NeurIPS 2026 Papers

As machine learning systems are increasingly deployed in real-world applications, the question of how to represent and quantify uncertainty has moved from a methodological side issue to a central concern. In practice, however, making a model uncertainty-aware is still surprisingly difficult: relevant tools tend to be scattered across libraries, each tied to a particular framework and a particular approach to modeling uncertainty, and the choice of representation, quantification, and evaluation is typically left to the user without much guidance. In this paper, we present probly, a Python package that addresses theses issues in a single, modular framework. probly offers (i) lightweight transformations that turn existing models into uncertainty-aware ones, currently supporting PyTorch, scikit-learn, and Flax, (ii) several representations, including second-order distributions, credal sets and conformal prediction, (iii) the corresponding quantification measures, and (iv) a number of evaluation protocols, which can be combined more or less arbitrarily. Using probly, we conduct a benchmark study on three standard tasks --- selective prediction, out-of-distribution detection, and active learning. In addition, and unlike existing benchmarks, we evaluate suitable methods on first-order data, i.e., datasets for which the target itself is a distribution over outcomes. We further illustrate the flexibility of the package on a number of less standard case studies, including large language models, graph neural networks, and data streams. The package is publicly available at \url{https://anonymous.4open.science/r/probly}.

Detailed image captioning is usually framed as an amount problem: a model should mention more visual facts while avoiding hallucination. We argue that this framing hides a basic structure of long-form captioning: a caption is an ordered sequence, and different failures appear at different positions. We introduce a position-aware rubric representation that decomposes dense human references into atomic visual claims, verifies generated captions against those claims, and induces a quartile-wise composition of supported, hallucinated, and generic content. This lens reveals two qualitatively different failures in long captions: models tend to produce unsupported specificity in the middle, while the final portion often escapes into vague, non-evidential language rather than simply accumulating more hallucination. Dense human references do not exhibit the same position-dependent pattern under the identical pipeline, suggesting that the effect is a model behavior rather than an artifact of long descriptive text. Motivated by this diagnosis, we propose *PAGER* (**P**osition-**A**ware **G**rounded **E**vidence **R**einforcement), a GRPO training objective with separate signals for supported fine-grained middle evidence, evidence-bearing tail continuation, claim coverage, and content-aware length control. The result is a closed loop: the same ordered claim representation identifies where long captions fail and supplies the position-specific reward needed to repair those failures. Experiments on detailed-caption benchmarks show that PAGER improves position-wise grounding and pairwise caption preference while preserving competitive global caption quality.

As machine learning becomes increasingly deployed in high-stakes scenarios, studying adversarial vulnerability of uncertainty-aware models has become a compelling necessity. In this paper, we focus on adversarial attacks that manipulate predictive uncertainty rather than model predictions. We focus on predictors that decompose uncertainty into aleatoric uncertainty (AU) and epistemic uncertainty (EU) and formalize uncertainty vulnerability as the maximum increase in AU achievable under a stealth constraint where the EU is kept below a threshold. This framing yields three complementary findings. First, we theoretically show that knowledge of the baseline EU can enlarge the attacker's feasible stealth region and increase the maximal achievable increase in AU. Second, a first-order analysis reveals that vulnerability is governed by the component of the AU gradient orthogonal to EU, enabling stealthy manipulation. Third, contrary to standard margin-based intuition, vulnerability peaks at moderate margins. Experiments across MNIST, CIFAR-10, and CIFAR-100 with standard architectures show that the proposed attack achieves non-trivial aleatoric damage while maintaining zero epistemic-stealth violation (e.g., mean AU increase of 0.0286, 0.0853, and 0.1568, respectively), whereas unconstrained uncertainty attacks violate the stealth constraint on over 90% of samples. Experiments indicate that the largest damage typically occurs in an intermediate uncertainty regime rather than at the extremes. Furthermore, consistent with our theoretical analysis, feasible attackability collapses under increasing epistemic uncertainty (e.g., mean attackability decreases from 0.0363 to 0). Overall, these results intimately connect uncertainty decomposition to adversarial geometry.

Cosine nearest-class-mean (NCM) evaluation is a widely used default for closed-set frozen-feature image classification because it is deterministic, train-free, and easy to reproduce. This convenience hides a metric assumption: raw angular geometry alone suffices for benchmark conclusions. We show that the assumption changes model-selection outcomes, not just absolute accuracies: across nine datasets and six frozen backbones, cosine-only reporting changes which backbone ranks first on 2 of 9 datasets and incurs 6.71 percentage points of regret relative to a best-evaluator oracle; on fixed DINOv2-B features, the underlying cosine-to-LDA gap reaches 37.63 points on Aircraft. Motivated by the low-variance spectral directions where class-discriminative signal often appears in such high-gap cases, we call this evaluator dependence the Spectral Decision Gap (SDG). SDG quantifies the gap between raw cosine and train-validated whitening-aware reference evaluators, flagging when cosine-only reporting changes benchmark conclusions. A leave-one-dataset predictive protocol reaches Pearson $r=0.752$ for best-whitening disagreement and incurs only 0.56pp routing regret at a 5pp threshold. This paper provides a compact audit protocol and artifact suite for detecting, predicting, and reporting when cosine prototype conclusions are reliable in this setting. Code and artifacts are available anonymously at https://anonymous.4open.science/r/sdg-ed/.

Multi-agent debate can improve reasoning, yet often fails to beat simple majority voting. Prior martingale-null theory explains such failures as debate without truth-directed signal. We develop a more complete account of when practical LLM debate succeeds: it needs both correct minority proposals and a readout that can recover them. We formalize this view through latent headroom, the gap between majority vote and proposal-oracle performance, which measures unused correct expertise in an expert society. For readout, we developLatent Verification Debate (LVD), a theory that models candidate proposals as receiving latent verified evidence before influencing final generation. For supply, we study neural-thicket expert societies, where nearby model perturbations provide heterogeneous specialists, and introduce a coverage-based construction that increases complementary proposal supply. Across matched-budget reasoning and multi-discipline benchmarks, our construction increases recoverable headroom, and controlled readout experiments show that gains arise from recovering surfaced correct minorities rather than merely adding interaction. Together, these results identify diverse proposal supply and verification-aware utilization as the two mechanisms that determine when debate helps.

Sign-aware recommender systems have recently been developed to leverage negative feedback for a deeper understanding of user preferences. However, our empirical diagnosis reveals that state-of-the-art graph-based sign-aware recommender systems are paradoxically *valence-blind*. Even though they explicitly incorporate sign information during training, they consistently fail to differentiate liked items from disliked ones at the ranking stage, frequently infiltrating top-$K$ recommendations with disliked content. Through linear probing, we show that while valence information exists in the learned embeddings, it remains inaccessible to the inner-product scoring function. This widespread failure remains entirely undetected because conventional evaluation metrics, such as Recall, HR, and NDCG, assign a uniform utility of zero to both negative and unobserved items, creating a systematic evaluation blind spot. To bridge this gap, we propose a family of signed metrics, Signed Recall, Signed HR, and Signed NDCG, that explicitly penalize the recommendation of disliked content. Systematic re-evaluation under our proposed metrics fundamentally reshapes the established performance landscape, revealing that methods ranked highly under conventional metrics often fail to protect users from disliked content. Finally, through a proof-of-concept auxiliary loss, we confirm that the proposed metrics provide actionable training signals, guiding models toward valence-aware behavior without sacrificing conventional relevance. For transparency, our source code is available at: https://anonymous.4open.science/r/signed-rec-benchmark-07E4

Existing Multimodal Large Language Models (MLLMs) suffer from increased inference costs due to the additional vision tokens introduced by image inputs. In this work, we propose Visual Consistency Learning (ViCO), a novel training algorithm that enables the model to represent images of varying semantic complexities using different numbers of vision tokens. The key idea behind our method is to employ multiple MLP connectors, each with a different image compression ratio, to downsample the vision tokens based on the semantic complexity of the image. During training, we minimize the KL divergence between the responses conditioned on different MLP connectors. At inference time, we introduce an image router, termed Visual Resolution Router (ViR), that automatically selects the appropriate compression rate for each image patch. Compared with existing dynamic high-resolution strategies, which adjust the number of visual tokens based on image resolutions, our method dynamically adapts the number of visual tokens according to semantic complexity. Experimental results demonstrate that our method can reduce the number of vision tokens by up to 50% while maintaining the model’s perception, reasoning, and OCR capabilities. We hope this work will contribute to the development of more efficient MLLMs. The code and models will be released to facilitate future research.

Speculative decoding accelerates large language model inference by using a draft model to generate candidate tokens, which are verified by the target model in a single forward pass. Verification proceeds and discards every position from the first rejection onward, yet existing draft training relies on token-level cross-entropy with a fixed per-position weighting that does not reflect this process. We introduce Verification-Aware Training (VAT), a plug-in framework that simulates verification at every training step and turns the resulting accept and reject patterns into supervision. VAT consists of two components: (i) a verification head, a lightweight jointly-trainable binary classifier that validates per-position acceptance via an explicit prediction target; (ii) verification-adaptive weighting replaces the fixed weighting schedule with weights adapted to each sample's first rejection point during training. VAT is model-agnostic and can be layered on top of existing methods without changing the draft architecture, the target model, or the inference procedure, and trained jointly with the original loss. Applied to EAGLE-3 and DFlash on Qwen3-4B, Qwen3-8B and LLaMA3.1-8B, VAT improves average acceptance length by up to 11.4% and wall-clock speedup by up to 8.7%, with consistent gains across math, code, and chat benchmarks.

Reasoning models improve accuracy through extended chains of thought, but their long outputs create a memory and compute bottleneck. KV cache eviction methods reduce this cost by evicting unimportant key-value pairs from the cache, yet they suffer larger accuracy degradation than selection-based sparse attention alternatives, which keep the full KV cache. We identify key factors crucial to KV cache eviction accuracy. First, a small fraction of value states have abnormally large magnitudes, and evicting them causes catastrophic failure where models enter repetitive reasoning loops. Second, introducing stochasticity during eviction improves accuracy by increasing cache diversity. Based on these findings, we propose **V**alue-**a**ware **S**tochastic KV Cache **E**viction (VaSE), a training-free recipe that protects large-magnitude value states and promotes diverse eviction decisions. Across six reasoning tasks, Qwen3 models using VaSE with 4x KV cache compression achieve comparable or better average accuracies to the SOTA selection method under the same level of sparsity, while enabling a static memory footprint that selection methods cannot offer. Our method also generalizes as a recipe, with its key factors improving strong eviction methods by 5 points on average.

Continual recommendation captures dynamic user interests amid sequential interactions, enabling models to adapt to new observations while preserving prior valuable knowledge. Existing continual recommendation methods primarily preserve or reuse historical knowledge through replay, distillation, or regularization to mitigate forgetting during incremental updates. However, noisy or obsolete inherited representations render indiscriminate preservation detrimental by inducing memory conflicts with current stage preferences. Moreover, rapid shifts in user interests require timely and selective memory updates, while coarse global mechanisms fail to provide such fine-grained responsiveness. To address these issues, we propose VAMIRec, a value-aware memory intervention framework for continual recommendation. VAMIRec first constructs a memory state by separating inherited user memory into a slow anchor component and a fast-changing drift component. We further design a value-aware action evaluation module to generate three candidate operations, and estimate conservative action values by accounting for uncertainty and intervention cost. Finally, we develop a policy-guided memory intervention module that distills the training-time action supervision into an inference-safe policy and applies the selected memory action before all-item ranking. Extensive experiments on three real-world datasets demonstrate that VAMIRec consistently outperforms the state-of-the-art baselines.

The RISC-V Vector Extension (RVV) provides SIMD-style vector execution for accelerating deep learning (DL) inference on edge processors. However, existing low-rank compression methods mainly select ranks according to accuracy preservation and theoretical floating-point operation (FLOP) reduction, without considering whether the selected ranks are profitable under a target RVV effective vector length. As a result, a low-rank factorization that reduces FLOPs may still introduce tail-handling overhead or even increase the RVV instruction count under specific vector configurations. To address this problem, we propose VALOR, a low-rank restructuring framework for efficient DL deployment on RISC-V processors. Given a pretrained model and a target RVV configuration, VALOR identifies decomposable layers in the pretrained model, filters rank candidates using an RVV instruction-profitable condition, and searches for a global restructuring strategy with minimal accuracy loss. Furthermore, to avoid repeated end-to-end evaluation, VALOR uses a Hessian-aware accuracy predictor that combines layer-wise factorization error with inter-layer coupling. Experiments on Spike and a real RISC-V vector processor, SpacemiT X60, show that VALOR achieves a better accuracy-efficiency trade-off than baseline methods.

The efficiency and fidelity of 3D Gaussian Splatting critically depend on adaptive density control, which grows and suppresses Gaussian primitives throughout optimization. However, the standard pipeline still relies on heuristic view-space gradients, scale thresholds, and global opacity resets, rather than explicitly assessing the loss-reducing effect of each split, clone, or opacity update. This mismatch can allocate primitives to already-sufficient regions, miss under-reconstructed structures, and destabilize training through blanket opacity changes. In this work, we recast adaptive density control as a collection of local loss-reduction decisions. We derive efficient Taylor-based per-Gaussian surrogates that predict the objective change caused by three primitive-level operations: splitting, cloning, and opacity decay. This yields unified loss-aware framework with three components. First, we extend second-order splitting to a normalized joint position-scale space, enabling children to adapt not only their locations but also their anisotropic extents. Second, we formulate duplicate cloning as a surrogate minimization problem, selecting only Gaussians whose duplicated contribution is predicted to improve reconstruction and assigning each child a principled opacity. Third, we replace global opacity reset with selective soft opacity decay that weakens harmful primitives while preserving useful ones. Across standard 3DGS benchmarks, our method produces more targeted primitive allocation and achieves improved rendering quality with comparable or smaller Gaussian budgets compared to baselines.

In this paper, we propose UniGS, a unified map representation and differentiable framework for high-fidelity multimodal 3D reconstruction based on 3D Gaussian Splatting. Our framework integrates a CUDA-accelerated rasterization pipeline capable of rendering photo-realistic RGB images, geometrically accurate depth maps, consistent surface normals, and semantic logits simultaneously. We redesign the rasterization to render depth via differentiable ray-ellipsoid intersection rather than using Gaussian centers, enabling effective optimization of rotation and scale attribute through closed-form analytic depth gradients. Furthermore, we derive the analytic gradient formulation for surface normal rendering, ensuring geometric consistency among the reconstructed 3D scenes. To improve computational and storage efficiency, we introduce a learnable attribute that enables differentiable pruning of Gaussians with minimal contribution during training. Quantitative and qualitative experiments demonstrate the state-of-the-art reconstruction accuracy across several datasets, validating the efficacy and robust optimization stability of our geometry-aware paradigm.

We introduce $\textbf{UniCon3R}$, a unified feed-forward framework for online human-scene 4D reconstruction from monocular video. Current feed-forward human-scene reconstruction methods suffer from artifacts, where bodies float above the ground or penetrate parts of the scene. A key reason is the lack of effective interaction modelling between the human and the environment. Our goal is to exploit contact between the human and the scene during inference to actively improve the human mesh reconstruction. To that end, we explicitly model interaction by inferring 4D contact from the human pose and scene geometry and use the contact as a corrective cue for generating the pose. This enables UniCon3R to jointly recover scene geometry and spatially aligned 4D humans within the scene. Experiments on standard human-centric video benchmarks show that UniCon3R outperforms state-of-the-art baselines on physical plausibility and global human motion estimation while preserving fast, feed-forward inference speeds. The results validate our central claim: contact serves as a powerful internal prior, thus establishing a new paradigm for physically grounded joint human-scene reconstruction. Source code and models will be released upon acceptance.

Pairwise constrained clustering typically relies on hard must-link/cannot-link labels, whereas realistic pairwise supervision may be real-valued and entangle intrinsic ambiguity, expert judgment, and stochastic corruption. Existing deep constrained clustering (DCC) methods mainly target hard, expert-agnostic constraints, treating soft labels mostly numerically rather than semantically. We formalize this setting as uncertainty-aware probabilistic constrained clustering (UPCC), defining a canonical aleatoric target through a heterogeneous observation process and analyzing its conditional identifiability. We introduce ProbPair, an angular pairwise objective for probabilistic relations, and build ECI-PP, an estimator--corrector--integrator framework that refines imperfect supervision via belief estimation, correction, and reliability-aware integration. Across challenging probabilistic supervision settings, experiments on diverse benchmarks show that ECI-PP outperforms state-of-the-art DCC methods and remains robust with a shared default configuration.

Fine-grained visual classification (FGVC) with Multimodal Large Language Models (MLLMs) remains challenging, as visually similar subordinate categories inherently induce classification uncertainty due to subtle inter-class differences. Existing reinforcement learning methods typically require the model to generate a single class name and optimize it with sparse correctness rewards. However, a seemingly incorrect prediction can still provide highly informative signals if it falls within the same local confusion set as the ground-truth class. By treating all non-exact matches as equally wrong, the rigid single-answer paradigm overlooks these valuable near-misses. Consequently, it fails to capture the model's intrinsic uncertainty and provides limited learning signals. To address these limitations, we propose List-GRPO, an uncertainty-aware listwise Group Relative Policy Optimization framework. Rather than enforcing a single prediction, our method prompts the model to adaptively generate a ranked candidate list, explicitly capturing its predictive uncertainty. Furthermore, to mitigate the advantage vanishing when online exploration completely misses the target, we introduce a dynamic ground-truth anchored response strategy. We synthesize an off-policy anchor by prepending the ground truth to the most frequent hard negatives mined from online samples. To prevent the anchored response from dominating learning, we isolate the advantage estimation of online samples from the anchored response and use a gating coefficient to modulate its contribution. Extensive experiments on multiple fine-grained benchmarks demonstrate that List-GRPO significantly improves Top-1 accuracy while maintaining high ground-truth coverage with only about three candidate predictions on average.

Graph Contrastive Learning (GCL) is an effective approach for learning node representations. However, the intrinsic uncertainty of real-world graph data introduces significant challenges, as GCL relies on crisp deterministic representations that struggle to capture such ambiguity. To model graph uncertainty, fuzzy logic has attracted increasing attention due to its mathematical rigor. Existing methods, however, simply inject fuzzy modeling into the contrastive framework without tailoring data augmentation to the needs of fuzzy representations, resulting in limited discriminability and suboptimal downstream performance. To address these limitations, we propose a novel Fuzzy Graph Contrastive Learning (FGCL) framework for uncertainty-aware node representation learning. It adopts a vertex entanglement-based augmentation strategy to generate tailored multi-views with controlled perturbations while preserving core graph topology and semantics, mitigating semantic corruption. We also design a Deep Weighted Fuzzy Graph Convolutional Neural Network (DWFGCNN) encoder, which maps crisp features to fuzzy representations via learnable membership functions, explicitly models uncertainty, and resolves the core contradiction that traditional encoders cannot balance discriminability and robustness simultaneously. Extensive experiments on multiple datasets demonstrate that FGCL consistently outperforms baselines in node classification, community detection, and link prediction tasks, validating its effectiveness in handling uncertainty in graph representation learning.

Despite the promise of Neural Combinatorial Optimization (NCO), recent literature has increasingly coupled *decision paradigms*, *training objectives*, and *problem classes* with specific backbone architectures, limiting generic model design and fair cross-paradigm evaluation. We propose UECO, a simple yet effective **U**nified **E**ncoder for **C**ombinatorial **O**ptimization with a structure-aware attention mixture scheme, where a lightweight module defined upon graph-based locality is interleaved with conventional (global) node-focused attention blocks to dynamically evolve edge representations and inject local topological information into attention scores. Instead of fusing static edge features in a single step, UECO thereby integrates local and global messages in a progressive and problem-agnostic manner. UECO is orthogonal to task-specific decoders, and works seamlessly with *Local Construction* (LC), *Global Prediction* (GP), and *Adaptive Expansion* (AE) paradigms, across node- or edge-oriented problems, symmetric or asymmetric tasks, and sparse or dense graphs, for supervised, reinforcement, or generative learning. Extensive experiments show that, via plug-in substitution of encoders, UECO consistently improves solution and generalization quality over diverse backbones and task scales on TSP, ATSP, CVRP, ACVRP, MIS, MaxClique, and MaxCut.

Multimodal continual learning requires MLLMs to acquire new domains and abilities sequentially while retaining previous capabilities. MoE-based methods preserve task-specific knowledge, but inference relies on reliable routing. We instead study unified continual multimodal consolidation, which forms one shared model from sequential LoRA updates and projector shifts. LoRA merging naturally supports language-side consolidation, but extending it to MLLMs raises two challenges. First, sequential LoRA updates may interfere and overwrite directions important to earlier tasks. Second, projector mismatch may make the consolidated LoRA update incompatible with the final visual-language alignment. To address these challenges, we propose **CASC** (**C**onflict-**A**ware **S**pectral **C**onsolidation), a method that jointly consolidates LoRA and projector updates. CASC maintains fixed-rank spectral banks and uses a shared protected subspace memory rule to preserve dominant historical directions while incorporating compatible new updates under fixed rank budgets, yielding a single model without replay data or inference time routing. Both theoretical analysis and experimental results demonstrate the effectiveness of CASC in addressing multimodal continual learning.