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2605.06156 2026-05-11 cs.LG cs.AI

Entropy-Regularized Adjoint Matching for Offline Reinforcement Learning

Abdelghani Ghanem, Mounir Ghogho

AI总结 本文提出了一种名为最大熵伴随匹配(ME-AM)的统一框架,旨在解决离线强化学习中因固定行为分布导致的流行度偏差和支撑绑定问题。该方法通过引入镜像下降熵最大化目标和混合行为先验,提升了策略的表达能力并扩展了探索范围,从而更有效地从离线数据中提取高回报动作。实验表明,ME-AM在多个稀疏奖励的连续控制环境中表现出优于或接近现有先进方法的性能。

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英文摘要

Integrating expressive generative policies, such as flow-matching models, into offline reinforcement learning (RL) allows agents to capture complex, multi-modal behaviors. While Q-learning with Adjoint Matching (QAM) stabilizes policy optimization via the continuous adjoint method, it remains inherently bound to the fixed behavior distribution. This dependence induces a \textit{popularity bias} that can suppress high-reward actions in low-density regions, and creates a \textit{support binding} that restricts off-manifold exploration. Existing workarounds, such as appending \textit{residual} Gaussian policies, often re-introduce the expressivity bottlenecks associated with unimodal distributions. In this work, we propose \textit{Maximum Entropy Adjoint Matching} (ME-AM), a unified framework that addresses these limitations within the continuous flow formulation. ME-AM incorporates two mechanisms: (1) a Mirror Descent entropy maximization objective that mitigates the popularity bias to facilitate the extraction of optimal policies from offline datasets, and (2) a \textit{Mixture Behavior Prior} that broadens the geometric support to encompass out-of-distribution high-reward regions. By exploring this extended geometry, ME-AM identifies robust actions while preserving the absolute continuity of the generative vector field. Empirically, ME-AM demonstrates competitive or superior performance compared to prior state-of-the-art (SOTA) methods across a diverse suite of sparse-reward continuous control environments.

2605.06115 2026-05-11 cs.AI

CrossCult-KIBench: A Benchmark for Cross-Cultural Knowledge Insertion in MLLMs

Zhen Zeng, Leijiang Gu, Feng Li, Jing Yu, Zenglin Shi

AI总结 多模态大语言模型(MLLMs)主要基于英语数据训练,因此在跨文化场景中常生成文化不适当或不协调的响应。为此,研究提出了跨文化知识插入任务,旨在使模型适应特定文化背景的同时保持其在其他文化中的原有行为。本文引入了CrossCult-KIBench基准,包含9800个基于图像的跨文化场景案例,用于评估知识插入的效果及其对非目标文化的潜在影响,并提出了一种基于记忆的条件知识插入方法(MCKI)作为基线,实验表明当前方法在文化适应与行为保持之间仍面临挑战,突显了开发更具文化适应性的MLLMs的重要性。

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英文摘要

Multimodal Large Language Models (MLLMs), trained primarily on English-centric data, frequently generate culturally inappropriate or misaligned responses in cross-cultural settings. To mitigate this, we introduce the task of cross-cultural knowledge insertion, which focuses on adapting models to specific cultural contexts while preserving their original behavior in other cultures. To facilitate research in this area, we introduce CrossCult-KIBench, a comprehensive evaluation benchmark for assessing both the effectiveness of knowledge insertion and its unintended side effects on non-target cultures. The benchmark includes 9,800 image-grounded cases covering 49 culturally relevant visual scenarios across English, Chinese, and Arabic language-culture groups. It supports evaluation in both single-insert and sequential-insert settings. We also propose Memory-Conditioned Knowledge Insertion (MCKI) as a baseline method. MCKI retrieves relevant cultural knowledge from an external memory using frozen MLLM representations, prepending matched entries as conditional prompts when applicable. Extensive experiments on CrossCult-KIBench reveal that current approaches struggle to balance effective cultural adaptation with behavioral preservation, highlighting a key challenge in developing culturally-aware MLLMs. Our work thus underscores an important research direction for developing more culturally adaptive and responsible MLLMs.

2605.05958 2026-05-11 cs.AI

Temporal Smoothness Doubly Robust Learning for Debiased Knowledge Tracing

Peilin Zhan, Wei Chen, Weilin Chen, Shuyi Pan, Ruichu Cai

AI总结 知识追踪(KT)是智能教育系统的核心,但其依赖的选择性观测教育日志会导致严重的选择偏差。为此,本文提出了一种双重稳健(DR)框架,结合倾向模型与误差填补模型,理论上保证了在任一模型准确时的无偏性。此外,针对KT的时序特性,研究进一步引入时间平滑性作为控制估计方差的关键因素,并据此提出时间平滑双重稳健(TSDR)方法,在保持无偏性的同时有效降低方差,实验表明该方法在多个真实数据集上显著提升了现有KT模型的性能。

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英文摘要

Knowledge Tracing (KT) is fundamental to intelligent education systems, yet relies on educational logs that are selectively observed. The non-random nature of exercise recommendations and student choices inevitably induces severe selection bias. Most existing KT methods neglect this issue, training on observed logs using standard empirical risk, which yields biased mastery estimates and accumulates errors in subsequent recommendations. To address this, we introduce a doubly robust (DR) formulation for KT that integrates a propensity model with an error imputation model, theoretically guaranteeing unbiasedness if either model is accurate. Beyond unbiasedness, in the sequential setting of KT, we identify that the estimator's performance is compromised by variance-dependent stochastic deviations that accumulate over time, thereby causing training instability and limiting performance. To mitigate this, we derive a generalization bound that explicitly characterizes the impact of estimator variance and identifies temporal smoothness as a key factor in controlling it. Building on these theoretical insights, we propose the Temporal Smoothness Doubly Robust (TSDR) framework. TSDR jointly optimizes the KT predictor and the imputation model with a smoothness regularizer, effectively reducing variance while preserving the unbiasedness guarantee of DR. Experiments on multiple real-world benchmarks demonstrate that TSDR consistently enhances various state-of-the-art KT backbones, underscoring the vital role of principled bias correction in KT.

2605.05949 2026-05-11 cs.AI cs.SE

MAS-Algorithm: A Workflow for Solving Algorithmic Programming Problems with a Multi-Agent System

Yuliang Xu, Xiang Xu, Yao Wan, Hu Wei, Tong Jia

AI总结 本文提出了一种名为MAS-Algorithm的多智能体系统工作流,用于解决算法编程问题。该方法受竞赛编程和算法工程师实践的启发,将问题求解过程分解为模块化阶段,支持结构化推理、工具集成与智能体间灵活协作,具有良好的扩展性和通用性。实验表明,该方法在多个基准测试中显著提升了模型的接受率,并在推理过程分析和组件替换研究中展示了其优越性与潜力。

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英文摘要

Algorithmic problem solving serves as a rigorous testbed for evaluating structured reasoning in AI coding systems, as it directly reflects a model's ability to perform structured reasoning in complex scenarios. Existing approaches predominantly rely on model-centric strategies, such as architectural modifications and data scaling, which are costly and offer limited interpretability. Alternative methods leveraging external tools or prompting techniques (e.g., chain-of-thought) are often fragmented and lack a unified framework. In this paper, we propose MAS-Algorithm, a systematic multi-agent workflow for algorithmic problem solving inspired by the practices of competitive programmers and algorithm engineers. Our framework decomposes the end-to-end solving process into modular stages, enabling structured reasoning, tool integration, and flexible coordination among agents. The design emphasizes both rigor and extensibility, allowing it to generalize across diverse problem types. Experimental results on a self-constructed benchmark demonstrate consistent improvements across multiple Qwen series models, achieving an average gain of 6.48% in acceptance rate. In contrast, parameter-efficient fine-tuning on the same data yields only a marginal improvement of 0.89%. We further observe a 4.72% gain on LiveCodeBench-Pro, along with consistent improvements across additional accuracy and efficiency metrics. Beyond performance gains, we conduct comprehensive analyses to better understand the reasoning process within the workflow, including error patterns and cross-scenario behaviors. We further perform customized replacement and ablation studies to explore the upper bound of the framework, showing that individual agents can contribute improvements of up to 27.7%. These results highlight the strong potential of MAS-Algorithm for advancing AI-driven algorithmic reasoning.

2605.05927 2026-05-11 cs.CL cs.SD eess.AS

Minimizing Modality Gap from the Input Side: Your Speech LLM Can Be a Prosody-Aware Text LLM

Wenqian Cui, Xiao-Hui Li, Daxin Tan, Qiyong Zheng, Irwin King

AI总结 该论文研究了语音大语言模型(SLM)与文本大语言模型(TLM)之间的模态差距问题,提出从输入端减少这一差距的新方法。作者设计了TextPro-SLM,通过结合统一的语音编码器WhisperPro和经过训练的LLM主干网络,使语音输入更接近具有韵律感知能力的文本模型。实验表明,TextPro-SLM在3B和7B规模下均取得最低的模态差距,并在副语言理解任务中表现出色,且仅需约1000小时的训练数据,展示了其高效性。

Comments Work in progress

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英文摘要

Speech large language models (SLMs) are typically built from text large language model (TLM) checkpoints, yet they still suffer from a substantial modality gap. Prior work has mainly attempted to reduce this gap from the output side by making speech generation more text-like, but the gap remains. We argue that the key remaining bottleneck lies on the input side. We propose TextPro-SLM, an SLM that makes spoken input more closely resemble that of a prosody-aware text LLM. TextPro-SLM combines WhisperPro, a unified speech encoder that produces synchronized text tokens and prosody embeddings, with an LLM backbone trained to preserve the semantic capabilities of the original TLM while learning paralinguistic understanding. Experiments show that TextPro-SLM achieves the lowest modality gap among leading SLMs at both 3B and 7B scales, while also delivering strong overall performance on paralinguistic understanding tasks. These gains are achieved with only roughly 1,000 hours of LLM training audio, suggesting that reducing the modality gap from the input side is both effective and data-efficient.

2605.05866 2026-05-11 cs.AI cond-mat.mtrl-sci cs.LG

XDecomposer: Learning Prior-Free Set Decomposition for Multiphase X-ray Diffraction

Hanyu Gao, Bin Cao, Yunyue Su, Tong-Yi Zhang, Qiang Liu

AI总结 XDecomposer 是一种无需先验知识的多相X射线衍射图谱分解框架,能够直接从实验数据中联合识别和分离多个相的晶体结构,无需依赖候选相列表或结构模板。该方法将多相衍射分析建模为集合预测问题,通过引入相查询驱动的分解机制和符合衍射物理规律的重构策略,实现了高精度的源分离和结构表征。实验表明,XDecomposer 在多种化学体系中显著提升了重构精度和相识别能力,为数据驱动的多相XRD分析提供了有效工具。

Comments 28pages, 8figures, 6tables

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英文摘要

Multiphase powder X-ray diffraction (PXRD) analysis remains a fundamental bottleneck in structure identification, as real-world synthesis often produces complex mixtures whose constituent phases (components) cannot be reliably disentangled. While recent advances in representation-based crystal retrieval and generation suggest the possibility of inferring structures directly from PXRD, existing approaches largely assume single-phase inputs and break down in multiphase settings. Here, we present XDecomposer, a prior-free framework for joint decomposition and identification of multiphase XRD patterns without requiring candidate phase lists, structural templates, or prior knowledge of phase number. We formulate multiphase diffraction analysis as a set prediction problem, where the model infers an unordered set of phase-resolved components, their mixture proportions, and corresponding structural representations within a unified architecture. A phase-query-driven decomposition mechanism, together with diffraction-consistent physical reconstruction, enables accurate source separation while preserving crystallographic fidelity. Extensive experiments on both simulated and experimental datasets show that XDecomposer substantially improves reconstruction accuracy and phase identification across diverse chemical systems, while maintaining strong generalization to unseen mixtures. These results provide a practical route toward data-driven, source-resolved multiphase XRD analysis and reduce long-standing dependence on prior-guided iteratively phase matching. The code is openly available at https://github.com/Licht0812/XDecomposer

2605.05806 2026-05-11 cs.LG

Retrieval from Within: An Intrinsic Capability of Attention-Based Models

Elad Hoffer, Yochai Blau, Edan Kinderman, Ron Banner, Daniel Soudry, Boris Ginsburg

AI总结 本文研究了基于注意力机制的编码器-解码器模型是否能够直接从其内部表示中进行检索,而非依赖外部检索系统。为此,作者提出了INTRA框架,通过解码器的注意力机制对预编码的证据块进行打分,并直接将其作为生成上下文使用,从而将检索与生成过程统一起来。实验表明,INTRA在问答任务中优于传统检索生成流水线,在证据召回率和端到端答案质量上均表现优异,展示了注意力模型本身已具备可被激发的内在检索能力。

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英文摘要

Retrieval-augmented generation (RAG) typically treats retrieval and generation as separate systems. We ask whether an attention-based encoder-decoder can instead retrieve directly from its own internal representations. We introduce INTRA (INTrinsic Retrieval via Attention), a framework where decoder attention queries score pre-encoded evidence chunks that are then directly reused as context for generation. By construction, INTRA unifies retrieval and generation, eliminating the retriever-generator mismatch typical of RAG pipelines. This design also amortizes context encoding by reusing precomputed encoder states across queries. On question-answering benchmarks, INTRA outperforms strong engineered retrieval pipelines on both evidence recall and end-to-end answer quality. Our results demonstrate that attention-based models already possess a retrieval mechanism that can be elicited, rather than added as an external module.

2605.05732 2026-05-11 cs.LG cs.AI

CRAFT: Forgetting-Aware Intervention-Based Adaptation for Continual Learning

Md Anwar Hossen, Fatema Siddika, Juan Pablo Munoz, Tanya Roosta, Ali Jannesari

AI总结 本文提出了一种名为CRAFT的持续学习框架,旨在解决大语言模型在持续适应新任务时容易出现的灾难性遗忘问题。该方法通过学习低秩干预来调整隐藏表示,而非直接更新模型权重,从而在保持模型原有能力的同时适应新任务。CRAFT结合了任务路由、正则化和表示合并三个阶段,利用KL散度作为统一目标,有效控制遗忘并提升模型性能,实验表明其在多个基准和不同规模模型上均优于基于LoRA的强基线方法。

Comments 24 pages

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英文摘要

Large language models (LLMs) can acquire new capabilities through fine-tuning, but continual adaptation often leads to catastrophic forgetting. We propose CRAFT, a continual learning framework that avoids updating model weights by instead learning low-rank interventions on hidden representations. CRAFT proceeds in three stages: it first routes each task to a group of similar tasks based on output-distribution divergence; it then fine-tunes the model using a Kullback-Leibler (KL) divergence against the group's prior state, which directly controls forgetting and determines convergence; finally, it merges interventions for the updated task into the shared representation using the same KL signal. This design unifies routing, regularization, and merging through a single KL-based objective. CRAFT improves overall performance and reduces forgetting compared to strong LoRA-based approaches across multiple benchmarks and model scales, while remaining robust to task ordering. These results suggest that controlling adaptation in representation space, guided by output-space divergence, provides a scalable and principled approach to continual learning in LLMs.

2605.05693 2026-05-11 cs.AI cs.LG

Saliency-Aware Regularized Quantization Calibration for Large Language Models

Yanlong Zhao, Xiaoyuan Cheng, Huihang Liu, Baihua He, Xinyu Zhang, Harrison Bo Hua Zhu, Wenlong Chen, Li Zeng, Zhuo Sun

AI总结 本文提出了一种名为SARQC的新型量化校准方法,用于提升大语言模型在低位宽部署下的性能。该方法通过引入正则化项,显式控制量化权重与原始浮点权重之间的偏差,从而降低因校准数据有限或不具代表性而导致的泛化风险。进一步地,SARQC结合显著性感知的正则化策略,使得量化过程更关注模型中关键部分的权重保持,实验表明该方法在多个大模型任务中有效提升了推理性能,且无需增加额外的推理开销。

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英文摘要

Post-training quantization (PTQ) is an effective approach for deploying large language models (LLMs) under memory and latency constraints. Most existing PTQ methods determine quantization parameters by minimizing a layer-wise reconstruction error on a predetermined calibration dataset, typically optimized via either scale search or Gram-based methods. However, from the perspective of generalization risk, existing PTQ calibration objectives based solely on empirical reconstruction error over limited or unrepresentative calibration data may move the quantized weights away from the original floating-point weights, potentially degrading downstream performance. To address this issue, we propose \emph{Regularized Quantization Calibration} (RQC), a unified framework that augments standard PTQ objectives with a regularizer that explicitly controls weight deviation from the original weights. We further generalize this framework to incorporate a saliency-aware regularizer, resulting in \emph{Saliency-Aware Regularized Quantization Calibration} (SARQC). The proposed regularization encourages quantized weights to remain close to the original weights during calibration, leading to improved generalization at inference time. SARQC integrates seamlessly into existing PTQ pipelines and enhances both scale-search-based and Gram-based methods under a unified formulation. Extensive experiments on dense and Mixture-of-Experts LLMs demonstrate consistent improvements in perplexity and zero-shot accuracy, without introducing additional inference overhead.

2605.05674 2026-05-11 cs.CV cs.AI cs.LG

EGA: Adapting Frozen Encoders for Vector Search with Bounded Out-of-Distribution Degradation

Dongfang Zhao

AI总结 该研究针对基于冻结视觉编码器的向量搜索系统在面对未见类别查询时性能下降的问题,提出了一种名为EGA的残差适配器方法。EGA通过零初始化、局部三元组损失和超球面投影三个核心设计,实现了对未见类别区域的有限扰动控制,同时保持对已见类别的充分优化。实验表明,EGA在多个分布外基准测试中显著提升了最差情况下的标签精度,并且适用于多种强大的编码器模型。

Comments added ack and github link

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英文摘要

Vector search systems built on frozen vision encoders face queries from unseen classes at deployment, yet existing adapter training collapses under this shift: high-capacity adapters with global contrastive losses silently reassign unseen-class samples to wrong seen-class clusters, dropping worst-case Label Precision by over 40 points below the frozen baseline in our tests. We propose Euclidean Geodesic Alignment (EGA), a residual adapter that couples three principles: zero initialization, local triplet loss, and hypersphere projection. These collectively induce a self-limiting dynamic: triplets that already satisfy a small margin stop producing gradients, so the adapter automatically stops updating where the local geometry is already correct. Our experiments show that at convergence $96.5\%$ of triplets are gradient-free, leaving unseen-class regions largely untouched while still enabling full-capacity refinement of seen classes. Across five diverse out-of-distribution (OOD) benchmarks, EGA achieves the highest worst-case Label Precision on the four primary splits and a consistent improvement on the fifth. The design also transfers to stronger backbones in addition to CLIP, and we provide an analytical justification linking gradient sparsity to bounded OOD perturbation.

2605.05615 2026-05-11 cs.LG cs.CY

LLMSpace: Carbon Footprint Modeling for Large Language Model Inference on LEO Satellites

Lei Jiang, Adrian Ildefonso, Daniel Loveless, Fan Chen

AI总结 本文提出了LLMSpace,首个用于建模在人工智能卫星上进行大语言模型推理碳足迹的框架。该方法综合考虑了运行碳排放、制造碳排放、卫星配套子系统、抗辐射硬件以及大语言模型特有的工作负载特征,揭示了在轨推理中碳足迹、延迟、硬件设计和使用寿命之间的关键权衡关系,为可持续的空间大模型推理提供了重要参考。

Comments 12 pages, 4 figures, 6 tables

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英文摘要

Large language models (LLMs) impose rapidly growing energy demands, creating an emerging energy and carbon crisis driven by large-scale inference. Solar-powered, AI-enabled low Earth orbit (LEO) satellites have been proposed to mitigate terrestrial electricity consumption, but their lifecycle carbon footprint remains poorly understood due to launch emissions, satellite manufacturing, and radiation-hardened hardware requirements. This paper presents \textit{LLMSpace}, the first carbon modeling framework for LLM inference on AI-enabled LEO satellites. LLMSpace jointly models operational and embodied carbon, peripheral subsystems, radiation-hardened accelerators and memories, and LLM-specific workload characteristics such as prefill-decode behavior and token generation. Using realistic satellite and GPU configurations, LLMSpace reveals key trade-offs among carbon footprint, inference latency, hardware design, and operational lifetime for sustainable space-based LLM inference. Source code: https://github.com/UnchartedRLab/LLMSpace.

2605.05583 2026-05-11 cs.AI cs.CL

Belief Memory: Agent Memory Under Partial Observability

Junfeng Liao, Qizhou Wang, Jianing Zhu, Bo Du, Rui Yan, Xiuying Chen

AI总结 在部分可观测环境中,智能体依赖外部记忆来积累长期知识,但现有方法通常将每个观测存储为确定性结论,忽略了其固有的不确定性和模糊性,从而导致自我强化的错误。为此,本文提出了一种名为BeliefMem的新方法,通过保留多个候选结论及其概率来存储观测信息,利用Noisy-OR规则动态更新概率,并在检索时同时呈现所有候选及其概率,从而保留不确定性并提升智能体的决策灵活性。实验表明,BeliefMem在多个基准测试中表现出色,尤其在数据有限的情况下仍能取得最佳性能。

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英文摘要

LLM agents that operate over long context depend on external memory to accumulate knowledge over time. However, existing methods typically store each observation as a single deterministic conclusion (e.g., inferring "API~X failed" from temporary errors), even though such observations are inherently partial and potentially ambiguous. By committing to one conclusion and discarding uncertainty, these methods introduce self-reinforcing error: the agent acts on the stored conclusion, never revisits alternatives, and reinforces the conclusion over time. To address this issue, we propose BeliefMem, which shifts the memory paradigm from committing to a single conclusion per observation to retaining multiple candidate conclusions with their probabilities. Concretely, BeliefMem stores the candidate conclusions as separate memory entries, each carrying a probability that is updated via Noisy-OR rules as new observations arrive. At retrieval, all candidates surface together with their probabilities, keeping alternatives visible to the agent. Since each conclusion in memory retains its probability, BeliefMem preserves the uncertainty that the deterministic paradigm discards, enabling the agent to act with high confidence on well-evidenced knowledge while retaining the capacity to update its confidence when new evidence arrives. Empirical evaluations on LoCoMo and ALFWorld benchmarks show that, even with limited data, BeliefMem achieves the best average performance, remarkably outperforming well-known baselines. More broadly, such probabilistic memory produces substantial gains and explores a new direction for agent memory in partially observable environments.

2605.05558 2026-05-11 cs.AI cs.CY

Who Prices Cognitive Labor in the Age of Agents? Compute-Anchored Wages

Siqi Zhu

AI总结 本文探讨了人工智能代理(AI agents)对认知劳动定价的影响,指出传统认为代理劳动具有高度弹性供给从而压低工资的观点存在机制错误。研究提出,代理本质上是一种将计算资本转化为认知劳动的生产技术,因此决定认知劳动均衡工资的市场应从劳动力市场转移到计算资本市场。基于要素定价理论,作者推导出“计算锚定工资”(CAW)边界,表明在替代性任务中,人类工资受计算资本租金、代理劳动的计算强度及相对生产率等因素的限制,结论表明认知劳动的定价权已不再由劳动力市场主导。

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英文摘要

A natural intuition about the economics of AI agents is that, because agents can be replicated at very low marginal cost, agent labor may be supplied highly elastically, placing downward pressure on cognitive-labor wages when it closely substitutes for human labor. We argue this framing is wrong in mechanism but partially correct in conclusion, and that the correction matters for both theory and policy. \textbf{Agents are not labor; they are a production technology that converts compute capital $K_c$ into effective units of cognitive labor $L_A$.} Once this is recognized, the elastic-supply margin that anchors the equilibrium wage migrates from the labor market to the compute capital market. Building on the classic factor-pricing framework \citep{mankiw2020}, we derive a \emph{Compute-Anchored Wage} (CAW) bound stating that, on tasks where human and agent-produced cognitive labor are substitutes, the competitive human wage is bounded above by $λ\cdot k \cdot r_c$, where $r_c$ is the rental rate of compute capital, $k$ is the compute intensity of one effective agent-produced cognitive labor unit, and $λ$ is the relative human-to-agent productivity. We generalize the result through constant elasticity of substitution (CES) aggregation, separate substitutable from complementary tasks, and discuss factor-share consequences. The conclusion is concise: \emph{the price-setter for cognitive labor is no longer the labor market.}

2605.04279 2026-05-11 cs.LG

Gradient Flow Structure and Quantitative Dynamics of Multi-Head Self-Attention

Ayan Pendharkar

AI总结 本文研究了多头自注意力机制的动力学行为,揭示其在单位球面上的梯度流结构。通过构建多头能量函数,作者分析了注意力头之间的几何干扰,并识别出阻碍单调性的径向阴影项,提出了保证单调性的充分条件。研究还发现异质注意力头具有加速聚类的特性,并在简化模型中推导出控制聚类行为的关键温度参数,为理解Transformer模型中的聚类与稳定性机制提供了理论依据。

Comments 20 pages, 5 figures

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英文摘要

Transformer self-attention can be interpreted as a gradient flow on the unit sphere, in which tokens evolve under softmax interaction potentials and tend to form clusters. While prior work has established clustering behavior for single-head attention, the multi-head setting remains less understood due to geometric interference between heads, which invalidates standard monotonicity arguments. In this work, we develop a theoretical framework for multi-head self-attention dynamics and resolve several open questions. We show that, under suitable conditions on the score matrices, a natural multi-head energy functional is non-decreasing along both flat and spherical dynamics. We identify the key obstruction to per-head monotonicity as radial shadow terms, which are projections of each head's output onto token directions, persisting even under orthogonality assumptions. We introduce a sufficient condition ensuring monotonicity and establish robustness to approximate orthogonality. In a simplified scalar-head regime with equiangular token configurations, we derive a closed-form expression for the critical inverse temperature governing clustering behavior, and show that heterogeneous heads exhibit super-additive clustering rates. In this regime, we also prove a separation in clustering time between ReLU and softmax attention in the linearized dynamics. Finally, we establish an entropy production identity and show that attention entropy increases monotonically toward equilibrium as clustering progresses. Our results provide a unified perspective on the dynamics of multi-head attention and clarify the mechanisms underlying clustering and stability in transformer models.

2605.03067 2026-05-11 cs.AI cs.GT

Computing Thiele Rules on Interval Elections and their Generalizations

Dimitris Avramidis, Alexandra Lassota, Ulrike Schmidt-Kraepelin, Adrian Vetta

AI总结 本文研究了在区间选举及其扩展领域中计算Thiele规则的问题,特别是比例批准投票(PAV)。尽管在候选人区间(CI)域中,Thiele规则可通过线性规划(LP)在多项式时间内求解,但在选民区间(VI)域中却面临计算复杂性挑战。作者证明了在VI域中,尽管约束矩阵不完全单模,标准LP仍存在整数最优解,并提出了一种快速求解算法。研究进一步扩展到更一般的选民-候选人区间(VCI)域和线性一致(LC)域,揭示了它们之间的包含关系,并提出了LC域的等价定义,为理解这类结构化偏好下的选举规则提供了新视角。

Comments 19 pages

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英文摘要

Approval-based committee voting has received significant attention in the social choice community. Among the studied rules, Thiele rules, and especially Proportional Approval Voting (PAV), stand out for desirable properties such as proportional representation, Pareto optimality, and support monotonicity. Their main drawback is that computing a Thiele outcome is NP-hard in general. A glimpse of hope comes from the fact that Thiele rules are better behaved under structured preferences. On the candidate interval (CI) domain, they are computable in polynomial time via a linear program (LP) that has a totally unimodular constraint matrix. Surprisingly, this approach fails for the related voter interval (VI) domain, and the complexity of the problem has repeatedly been posed as an open question. Our main result resolves this question: although the relevant matrix is not totally unimodular, the ``standard'' LP still admits at least one optimal integral solution, and we provide a fast algorithm for finding it. Our technique naturally extends to the voter-candidate interval (VCI) domain, also known as the 1-dimensional voter-candidate range (1D-VCR) domain, and to the linearly consistent (LC) domain, both of which generalize the candidate and voter interval domains. Although both the VCI and LC domains have been studied in social choice, their relationship was unknown. We show, through connections to graph theory, that LC strictly contains VCI. We also provide an alternative definition of LC that is closer in spirit to VCI and has a natural interpretation in approval elections; this equivalence may be of independent interest. Finally, we study an alternative tree-based generalization of VCI and show that Thiele rules become NP-hard to compute on this domain.

2605.02971 2026-05-11 cs.LG cs.AI cs.CL

Multilingual Safety Alignment via Self-Distillation

Ruiyang Qin, Qingzhuo Wang, Dongrui Liu, Qiang Li, Zhihua Wei, Wen Shen

AI总结 大型语言模型在多语言安全对齐方面存在严重问题:它们在高资源语言中具有较强的安全防护能力,但在低资源语言中却极易受到越狱攻击。本文提出了一种跨语言安全能力迁移框架——多语言自蒸馏(MSD),无需依赖各语言的高质量响应数据,即可将高资源语言中的安全能力迁移至低资源语言。该方法引入了双视角安全加权机制(DPSW),通过联合考虑教师模型与学生模型的视角,动态调整安全关键词的惩罚权重,从而提升跨语言安全对齐效果。实验表明,该方法在多种多语言越狱和实用基准测试中均取得了优越的安全性能,并能有效推广到更具挑战性的数据集和未见过的语言。

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英文摘要

Large language models (LLMs) exhibit severe multilingual safety misalignment: they possess strong safeguards in high-resource languages but remain highly vulnerable to jailbreak attacks in low-resource languages. Current safety alignment methods generally rely on high-quality response data for each target language, which is expensive and difficult to generate. In this paper, we propose a cross-lingual safeguard transfer framework named Multilingual Self-Distillation (MSD). This framework transfers an LLM's inherent safety capabilities from high-resource (e.g., English) to low-resource (e.g., Javanese) languages, overcoming the need for response data in any language. Our framework is flexible and can be integrated with different self-distillation strategies. Specifically, we implement two concrete methods -- on-policy MSD and off-policy MSD -- both of which enable effective cross-lingual safety transfer using only multilingual queries. Furthermore, we propose Dual-Perspective Safety Weighting (DPSW), a divergence measure to optimize the distillation objective. By jointly considering the perspectives of both the teacher and the student, DPSW adaptively increases the penalty weights on safety-critical tokens while reducing the weights on non-critical tokens. Extensive experiments on representative LLMs across diverse multilingual jailbreak and utility benchmarks demonstrate that our method consistently achieves superior multilingual safety performance. Notably, it generalizes effectively to more challenging datasets and unseen languages while preserving the model's general capabilities.

2605.02881 2026-05-11 cs.RO

MolmoAct2: Action Reasoning Models for Real-world Deployment

Haoquan Fang, Jiafei Duan, Donovan Clay, Sam Wang, Shuo Liu, Weikai Huang, Xiang Fan, Wei-Chuan Tsai, Shirui Chen, Yi Ru Wang, Shanli Xing, Jaemin Cho, Jae Sung Park, Ainaz Eftekhar, Peter Sushko, Karen Farley, Angad Wadhwa, Cole Harrison, Winson Han, Ying-Chun Lee, Eli VanderBilt, Rose Hendrix, Suveen Ellawela, Lucas Ngoo, Joyce Chai, Zhongzheng Ren, Ali Farhadi, Dieter Fox, Ranjay Krishna

AI总结 本文提出 MolmoAct2,一种专为实际部署设计的全开放动作推理模型,旨在解决当前视觉-语言-动作(VLA)模型在真实环境中应用时存在的性能与部署限制。研究引入了 MolmoER 作为专用的视觉-语言模型骨干,结合大规模数据训练提升空间与具身推理能力,并发布多个新数据集和 OpenFAST 动作编码器,同时改进模型架构以提升推理效率。实验表明,MolmoAct2 在多个仿真和现实基准测试中优于现有先进模型,显著提升了动作推理的实用性与可靠性。

Comments 31 pages, project page: https://allenai.org/blog/molmoact2

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Vision-Language-Action (VLA) models aim to provide a single generalist controller for robots, but today's systems fall short on the criteria that matter for real-world deployment. Frontier models are closed, open-weight alternatives are tied to expensive hardware, reasoning-augmented policies pay prohibitive latency for their grounding, and fine-tuned success rates remain below the threshold for dependable use. We present MolmoAct2, a fully open action reasoning model built for practical deployment, advancing its predecessor along five axes. We introduce MolmoER, a VLM backbone specialized for spatial and embodied reasoning, trained on a 3.3M-sample corpus with a specialize-then-rehearse recipe. We release three new datasets spanning low-to-medium cost platforms, including MolmoAct2-BimanualYAM, 720 hours of teleoperated bimanual trajectories that constitute the largest open bimanual dataset to date, together with quality-filtered Franka (DROID) and SO100/101 subsets. We provide OpenFAST, an open-weight, open-data action tokenizer trained on millions of trajectories across five embodiments. We redesign the architecture to graft a flow-matching continuous-action expert onto a discrete-token VLM via per-layer KV-cache conditioning. Finally, we propose MolmoThink, an adaptive-depth reasoning variant that re-predicts depth tokens only for scene regions that change between timesteps, retaining geometric grounding at a fraction of prior latency. In the most extensive empirical study of any open VLA to date, spanning 7 simulation and real-world benchmarks, MolmoAct2 outperforms strong baselines including Pi-05, while MolmoER surpasses GPT-5 and Gemini Robotics ER-1.5 across 13 embodied-reasoning benchmarks. We release model weights, training code, and complete training data. Project page: https://allenai.org/blog/molmoact2

2605.02206 2026-05-11 cs.CV cs.LG

Metric Unreliability in Multimodal Machine Unlearning: A Systematic Analysis and Principled Unified Score

Abdullah Ahmad Khan, Hamid Laga, Ferdous Sohel

AI总结 本文系统分析了多模态机器遗忘任务中评估指标的可靠性问题,指出当前常用的五种指标在不同基准测试中对方法的排名存在显著冲突。研究提出了一种统一质量得分(UQS),通过结合各指标与理想模型距离的相关性进行加权,显著提升了评估的一致性和稳定性,并在多个实验中验证了其有效性。该工作为多模态模型的遗忘评估提供了更可靠的方法指导。

Comments 9 Pages , 6 figures, Neurips 2026

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英文摘要

Machine unlearning in Vision-Language Models (VLMs) is required for compliance with the General Data Protection Regulation (GDPR), yet current evaluation practices are inconsistent. We present the first systematic study of metric reliability in multimodal unlearning. Five standard metrics, Forget Accuracy (FA), Retain Accuracy (RA), Membership Inference Attack (MIA), Activation Distance (AD), and JS divergence (JS), yield conflicting method rankings across three VQA benchmarks (MLLMU-Bench, UnLOK-VQA, MMUBench). Kendall tau analysis over 36 unlearned LLaVA-1.5-7B models reveals two opposing clusters, {FA, RA, MIA} and {AD, JS}, with tau_FA_AD = -0.26, reproduced on BLIP-2 OPT-2.7B. Agreement is lower in multimodal VQA (average tau = 0.086) than in unimodal classification (average tau = 0.158; difference = 0.072), indicating that dual image-and-text pathways amplify inconsistency. We introduce the Unified Quality Score (UQS), a composite metric with weights derived from each metric's Spearman correlation with the oracle distance d(M_hat, M_star), where M_star is the oracle model retrained only on the retain set. RA shows the strongest reliability (rho = 0.484, p = 0.003), while FA is negatively correlated (rho = -0.418, p = 0.011). UQS yields stable rankings under 100 random weight perturbations (tau = 0.647 +- 0.262). We release the benchmark, 36 checkpoints, and an interactive leaderboard. Code and pre-computed results are available at https://github.com/neurips26/UnifiedUnl.

2605.02201 2026-05-11 cs.CV

Super-Resolution of Airborne Laser Scanning Point Clouds for Forest Inventory

Jinyuan Shao, Sangyoong Park, Chunxi Zhao, Ayman Habib, Songlin Fei

AI总结 该研究针对航空激光扫描(ALS)点云在森林调查中因点云稀疏和噪声导致的树木个体识别不准确问题,提出了一种基于三维卷积神经网络的深度学习模型3DFSR,用于同时提升点云密度和降低噪声。实验表明,该方法在温带和寒带森林数据集上均优于现有算法,显著提高了树干检测、胸径估计和树干重建的精度。此外,该方法适用于不同密度的点云数据,并可在不同激光雷达平台的数据间通用,无需迁移学习。

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Airborne Laser Scanning (ALS) can collect point clouds across large areas, enabling large-scale forest inventory. However, ALS point clouds are sparse and noisy, resulting in inaccurate individual-tree-level forest inventory, such as stem localization and tree size estimation. To overcome this problem, we propose a deep learning model, 3D Forest Super Resolution (3DFSR), to simultaneously improve point density and reduce noise for ALS forest point cloud. 3DFSR is a voxel-based CNN with a U-Net architecture. The proposed 3DFSR is evaluated on ALS point clouds collected in both temperate forests in the U.S. and boreal forests in Germany. Experimental results demonstrate that 3DFSR can generate finer point clouds of tree structure than other state-of-the-art point cloud super-resolution algorithms, achieving 0.249 m Chamfer Distance and 2.711 m Hausdorff Distance. Furthermore, to verify the effectiveness of 3DFSR point clouds in forest inventory, we conduct stem detection, DBH measurements, and stem reconstruction on both original ALS point clouds and 3DFSR enhanced point clouds. We find that stem detection and reconstruction algorithms developed for TLS/MLS point clouds can directly work on our 3DFSR point clouds, and DBH can be derived with circle-fitting method. F1 score of stem detection is improved from 0.71 on original ALS point clouds to 0.97 on 3DFSR point clouds; DBH estimation improves from 13.45 cm RMSE using allometric equations to 6.43 cm using circle fitting; comparing to stems reconstruction from MLS point clouds, stem reconstructed from 3DFSR point clouds has 0.170 m of Chamfer Distance and 0.377 m of Hausdorff Distance, and 0.95 R2 volume estimation. Finally, we find that the proposed 3DFSR is applicable to process point densities from 10 to 1700 points/m2; it also can be generalized across data collected from different LiDAR platforms without transfer learning.

2605.01999 2026-05-11 cs.AI

TumorXAI: Self-Supervised Deep Learning Framework for Explainable Brain MRI Tumor Classification

Abrar Hossain Zahin, Amit Kumar Saha, Tanvir Mridha, Saifur Rahman, Jannatul Ferdous Prome, Raima Husna, Israt Jahan, Ahmed Wasif Reza

AI总结 本文提出了一种名为 TumorXAI 的自监督深度学习框架,用于实现可解释的脑部MRI肿瘤分类。该方法基于ResNet-50网络,结合多种自监督学习方法(如SimCLR、BYOL等)在包含17种肿瘤类型的4,448张MRI图像数据集上进行训练与评估,显著提升了分类性能,并在有限标签情况下优于传统监督模型。通过引入Grad-CAM等可解释性技术,模型不仅实现了高精度分类,还增强了决策过程的可视化与可解释性。

Comments 16 pages, 9 figures, 6 Tables

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Classifying brain tumors using magnetic resonance imaging (MRI) is crucial for early diagnosis and treatment; however, tumor heterogeneity and a dearth of annotated datasets restrict the use of supervised deep learning approaches. In this work, we use self-supervised learning (SSL) to study multi-class brain tumor classification. Using a ResNet-50 backbone, we evaluate four SSL frameworks including SimCLR, BYOL, DINO, and Moco v3 on a publicly available dataset of 4,448 MRIs with 17 distinct tumor types. On the dataset, SimCLR achieved 99.64% accuracy, 99.64% precision, 99.64% recall, and 99.64% F1-score. The workflow includes preprocessing, fine-tuning, linear evaluation, and SSL pretraining with data augmentations. Results show that, when labels are limited, SSL-pretrained models outperform supervised baselines in terms of F1-score, recall, accuracy, and precision. Additionally, by providing visual insights into model decisions, Explainable AI techniques (Grad-CAM, Grad-CAM++, EigenCAM) enhance interpretability. These results demonstrate SSL's scalability and dependability in diagnosing brain tumors from unlabeled medical data.

2605.01862 2026-05-11 cs.LG

QHyer: Q-conditioned Hybrid Attention-mamba Transformer for Offline Goal-conditioned RL

Xing Lei, Jincheng Wang, Xuetao Zhang, Donglin Wang

AI总结 该论文提出了一种名为QHyer的新型离线目标条件强化学习框架,用于解决现实环境中数据部分可观测和历史依赖所带来的挑战。QHyer通过引入一个基于状态条件的Q估计器替代传统的返回值目标(RTG),增强了不同轨迹之间的行为拼接能力,并采用门控混合注意力-Mamba结构,在保持局部动态的同时实现内容自适应的历史压缩。实验表明,QHyer在非马尔可夫和马尔可夫数据集上均取得了最先进的性能,验证了其在多样化场景中的有效性。

Comments ICML 2026

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Offline goal-conditioned RL (GCRL) learns goal-reaching policies from static datasets, but real-world datasets are often partially observable and history-dependent, exhibiting a mix of Markovian and non-Markovian that violate standard RL assumptions. History-aware sequence models such as Decision Transformer (DT) are a natural fit for long-term dependency modeling, yet pure attention is inefficient and brittle when handling local Markovian structure and long-range context simultaneously. Although recent hybrid architectures (e.g., LSDT) introduce local extractors to improve local dependencies modeling, the fixed-window extraction cannot adapt its effective memory to varying dependency lengths in temporally heterogeneous settings, often truncating long-range context rather than compressing its content adaptively. Moreover, sequential offline GCRL faces a key bottleneck: under sparse rewards, return-to-go (RTG) becomes non-discriminative across sub-trajectories, providing little guidance signal for stitching goal-reaching behaviors from diverse demonstrations. To address these, we propose \textbf{QHyer}, which replaces RTG with a flow-parameterized, state-conditioned goal-reaching Q-estimator to support stitching across demonstrations, and introduces a gated Hybrid Attention-Mamba backbone that performs content-adaptive history compression while preserving local dynamics. Extensive experiments demonstrate that \textbf{QHyer} achieves state-of-the-art performance on both non-Markovian and Markovian datasets, validating its effectiveness for diverse scenarios.

2605.01717 2026-05-11 cs.CL cs.AI

TCDA: Thread-Constrained Discourse-Aware Modeling for Conversational Sentiment Quadruple Analysis

Xinran Li, Xinze Che, Yifan Lyu, Zhiqi Huang, Xiujuan Xu

AI总结 本文研究多轮对话中的情感四元组分析问题,旨在捕捉对话中复杂的语义关系。为解决现有方法在结构噪声、时序建模和距离稀释问题上的不足,提出了一种结合线程约束有向无环图(TC-DAG)和话语感知旋转位置嵌入(D-RoPE)的新框架,有效提升了对话情感分析的准确性和鲁棒性。实验表明,该方法在两个基准数据集上取得了当前最优的性能。

Comments Accepted to IJCAI 2026 (Main Track)

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英文摘要

Conversational Aspect-based Sentiment Quadruple Analysis (DiaASQ) needs to capture the complex interrelationships in multiple rounds of dialogues. Existing methods usually employ simple Graph Convolutional Networks (GCN), which introduce structural noise and fail to consider the temporal sequence of the dialogues, or use standard RoPE, which implicitly captures relative distances in a flat sequence but cannot clearly separate the token-level syntactic order from the utterance-level progression, and may suffer from the Distance Dilution problem. To address these issues, we propose a new framework that combines Thread-Constrained Directed Acyclic Graph (TC-DAG) and Discourse-Aware Rotary Position Embedding (D-RoPE). Specifically, TC-DAG filters out cross-thread noise based on thread constraints, maintains global connectivity through root anchoring, and incorporates the temporal sequence of the dialogues. D-RoPE aligns multi-layer semantics using dual-stream projection and multi-scale frequency signals, captures thread dependencies using tree-like distances, and alleviates the token-level Distance Dilution problem by incorporating utterance-level progressions. Experimental results on two benchmark datasets demonstrate that our framework achieves state-of-the-art performance.

2605.01459 2026-05-11 cs.CV cs.AI

SRGAN-CKAN: Expressive Super-Resolution with Nonlinear Functional Operators under Minimal Resources

Roberto Isai Navaro-Aviña, Eduardo Said Merin-Martinez, Andres Mendez-Vazquez, Eduardo Rodriguez-Tello

AI总结 本文提出了一种名为SRGAN-CKAN的混合超分辨率框架,旨在在有限计算资源下提升图像超分辨率的表达能力。该方法通过将卷积操作重新表述为基于样条的非线性块变换,引入卷积型Kolmogorov-Arnold网络(CKAN),从而在局部区域更有效地建模复杂结构和高频纹理。实验表明,该方法在保持重建保真度的同时提升了感知质量,在计算资源受限的情况下表现出优越的效率和性能。

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Single-Image Super-Resolution (SISR) aims to reconstruct a High-Resolution (HR) image from a Low-Resolution (LR) observation, a fundamentally ill-posed problem where high-frequency details are severely degraded at large upscaling factors. Recent advances have been driven by transformer-based architectures and diffusion models improve global context modeling and perceptual quality at the cost of increased computational complexity. In contrast, this work focuses on enhancing the expressivity of local operators under minimal resources. We propose SRGAN--CKAN, a hybrid super-resolution framework that integrates Convolutional Kolmogorov--Arnold Networks (CKAN) into an adversarial learning setting reformulating convolution as a nonlinear patch-based transformation. The proposed operator replaces linear local mappings with spline-based functional representations, allowing expressive modeling of complex local structures and high-frequency textures using minimal hardware resources. Experimental results demonstrate that the proposed approach improves perceptual quality while preserving reconstruction fidelity, achieving a favorable balance between distortion-based and perceptual metrics. These results are obtained under constrained computational settings, highlighting the efficiency of the proposed formulation. Overall, this work introduces a complementary direction to existing approaches by improving the representational power of local transformations, providing an efficient and scalable alternative to globally intensive architectures.

2605.01333 2026-05-11 cs.CL

OralMLLM-Bench: Evaluating Cognitive Capabilities of Multimodal Large Language Models in Dental Practice

Rongyang Wang, Shuang Zhou, Jiashuo Wang, Wenya Xie, Xiaoxia Che

AI总结 本文提出了一种名为OralMLLM-Bench的综合基准,用于评估多模态大语言模型在牙科影像分析中的认知能力。该基准涵盖根尖片、全景片和侧位头颅片三种关键影像模态,定义了感知、理解、预测和决策四个认知类别,并基于公开数据集构建了27个临床相关任务,包含3,820份专家评估结果。研究对比了六种前沿模型与临床医生的性能差异,揭示了模型的优势与局限,并为改进模型提供了建议,有助于推动与临床认知和工作流程更契合的牙科人工智能系统发展。

Comments 21 pages, 4 figures, 5 tables

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Multimodal large language models (MLLMs) have emerged as a promising paradigm for dental image analysis. However, their ability to capture the multi-level cognitive processes required for radiographic analysis remains unclear. Here, we present a comprehensive benchmark to evaluate the cognitive capabilities of MLLMs in dental radiographic analysis. It spans three critical imaging modalities, i.e., periapical, panoramic, and lateral cephalometric radiographs, and defines four cognitive categories: perception, comprehension, prediction, and decision-making. The benchmark comprises 27 clinically grounded tasks derived from public datasets, with manually curated annotations and 3,820 clinician assessments for evaluation. Six frontier MLLMs, including GPT-5.2 and GLM-4.6, are evaluated. We demonstrate the performance gap between MLLMs and clinicians in dental practice, delineate model strengths and limitations, characterize failure patterns, and provide recommendations for improvement. This data resource will facilitate the development of next-generation artificial intelligence systems aligned with clinical cognition, safety requirements, and workflow complexity in dental practice.

2605.01240 2026-05-11 cs.LG cs.AI

Rhamba: Region-Aware Hybrid Attention-Mamba Framework for Self-Supervised Learning in Resting-State fMRI

Ruthwik Reddy Doodipala, Pankaj Pandey, Pratheek Eranki, Carolina Torres-Rojas, Manob Jyoti Saikia, Ranganatha Sitaram

AI总结 本文提出了一种名为Rhamba的区域感知混合注意力-Mamba框架,用于静息态功能磁共振成像(fMRI)的自监督学习。该方法结合解剖学引导的掩码策略与混合的注意力-Mamba架构,通过不同空间特异性的掩码策略在ABIDE数据集上进行预训练,并在精神分裂症和注意缺陷多动障碍分类任务中取得了优越的性能。实验表明,混合架构中的Mamba-Attention(MA)配置在多个数据集上表现最佳,且模型预测的可解释性分析揭示了掩码策略与网络结构之间的复杂交互关系。

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Self-supervised pretraining is promising for large-scale neuroimaging, yet the impact of region-aware masking and hybrid sequence modeling remains underexplored. In this work, we introduce Rhamba, a region-aware pretraining framework that integrates anatomically guided masking with hybrid Attention-Mamba architectures for resting state functional magnetic resonance imaging (fMRI) analysis. Models were pretrained on the ABIDE dataset using region-aligned patch embeddings and three masking strategies (Any, Majority, and Pure) with increasing spatial specificity. We evaluated four architectural variants: a Mamba only model, an Alternate architecture with interleaved Mamba and Attention blocks, and two hybrid encoder-decoder configurations (Attention-Mamba (AM) and Mamba-Attention (MA)). The pretrained models were fine-tuned on downstream classification tasks using the COBRE and ADHD-200 datasets for schizophrenia and attention-deficit/hyperactivity disorder discrimination. We employed Integrated Gradients, an explainable AI method, to identify the brain regions contributing to model predictions. Masking strategy strongly influenced reconstruction behavior, with reconstruction loss following a consistent ordering (Any > Majority > Pure). However, this trend did not directly translate into downstream performance, where differences were modest and dataset-dependent. The hybrid architecture with the MA configuration achieved the highest average AUROC across both datasets, and Rhamba outperformed state-of-the-art methods in comparative evaluation. Region-wise analysis showed that peak performance depends on the interaction between masking strategy and architecture rather than a single dominant configuration. Overall, Rhamba offers a flexible framework for balancing interpretability, scalability, and performance in large-scale fMRI representation learning.

2605.01195 2026-05-11 cs.RO

TAIL-Safe: Task-Agnostic Safety Monitoring for Imitation Learning Policies

Riad Ahmed, Momotaz Begum

AI总结 TAIL-Safe 是一种面向模仿学习策略的安全监控方法,旨在解决其在实际部署中因初始条件敏感和近似误差导致的失败问题。该方法通过构建一个基于可见性、可识别性和可抓取性三个任务无关指标的连续Q值函数,识别策略能够安全执行任务的状态-动作集合,并利用梯度上升机制引导策略回归安全区域。实验表明,TAIL-Safe 能有效提升模仿学习策略在运行时扰动下的任务成功率。

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英文摘要

Recent imitation learning (IL) algorithms such as flow-matching and diffusion policies demonstrate remarkable performance in learning complex manipulation tasks. However, these policies often fail even when operating within their training distribution due to extreme sensitivity to initial conditions and irreducible approximation errors that lead to compounding drift. This makes it unsafe to deploy IL policies in the field where out-of-distribution scenarios are prevalent. A prerequisite for safe deployment is enabling the policy to determine whether it can execute a task the way it was learned from demonstrations. This paper presents TAIL-Safe, a principled approach to identify, for a trained IL policy, a safe set from where the policy empirically succeeds in completing the learned task. We propose a Lipschitz-continuous Q-value function that maps state-action pairs to a long-term safety score based on three short-term task-agnostic criteria: visibility, recognizability, and graspability. The zero-superlevel set of this function characterizes an empirical control invariant set over state-action pairs. When the nominal policy proposes an action outside this set, we apply a recovery mechanism inspired by Nagumo's theorem that uses gradient ascent to the Q-function to steer the policy back to safety. To learn this Q-function, we construct a high-fidelity digital twin using Gaussian Splatting that enables systematic collection of failure data without risk to physical hardware. Experiments with a Franka Emika robot demonstrate that flow-matching policies, which fail under run-time perturbations, achieve consistent task success when guided by the proposed TAIL-Safe.

2605.01006 2026-05-11 cs.CL cs.CY

Can AI Debias the News? LLM Interventions Improve Cross-Partisan Receptivity but LLMs Overestimate Their Own Effectiveness

Faisal Feroz, Jonas R. Kunst

AI总结 本研究探讨了大型语言模型(LLM)在减少新闻偏见、提升跨党派接受度方面的潜力与局限。通过两项预注册实验,研究发现对自由派新闻标题进行实质性重述的干预措施,能够显著提升保守派读者的信任感和参与意愿,而对表面语言的轻微调整则无明显效果。研究还指出,尽管LLM在模拟环境中表现出一定的干预效果,但其对自身干预效果的评估存在量化不准确和心理真实性不足的问题,表明当前模型仍需人类监督以确保干预的有效性。

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英文摘要

Partisan news media erode cross-partisan trust, but large language models (LLMs) offer a potential means of debiasing such content at scale. Across two pre-registered experiments, we tested whether LLM-generated debiasing of liberal news headlines could improve conservative readers' trust-relevant judgments. Study 1 found that subtle lexical debiasing (replacing emotive words with more moderate synonyms) had no effect on any outcome. Study 2 found that a more substantive reframing intervention significantly increased conservatives' perceived trustworthiness, completeness, and willingness to engage with liberal news headlines, without producing a backfire effect among a sample of liberals. In Study 1, the intervention produced robust effects among LLM-simulated silicon participants, whereas it had no impact on human readers. In Study 2, the intervention's effects among silicon participants aligned directionally with human responses but were significantly larger in magnitude for some outcomes. Moderation analyses revealed that the model's implicit theory of who responds to debiasing diverged from the psychological profile that actually predicted human responsiveness. These findings demonstrate that LLM-based debiasing can improve cross-partisan receptivity when targeting ideological framing rather than surface-level language, but that current models lack both the quantitative accuracy and qualitative psychological fidelity to evaluate their own interventions without human oversight.

2605.00834 2026-05-11 cs.LG cs.CC cs.IT math.IT

Polynomial-Time Optimal Group Selection via the Double-Commutator Eigenvalue Problem

Mitchell A. Thornton

AI总结 该论文研究了在代数多样性框架下,如何高效地从高维观测中选择最优的群结构以匹配其协方差特性。传统方法需要指数时间枚举对称群的子群,而本文通过将问题转化为协方差矩阵的双交换子广义特征值问题,提出了一种多项式时间算法,能够在闭式中直接构造最优群生成元。该方法不仅计算高效,还提供了可验证的最优性保证,为群论、矩阵分析与统计估计之间建立了一种新的理论联系。

Comments v2: 2 theorems, 4 open problems, §X.A correction added; 1 reference added

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英文摘要

The algebraic diversity framework generalizes temporal averaging over multiple observations to algebraic group action on a single observation for second-order statistical estimation. The central open problem in this framework is $\textit{group selection}$: given an $M$-dimensional observation with unknown covariance structure, find the finite group whose spectral decomposition best matches the covariance. Naive enumeration of all subgroups of the symmetric group $S_M$ requires exponential time in $M$. We prove that this combinatorial problem reduces to a generalized eigenvalue problem derived from the double commutator of the covariance matrix, yielding a polynomial-time algorithm with complexity $O(d^2M^2 + d^3)$, where $d$ is the dimension of a generator basis. The minimum eigenvector of the double-commutator matrix directly constructs the optimal group generator in closed form, with no iterative optimization. The reduction is exact: the double-commutator minimum eigenvalue is zero if and only if the optimal generator lies in the span of the basis, and its magnitude provides a certifiable optimality gap when it does not. This problem does not appear in the standard catalogs of computational complexity (Garey and Johnson, 1979) and represents a new class linking group theory, matrix analysis, and statistical estimation. We establish connections to independent component analysis (JADE), structured matrix nearness problems, and simultaneous matrix diagonalization, and we show that the double-commutator formulation is the unique approach that is simultaneously polynomial-time, closed-form, and certifiable. We extend the framework to non-Abelian symmetry recovery via a Sequential GEVP with deflation, and add two identifiability theorems characterizing the commutant-lattice ambiguity and the dichotomy on whether $\mathrm{Aut}(\mathbf{R})$ recovers a generative subgroup or only a supergroup.

2605.00663 2026-05-11 cs.RO cs.CV

Affordance Agent Harness: Verification-Gated Skill Orchestration

Haojian Huang, Jiahao Shi, Yinchuan Li, Yingcong Chen

AI总结 该论文提出了一种名为“Affordance Agent Harness”的闭环运行系统,旨在解决开放世界场景中智能体交互区域识别的问题。该系统通过整合多种异构技能,结合经验记忆和成本控制机制,实现了对交互区域的可靠判定,并利用一个路由器动态选择和参数化技能。核心贡献在于引入了一个验证器,通过自一致性、跨尺度稳定性和证据充分性来判断是否可以做出交互决策,从而在保证推理效率的同时提升交互定位的准确性。

Comments 43 pages, 22 figures, 8 tables. Ongoing work

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英文摘要

Affordance grounding requires identifying where and how an agent should interact in open-world scenes, where actionable regions are often small, occluded, reflective, and visually ambiguous. Recent systems therefore combine multiple skills (e.g., detection, segmentation, interaction-imagination), yet most orchestrate them with fixed pipelines that are poorly matched to per-instance difficulty, offer limited targeted recovery from intermediate errors, and fail to reuse experience from recurring objects. These failures expose a systems problem: test-time grounding must acquire the right evidence, decide whether that evidence is reliable enough to commit, and do so under bounded inference cost without access to labels. We propose Affordance Agent Harness, a closed-loop runtime that unifies heterogeneous skills with an evidence store and cost control, retrieves episodic memories to provide priors for recurring categories, and employs a Router to adaptively select and parameterize skills. An affordance-specific Verifier then gates commitments using self-consistency, cross-scale stability, and evidence sufficiency, triggering targeted retries before a final judge fuses accumulated evidence and trajectories into the prediction. Experiments on multiple affordance benchmarks and difficulty-controlled subsets show a stronger accuracy-cost Pareto frontier than fixed-pipeline baselines, improving grounding quality while reducing average skill calls and latency. Project page: https://tenplusgood.github.io/a-harness-page/.

2605.00425 2026-05-11 cs.AI

AEM: Adaptive Entropy Modulation for Multi-Turn Agentic Reinforcement Learning

Haotian Zhao, Songlin Zhou, Yuxin Zhang, Stephen S. -T. Yau, Wenyu Zhang, Lun Tian, Tianshu Zhu, Yifeng Huang, Yucheng Zeng, Jingnan Gu, Daxiang Dong, Jianmin Wu

AI总结 本文提出了一种名为AEM的监督自由信用分配方法,用于多轮智能体强化学习,旨在解决稀疏奖励下难以分配信用的问题。AEM通过自适应调节熵动态,在探索与利用之间取得更好的平衡,其核心在于将熵动态从单个词元级别提升到完整响应级别,从而减少采样噪声的影响,并更准确地匹配大型语言模型的有效动作粒度。实验表明,AEM在多个基准任务上显著提升了强化学习基线的性能。

Comments 30 pages

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英文摘要

Reinforcement learning (RL) has substantially improved the ability of large language model (LLM) agents to interact with environments and solve multi-turn tasks. However, effective agentic RL remains challenging: sparse outcome-only rewards provide limited guidance for assigning credit to individual steps within long interaction trajectories. Existing approaches often introduce dense intermediate supervision, such as process reward models or auxiliary self-supervised signals, which increases supervision and tuning complexity and may limit generalization across tasks and domains. We present AEM, a supervision-free credit assignment method that adaptively modulates entropy dynamics during RL training to improve the exploration-exploitation trade-off. Since in agentic RL the environment is typically affected by a complete response, rather than an individual token, our analysis lifts entropy dynamics from the token level to the response level, aligning uncertainty estimation with the effective action granularity of LLM agents and reducing sensitivity to token-level sampling noise. We further show that entropy drift under natural-gradient updates is governed by the interaction between the sampled-response advantage and its relative surprisal. Motivated by this result, AEM derives a practical response-level uncertainty proxy and uses it to rescale advantages, leveraging the evolving balance between positive and negative samples to naturally transition from exploration to exploitation. Extensive experiments on ALFWorld, WebShop, and SWE-bench-Verified with models ranging from 1.5B to 32B demonstrate that AEM consistently improves strong RL baselines, including a +1.4\% gain when integrated into a state-of-the-art software-engineering RL training framework.