NeurIPS 2026 Papers

Large language models can often identify useful semantic structure in formal artifacts, but their outputs cannot be trusted as proofs or solver decisions. We study whether LLMs can instead guide formal reasoning systems through a narrow, solver-verifiable interface. We instantiate this idea in quantified array SMT solving, where modern instantiation-based techniques can fail when key ground terms and equalities are hidden by auxiliary variables, axiom guards, and nested array terms. We observe that many instances are largely driven by a small set of focal ground terms or constraints, similar to the backdoor sets in SAT solving. Building on this, we present LinguaArray, a framework where an LLM proposes a small Semantic Focus Set (ground terms/constraints), while a conventional SMT solver remains the sole proof engine and certifies all results. LinguaArray uses these LLM-suggested, solver-validated finite sets to significantly enhance solver capability, solving additional satisfiable and unsatisfiable instances that the backend alone fails to solve. It interacts within a finite time and then falls back to the backend solver to mitigate potential regressions. Evaluation on 1015 SMT-LIB instances across five logics under 1200s timeout (including LLM latency) shows that LinguaArray solves up to 69.1\% of instances and increases solved-instance counts by 105\%--397\% over the corresponding backends.

Vision-language models (VLMs) are increasingly used for spatial tasks such as navigation and manipulation, where they must infer geometry and object relationships from visual input in order to act correctly. Existing benchmarks usually test perception and reasoning in isolation, making it hard to tell whether failures come from visual understanding, downstream reasoning, or the bridge between them. How can we evaluate whether a model can recover the right spatial structure from visual input and use it to make correct decisions? We introduce VeriWorld, a benchmark for spatial reasoning in interactive 3D environments with executable actions and deterministic verification. Each task is evaluated under three matched input settings -- visual-only, structured, and combined -- while the environment and objective remain fixed. This design isolates whether failures arise from perception, reasoning, or their interaction. VeriWorld brings together interactive 3D environments, code-based actions, deterministic verification, parameterized task generation, and controlled diagnostic evaluation in a single framework. Using this setup, we uncover two findings. First, models often succeed when given structured spatial information but fail when the same information must be inferred from visual input, revealing a recurring visual-to-structure gap. Second, action-space and harness design can change outcomes even under the same task and information condition, showing that interaction protocol is itself a confounding variable in spatial evaluation. VeriWorld is open-sourced to support reproducible and fine-grained evaluation of spatial reasoning in VLMs.

Existing benchmarks have laid the foundation for travel planning agents by establishing API-centric paradigms. However, as the capabilities of Autonomous Agents continue to advance, their evaluation must evolve beyond simple tool execution toward handling the inherent complexities of the open web. Current benchmarks bypass core cognitive hurdles: they fail to account for information noise, ignore multi-source factual contradictions, and overlook the necessity of grounding visual perception into logical planning. We introduce VeriTrip, a verifiable benchmark designed to meet the increasing demands for agent robustness and reliability. VeriTrip shifts the evaluation focus to evidence-grounded reasoning over unstructured multimodal web corpora. It establishes a Multimodal Retrieval Base (MRB) derived from real-world sources, forcing agents to autonomously orchestrate queries across heterogeneous data. A synchronized Verifiable Knowledge Base (VKB) enables a cell-wise verification protocol that precisely quantifies factual reliability, distinguishing systematic reasoning failures from parametric hallucinations. Our evaluations across leading MLLMs reveal a critical \textit{retrieval-reasoning trade-off}: the cognitive load of autonomous retrieval significantly erodes instruction retention. VeriTrip provides the rigorous foundation necessary for the next generation of planning agents capable of operating in unconstrained, multimodal environments.

Large language models (LLMs) are increasingly used in hardware-oriented coding workflows, yet open resources for evaluating first-pass RTL beyond execution remain limited. We present VeriScope, an open benchmark and evaluation suite of 568 problems spanning basic combinational gates through module-level designs and a 95-task L4+ top-end slice (92 L4 system tasks plus 3 L5 stress tests). A developer agent receives a natural-language task brief, returns a single RTL draft, and that artifact is evaluated through objective execution plus RTL-level and artifact-level review incorporating waveform and circuit evidence. Across 26 public models plus two 32B calibration baselines, the best systems reach about 84/100 combined score on the full benchmark but drop to the high 70s on L3–L4+. The 60/40 combined leaderboard largely tracks functional execution (Spearman 0.998 with a functional-only ranking), while artifact scores are most useful as a post-simulation screening signal: 29.6% of L3–L4+ simulation-passing submissions receive artifact score below 6 and therefore need additional verification evidence. A 100-sample manual taxonomy of such disagreements finds 70% testbench coverage gaps, 12% real RTL defects, and 18% judge hallucinations (Wilson 95% intervals reported in the analysis), showing that artifact review surfaces both under-tested passes and model defects, but should not be treated as a standalone leaderboard refinement.

The data fidelity term plays a crucial role in variational image segmentation. Recently, optimal transport (OT)-based variational models have improved segmentation by globally matching predicted feature distributions with reference distributions. However, existing OT-based methods usually rely on color or intensity similarity, which can be insufficient when foreground and background regions share similar appearance. We address this limitation by incorporating geodesic distance into the OT cost on a Riemannian feature manifold, allowing the transport cost to jointly encode spatial proximity, appearance similarity, and boundary information. The proposed model is well-defined: we prove existence of minimizers and convexity of the energy functional. It is also tractable: the OT terms admit differentiable transport-map representations, avoiding storage of the full pairwise transport matrix and enabling efficient gradient-based optimization. Experiments on BraTS and RESECT show that our method consistently outperforms traditional variational models, OT-based baselines, and prompt-based deep segmentation models, particularly when foreground and background have overlapping intensity or color patterns.

Value alignment of Large Language Models (LLMs) requires us to empirically measure these models' actual, acquired representation of value. Among the characteristics of value representation in humans is that they distinguish among value of different kinds. We investigate whether LLMs likewise distinguish three different kinds of good: moral, grammatical, and economic. By probing model behavior, embeddings, and residual stream activations, we report pervasive cases of value entanglement: a conflation between these distinct representations of value. Specifically, both grammatical and economic valuation was found to be overly influenced by moral value, relative to human norms. This conflation was repaired by selective ablation of the activation vectors associated with morality.

Radio astronomy is an indispensable discipline for studying distant celestial objects. Measurements of wave signals from radio telescopes, called visibility, need to be transformed into images for astronomical observations. These dirty images blend information from real sources and artifacts. Therefore, astronomers usually perform reconstruction before imaging to obtain cleaner images. Existing methods consider only a single modality of sparse visibility data, resulting in images with remaining artifacts and insufficient modeling of correlation. We propose VVTRec, a multimodal radio interferometric data reconstruction method, to enhance visibility information extraction and improve image-domain output quality. Since the information in sparse visibility is inherently limited, we transform it into image-form and text-form features. Therefore, we can leverage vision-language models to process the two derived modalities, providing knowledge banks as a supplement for reconstruction. The sparse visibility is accordingly utilized as the query to perform the integration and selection of multimodal external knowledge. Consequently, VVTRec improves the structural integrity and accuracy of reconstructed images by enriching spatial and semantic information. Our experiments demonstrate that VVTRec effectively enhances imaging results by exploiting multimodal information without introducing excessive computational overhead.

While virtual try-on has achieved significant progress, evaluating these models towards real-world scenarios remains a challenge: unpaired metrics (FID/KID) miss task-specific dimensions such as texture and consistency, and most test sets are limited to indoor scenarios. To address these needs, we introduce the Virtual Try-on Benchmark (VTBench), the first-ever hierarchical try-on benchmark suite that systematically decomposes virtual image try-on into hierarchical, disentangled dimensions, each equipped with tailored test sets and evaluation criteria. VTBench exhibits three key advantages: 1) Multi-Dimensional Evaluation Framework: The benchmark defines three top-level dimensions (General Image Quality, Garment Preservation, Auxiliary Consistency) and six fine-grained dimensions (Distributional Fidelity, Aesthetics, Texture Fidelity, Cross-Category Plausibility, Background Consistency, and Hand Consistency). Granular evaluation metrics and targeted test sets pinpoint model capabilities and limitations across diverse, challenging scenarios. 2) Human Alignment: Human preference annotations are provided for the five image-level dimensions, ensuring the benchmark's alignment with perceptual quality. 3) Valuable Insights: Beyond standard indoor settings, we analyze model performance variations across dimensions and investigate the disparity between indoor and real-world try-on scenarios. To foster the field of virtual try-on towards challenging real-world scenarios, VTBench will be open-sourced, including all datasets and evaluation algorithms.

Large models are increasingly becoming autonomous agents that interact with real-world environments and use external tools to augment their static capabilities. However, most recent progress has focused on text-only large language models, which are limited to a single modality and therefore have narrower application scenarios. On the other hand, multimodal large models, while offering stronger perceptual capabilities, remain limited to static knowledge and lack the ability to access and leverage up-to-date web information. In this paper, we propose VSearcher, turning static multimodal model into multimodal search agent capable of long-horizon, multi-turn tool use in real-world web environments, including text search, image search, and web browsing, via reinforcement learning. Specifically, we introduce Iterative Injection Data Synthesis pipeline to generate large-scale, complex multimodal QA questions, which are further filtered with comprehensive metrics to ensure high quality and sufficient difficulty. We then adopt an SFT-then-RL training pipeline to turn base multimodal models to agent capable of multi-turn tool calling in real-world web environments. Besides, we propose a multimodal search benchmark MM-SearchExam dedicated to evaluating search capabilities of multimodal search agents, which proves highly challenging for recent proprietary models. Extensive evaluations across multiple multimodal search benchmarks reveal effectiveness of our method. VSearcher achieves superior performance compared to recent multimodal search agents and even surpasses several proprietary models on multimodal web search tasks.

We introduce VSRo-200, the first large-scale dataset for visual speech recognition (lip reading) in Romanian, comprising 200 hours of real-world podcast videos. All samples are annotated with pseudo-labels generated by a fine-tuned Romanian ASR model, while a subset of 100 hours is additionally transcribed by humans, enabling controlled analysis of supervision quality under a unified framework. Building on this dataset, we establish a benchmark for visual speech recognition in low-resource settings. We systematically study the impact of supervision quality, showing that while human annotations provide better performance at fixed data scales, pseudo-labels enable continued improvements through scalability. We further evaluate robustness under domain shift using curated out-of-distribution (OOD) test sets, and analyze audio-visual speech recognition (AVSR) under noisy conditions, where multimodal fusion significantly improves robustness compared to audio-only models. Finally, we demonstrate that representations learned on VSRo-200 transfer effectively to the LRRo benchmark for isolated word recognition, substantially outperforming previously reported results. Overall, VSRo-200 provides a new testbed for studying supervision, domain generalization, and multimodal fusion in low-resource visual speech recognition.

Learning semantic representations for 3D Gaussian Splatting has recently emerged as a promising direction for 3D scene understanding. However, existing 2D-to-3D semantic lifting approaches rely primarily on 2D segmentation supervision and lack object-level priors, causing the learned representation to be driven by local mask evidence rather than holistic object structure. In this paper, we present VLSplat, a vision-language guided approach for object-centric semantic lifting in 3D Gaussian Splatting. Our method augments mask-based lifting with object-level semantic priors derived from vision-language models and refines Gaussian representations using an object-group scene graph. The refinement is performed through two language-guided modules: intra-group refinement suppresses semantic noise within object groups, while inter-group acquisition expands object support regions by incorporating structurally relevant candidates from neighboring groups. Extensive experiments on indoor scene datasets demonstrate that VLSplat improves semantic consistency and structural completeness. Our code and models are available at https://vlsplat.github.io/

Recent advancements in Multimodal Large Language Models (MLLMs) have enabled complex reasoning. However, existing remote sensing (RS) benchmarks remain heavily biased toward perception tasks, such as object recognition and scene classification. This limitation hinders the development of MLLMs for cognitively demanding RS applications. To address this, we propose a Vision Language ReaSoning Benchmark (VLRS-Bench), which is the first benchmark exclusively dedicated to complex RS reasoning. Structured across the three core dimensions of Cognition, Decision, and Prediction, VLRS-Bench comprises 2,000 question-answer pairs with an average question length of 130.19 words, spanning 14 tasks and up to eight temporal phases. VLRS-Bench is constructed via a specialized pipeline that integrates RS-specific priors and expert knowledge to ensure geospatial realism and reasoning complexity. Experimental results reveal significant bottlenecks in existing state-of-the-art MLLMs, providing critical insights for advancing multimodal reasoning within the remote sensing community.

Vision-language models (VLMs) achieve strong performance on multimodal benchmarks, but may still lack robust control over basic visual operations. We study \textit{line tracing}, where a model must follow a selected visual path through successive local continuations. To isolate this ability, we design controlled tracing tasks that introduce nearby competitors while reducing semantic and topological ambiguity such as crossings and overlaps. Across these tasks, even state-of-the-art VLMs frequently lose the target path and switch to nearby alternatives, especially when those alternatives look locally similar to the target. Behavioral interventions and internal analyses indicate that these failures arise from local competition: nearby similar distractors pull the model away from the true continuation. Standard remedies do not remove this bottleneck: model-size scaling provides only limited gains, reasoning partially compensates through costly substitute strategies, and explicit tracing instructions fail to recover stable path following. Finally, tests on tangled-cable scenes and metro maps with richer visual complexity show that the same path-switching failure persists beyond our controlled settings.

Vision Language Models (VLMs) enable a unified model to solve various vision tasks through prompting. They have shown promising performance in semantic understanding. However, 3D understanding still largely relies on expert vision models with complex task-specific designs. The key argument this work wants to make is that VLMs are native 3D learners. Our in-depth large scale study shows that 1) focal length unification, 2) text-based pixel reference and 3) data mixture and scaling, are all you need for effective 3D learning. Model architecture changes, large models, heavy data augmentations, and complex losses including the regression formulation, many of which form the foundation of expert vision models, are actually not necessary conditions. As a result, we propose VLM$^3$, a scalable method with the simplest design that enables standard VLMs to master diverse 3D tasks. VLM$^3$ not only advances the VLM depth estimation accuracy by a large margin (0.84 $\rightarrow$ 0.9), but also enables diverse 3D tasks such as pixel correspondence, camera pose estimation and object-level 3D understanding, matching expert vision model accuracy while maintaining standard architectures and text-based training. Code will be released to the community.

Vision-Language-Action (VLA) models have shown strong promise for general-purpose robotic manipulation, but their real-world evaluation remains limited by a lack of accessible, reproducible, and consistent benchmarks. Simulation benchmarks fail to capture real-world complexity, while existing real-world benchmarks often require expensive hardware, centralized evaluation, or are limited in task diversity. We introduce *VLA-REPLICA*, a low-cost, easily reproducible real-world benchmark for evaluating VLA models. Built from off-the-shelf components, our system can be quickly assembled and replicated across laboratories, providing a consistent environment for policy evaluation anywhere in the world. *VLA-REPLICA* includes a diverse suite of manipulation tasks and a small-scale demonstration dataset for target-domain adaptation, with real-world evaluation protocols for both in-distribution and out-of-distribution settings. Experiments with imitation learning and state-of-the-art VLA models reveal model strengths and limitations, while consistent results across independently constructed setups demonstrate the reproducibility of our benchmark.

Vision-based document retrieval has improved rapidly, but current evaluation settings still emphasize short documents and single relevant pages. This leaves an important gap between leaderboard performance and realistic long-document retrieval, where the evidence needed to answer a query may span multiple pages or even multiple documents. We present VL-DocIR, a page-level benchmark for evidence-complete visual long-document retrieval. VL-DocIR is built from 29,641 HTML-born documents rendered into 388,548 page images from Wikipedia, arXiv, PubMed, and SEC proxy statements. It contains 271,760 queries across 23 domains and six evidence structures, covering single-page, within-document multi-page, and cross-document evidence configurations. Evidence annotations are grounded to rendered pages and HTML element identifiers, and queries are filtered with a cleaning pipeline targeting clarity, correctness, closedness, and the absence of explicit layout references. We evaluate leading single-vector and multi-vector visual retrievers together with diagnostic retrieval settings such as document-context scoring, query splitting, reranking, and round-robin ensembles. The strongest evaluated configuration reaches 75.6 nDCGAll@10 and 86.2 RecallAll@10, but source- and evidence-structure breakdowns show that cross-document retrieval remains substantially harder than single-page retrieval, and that document-context scoring is especially helpful for within-document multi-page queries. VL-DocIR exposes these failure modes and provides a more demanding target for visual long-document retrieval.

Flow-based vision-language-action (VLA) policies provide a compelling recipe for robot control: they inherit broad behavioral priors from large-scale imitation and generate smooth, temporally extended continuous action chunks. The same properties, however, make offline post-training delicate. Mixed offline robot datasets contain expert behavior as well as partial completions and failures, requiring improvement without drifting far from the data support. An offline critic can in principle provide useful directions, but actor-side critic optimization may suffer from extrapolation and push high-dimensional action chunks off-support. In contrast, advantage-conditioned or reweighting-based methods are more stable, but tend to be conservative and restricted to actions already present in the dataset. We propose VISTA, a post-training framework that turns value estimates into support-anchored distillation targets for pretrained flow policies. VISTA queries a critic only at dataset actions, computes a normalized action-gradient direction, and uses this bounded direction to shift clean-action endpoints and velocity targets. A frozen flow teacher preserves the pretrained action prior, while a behavior-cloning anchor keeps the adapted targets close to the data distribution. The shaped supervision is distilled into a time-indexed action denoising (TAD) student, which predicts time-indexed clean-action estimates with a single network evaluation and obtains the executed action by an analytic final readout. We treat the induced target shift as conservative local guidance rather than a global policy-improvement guarantee. Across five BEHAVIOR-1K simulation tasks and five real-world bimanual manipulation tasks, VISTA achieves the best average success rate in our evaluation against behavior cloning (BC), advantage-conditioned BC, IDQL, and flow Q-learning, while reducing action-expert computation by $15\times$ (and end-to-end policy inference by $1.8\times$) relative to the $20$-step flow teacher.

Pathology vision-language models are advancing rapidly, yet existing benchmarks remain focused on human tissue, particularly oncology, leaving non-human pathology largely unaddressed. This gap is especially important in toxicologic pathology, where microscopic tissue examination of laboratory animals is a core component of preclinical drug safety assessment. To address it, we introduce VIPER, the first expert-curated benchmark for vision-language model evaluation in toxicologic pathology. VIPER contains 1251 questions associated with 419 H&E-stained rat histology images across 9 organs, covering multiple-choice, KPrim, and free-text formats. All questions were curated and validated by board-certified veterinary pathologists. In total, we benchmarked 16 models, including two newly introduced veterinary-pathology models, seven human pathology-specialized models, and seven general-purpose frontier models. The results identify a substantial domain gap between veterinary and human pathology, expose the risk of over-diagnosis of normal tissue in frontier models, and show that domain-specific training remains critical for visually grounded predictions. VIPER data and evaluation code are available at https://github.com/mahmoodlab/viper.

Multimodal discrete diffusion language models (dLLMs) generate responses through iterative mask prediction and offer a promising alternative to autoregressive large vision-language models. However, they still suffer from hallucination, producing outputs that are plausible under language priors but insufficiently grounded in the image. We argue that hallucination in multimodal dLLMs is not only a token prediction problem, but also a premature commitment problem: during iterative denoising, some masked positions are unmasked too early because their confidence is driven more by language priors than by visual evidence, and these early commitments can bias later generation. To address this issue, we propose Visual Gain Ordering (VIGOR), a training-free and plug-and-play inference strategy that reorders masked positions according to counterfactual visual evidence. At each denoising step, VIGOR compares the confidence of each candidate token under the original image-conditioned pass and an additional visual-ablation pass, and prioritizes positions whose predictions are more strongly supported by the image. Experiments on LLaDA-V and Lumina-DiMOO show that VIGOR consistently reduces hallucination and improves multimodal reasoning performance across benchmarks. Anonymous code is available at https://anonymous.4open.science/r/519_VIGOR-4051.