, FPI estimates calibrated correctness $r_t$ and the marginal evidence gain $m_t$ of continuing the current trajectory. It stops only when $r_t$ reaches a user-specified reliability target; if $r_t$ remains insufficient and $m_t$ falls below cost, it reallocates the remaining budget to a diversified restart. Across six reasoning benchmarks and multiple DeepSeek-R1 distilled models, FPI improves the accuracy-efficiency frontier, reduces expected calibration error, and improves selective accuracy on high-confidence outputs. Ablations on confidently wrong trajectories show that calibrated stopping and marginal-gain restarts address different failure modes and that the gains are not explained by additional samples alone.

Poster
Stop Quantum Machine Learning; do AI-for-Quantum instead

ziqing Guo, Ziwen Pan

Expand abstract

This paper argues that the NeurIPS community should prioritize AI-for-Quantum (AI4Q) over Quantum Machine Learning (QML) on classical data, and should review the two directions by different evidentiary standards. We argue that QML on classical data has not earned high priority because its leading advantage claims rely on strong input assumptions, face trainability and noise barriers, and still lacks persuasive wall-clock wins on the standard benchmarks. By contrast, AI4Q has already produced concrete gains in decoding, compilation, neural-state representation, tomography and readout, and error mitigation. We make the evidentiary standard explicit through falsification criteria and concrete review-process recommendations.

Poster
StomataBench: Measuring Taxonomic Generalization in Stomatal Detection

Sainath Reddy Gummi, Hankui K. Zhang, Chulwoo Pack, Shyam Solanki, Young Chang

Expand abstract

Accelerating stomata measurement is essential for developing drought-resilient plants. However, most automated stomata detectors are tested under narrow imaging and species conditions. Their behavior under broader ecological distribution shift remains unclear. We introduce StomataBench, a benchmark for stomatal object detection across species, acquisition protocols, and biological density regimes. The benchmark uses a curated multispecies training set of 3,154 images with 134,802 annotated stomata from 21 woody species. It is evaluated on four test datasets totaling 19,657 images, covering diverse woody taxa and heterogeneous public crop sources. Unlike standard detection benchmarks that report only AP, StomataBench evaluates measurement reliability. We measure COCO AP, F1, score-threshold sensitivity, image-level count error, and stomatal density agreement. We benchmark sixteen detectors spanning two-stage, one-stage, transformer, open-vocabulary, and promptable foundation models. The results show that model rankings change with the biological objective. GDINO-SB provides the strongest average AP generalization, while SAM3-OD gives reliable operating point for count and density estimation. Conventional detectors remain competitive on near-domain woody plants, but foundation models are robust under harder ecological shifts. Failure analysis shows that far-OOD detection is often limited by missing stomata. These results identify cross-lineage proposal generation as a key unsolved problem for reliable stomatal phenotyping under ecological distribution shift.

Spotlight
Stochastic Zeroth-Order Optimization Under Heavy-Tailed Noise

Taha EL BAKKALI EL KADI, El Mahdi Chayti, Qiuyi (Richard) Zhang, Imane Rahali, Omar Saadi

Expand abstract

We study stochastic zeroth-order (ZO) optimization of smooth nonconvex objectives under heavy-tailed sample-gradient noise, a regime motivated by empirical evidence that gradient noise in modern machine learning can violate the bounded-variance assumption underlying classical ZO theory. While the first-order literature has established optimal rates under bounded $p$-th moment noise for $p \in (1,2]$, analogous high-probability guarantees for nonconvex ZO optimization remain largely unexplored. The ZO setting is not a direct corollary of first-order theory: first-order methods update using $\nabla F(x;\xi)$, the same object on which the noise assumption is imposed, whereas derivative-free methods only observe noisy function values and construct directional finite-difference estimates. Thus, weak-$L_p$ control of $\nabla F(x;\xi)-\nabla f(x)$ must first be transferred to scalar two-point directional estimates, a concentration step absent from standard first-order analyses. We propose the Robust Scalar-Clipped Zeroth-Order method (\textbf{RSC-ZO}), a two-point method that clips each scalar directional derivative before aggregation. Under sample-wise smoothness and a weak-$L_p$ tail bound on the sample-gradient noise, RSC-ZO finds an $\varepsilon$-stationary point with high probability using $ \widetilde{O}\\left( \frac{d^{\frac{p}{2(p-1)}}} {\varepsilon^{\frac{3p-2}{p-1}}} \right) $ noisy function evaluations, matching the optimal first-order $\varepsilon$-dependence. At $p=2$, our bound becomes $\widetilde{O}(d\varepsilon^{-4})$, matching the classical dimension-accuracy dependence for stochastic ZO methods under bounded-variance noise, which is typically established only in expectation. In contrast, our guarantee holds with high probability and under the strictly weaker weak-$L_2$ tail condition, which can allow infinite gradient-noise variance. We further extend the analysis to a momentum variant and quantify the resulting batch-size/stepsize tradeoff.

Poster
Stochastic Reconfiguration as Statistical Filtering for Overparameterized Neural Quantum States

Tak Hur

Expand abstract

Stochastic reconfiguration (SR) is the standard optimizer for neural quantum states (NQS), but modern NQS often have far more parameters than Monte Carlo samples. We show that in this regime the diagonal shift is more than a numerical stabilizer. It acts as a statistical filter for finite-sample generalization. At a fixed wave function, SR is ridge regression from tangent features to the centered local energy. Its residual is the expressivity gap, the part of imaginary-time evolution outside the current tangent space. This gap is orthogonal to the tangent space in population, but finite batches make it act as noise that SR can overfit. The shift therefore balances shrinkage of useful update directions against variance from fitting sampled residuals. Exact $4\times4$ $J_1$-$J_2$ experiments separate two effects of overparameterization. Larger tangent spaces help when they reduce the expressivity gap, but they can hurt when they overfit a fixed gap. In a $100$-site transverse-field Ising family trained with a foundation NQS, validation risk is U-shaped in the shift while variance decreases, matching the noisy-ridge model. This view leads to multi-shift SR (MS-SR), which averages independent ridge solves at data-adaptive shifts to form a richer, lower-variance spectral filter. MS-SR lowers validation risk and stays closer to the ideal tangent-space imaginary-time update compared to other competitive NQS optimizers.

Poster
Stochastic Optimization with Random Search

El Mahdi Chayti, Taha EL BAKKALI EL KADI, Omar Saadi, Martin Jaggi

Expand abstract

We study stochastic random search for nonconvex optimization with only noisy function evaluations. We propose Mi2P, a two-point variant of stochastic three-point methods, and analyze it under generalized $(L_0,L_1)$-smoothness. Two regimes are considered. When the mean objective $f$ is $(L_0,L_1)$-smooth and component variance is bounded, Mi2P achieves $\widetilde{O}(d^3\sigma_0^2/\varepsilon^{6})$, matching the rate of \citet{boucherouite2024mistp} under a strictly weaker assumption (they require $f$ to be $L$-smooth, i.e., $L_1=0$). When an $L^1$-average $(L_0,L_1)$-smoothness holds across $\xi$, Mi2P attains the optimal $\widetilde{O}(d\sigma^2/\varepsilon^{4})$ rate; the per-sample $L$-smoothness used by gradient-estimation methods such as RSGF \citep{ghadimi2013stochastic} (i.e., each $f_\xi$ is $L$-smooth, $L_1 = 0$ pointwise in $\xi$) is a special case of this condition. For finite sums with $G$-Lipschitz components, a translation-symmetric variance-reduction scheme yields $\widetilde{O}(\min\{d^{4/3}n^{2/3}/\varepsilon^{8/3},\, dn/\varepsilon^2\})$ without storing snapshots. We also extend the framework to $\delta$-inexact comparison feedback (e.g., RLHF, A/B testing), giving an $O(\sqrt{d\delta})$ accuracy floor. Our analysis is presented for directional distributions with bounded support; the same rates hold for any rotation-invariant distribution with sub-Gaussian tails on the norm of $s$ (including Gaussian) under a step-size restriction that does not affect the asymptotic complexity.

Poster
Stochastic Interpolants via Conditional Dependent Coupling

Chenrui Ma, Xi Xiao, Tianyang Wang, Xiao Wang, Yanning Shen

Expand abstract

Existing image generation models face critical challenges regarding the trade-off between computation and fidelity. Specifically, models relying on a pretrained Variational Autoencoder (VAE) suffer from information loss, limited detail, and the inability to support end-to-end training. In contrast, models operating directly in the pixel space incur prohibitive computational cost. Although cascade models can mitigate computational cost, stage-wise separation prevents effective end-to-end optimization, hampers knowledge sharing, and often results in inaccurate distribution learning within each stage. To address these challenges, we introduce a unified multi-stage generative framework formulated under the \emph{stochastic interpolant} formalism with our \textbf{Conditional Dependent Coupling} strategy as a Flow-Matching variant. It decomposes the generative process into interpolant trajectories at multiple stages, ensuring accurate distribution learning while enabling end-to-end optimization. Importantly, the entire process is modeled as a single unified Diffusion Transformer, eliminating the need for disjoint modules and also enabling knowledge sharing. Under explicitly stated assumptions, we provably reduce both transport cost and asymptotic inference time, we empirically validate the underlying NFE--transport-cost and per-evaluation-cost relations. Extensive experiments demonstrate that our method achieves competitive fidelity and substantially lower wall-clock cost in the low-NFE regime across multiple resolutions.

Poster
Stochastic Heat Diffusion Models

Marc Law, Xiaoyu Wang, Lucas Berry, Anthony L. Caterini, Gabriel Loaiza-Ganem *

Expand abstract

This work introduces a family of generative diffusion models based on the stochastic heat equation. The deterministic heat equation has natural connections with kernels over discrete structures and has been successfully applied in machine learning to discriminative tasks for various types of data such as graphs. We extend it to a stochastic version by formulating our diffusion as a Gaussian process whose transition kernel can be written in closed form for both the forward- and reverse-time processes. Our diffusion process propagates noise smoothly among neighbours under the guidance of a Laplacian matrix that describes the global structure of the input. Following a flow matching-based approach, we train a denoising neural network that takes noisy representations as input and gradually removes noise to generate clean samples. We experimentally show that, by exploiting the Laplacian during training, our decoder is able to recover the global structure of the input.

Poster
Stochastic Grouping Conformal Prediction for Effective Subgroup Reliability

Meihui Zhong, Wenxin Tai, Ting Zhong, Fan Zhou

Expand abstract

Conformal prediction offers a distribution-free coverage guarantee, making it especially attractive for clinical applications. Standard conformal prediction, however, provides such guarantees only at the population level, and its prediction sets can exhibit coverage disparities across clinically important subgroups. A natural remedy is to calibrate within predefined groups. However, this can require access to sensitive subgroup attributes and is prone to a worst-group bottleneck: protecting the most difficult subgroup can inflate prediction sets for all, increasing cognitive burden on decision makers. To this end, we propose Stochastic Grouping Conformal Prediction (SGCP), a conformal framework for subgroup-reliable uncertainty quantification. It learns a stochastic grouping map that allows each sample to draw calibration information from others with similar calibration behavior, yielding a local score law that boosts reliability across subpopulations. We prove that SGCP retains the standard coverage guarantee. Experiments on synthetic and real-world benchmarks show that it consistently reduces subgroup coverage gaps while achieving smaller or comparable prediction set sizes relative to existing baselines.

Poster
Stochastic Dynamic Barrier Perturbed Gradient Methods for Nonconvex Simple Bilevel Optimization

Mohammad Mahdi Ahmadi, Jincheng Cao, Aryan Mokhtari, Erfan Yazdandoost Hamedani

Expand abstract

We study stochastic simple bilevel optimization with smooth, possibly nonconvex upper- and lower-level objectives accessed only through stochastic gradient oracles. A key challenge is that the dual multiplier induced by the lower-level constraint may become unbounded near lower-level stationary points, invalidating bounded-dual analyses and destabilizing stochastic gradient estimates. To address this, we propose \emph{Stochastic Dynamic Barrier Perturbed Gradient} (SDBPG), a single-loop method that adaptively perturbs the dual formulation to regularize this degeneracy. The perturbation stabilizes the multiplier and yields controlled bias and variance even near the lower-level stationarity region. Under a mild rare-visit assumption, SDBPG finds an $(\epsilon_f,\epsilon_g)$-stationary point in $\mathcal{O}(\max\{\epsilon_f^{-2},\epsilon_g^{-2}\})$ iterations, with sample gradient complexities $\mathcal{O}(\epsilon^{-4})$ and $\mathcal{O}(\epsilon^{-6})$ for the upper- and lower-level objectives where $\epsilon=\max(\epsilon_f,\epsilon_g)$. We further develop PR-SDBPG, a penalty-regularized variant that eliminates the rare-visit assumption, and VR-PR-SDBPG, which improves the resulting sample complexities entirely through variance reduction. To our knowledge, these are the first explicit $(\epsilon_f,\epsilon_g)$-stationarity guarantees for stochastic nonconvex-nonconvex simple bilevel optimization.

Poster