NeurIPS 2026 论文列表

Conference on Neural Information Processing Systems

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MSAR: Next-Scale Autoregressive Forecasting for Time Series via Modular Multi-Scale Decoupling

Fanda Fan, Kuiye Ding, Liming Mao, Wang Bingsong, Yao Wang, Xiaorui Wang, Ruijie Jian, Zhipeng Liu, Luqi Gong, Zhenghua Lu, Chunjie Luo, Jianfeng Zhan

展开摘要

Time series forecasting underpins critical applications in finance, energy, healthcare, and transportation. Although deep models have achieved strong results, most adopt single-scale modeling or restrict multiscale processing to the input side, causing a misalignment between multiscale inputs and single-scale outputs and limiting predictive power. We introduce the Modular Scale-wise Autoregressive Framework (MSAR), a model-agnostic design that forecasts progressively across multiple temporal resolutions. MSAR offers three advantages: (1) scale-wise aligned modeling, which disentangles heterogeneous temporal patterns by aligning inputs and outputs at each scale; (2) scale-wise autoregression, where coarse-scale predictions guide finer-scale forecasting through hierarchical information flow; and (3) a modular architecture, enabling seamless integration with diverse backbones such as CNNs, MLPs, and Transformers. Extensive experiments across a broad set of datasets and forecasting models demonstrate that MSAR achieves consistent improvements in both accuracy and inference efficiency, validating the effectiveness of scale-aligned autoregression for multiscale time series forecasting.

Poster
MMA-SafetyBench: A Benchmark for Multimodal Agent Safety Evaluation

Yuke Wang, Benlei Cui, Shen Pang, Xuemei Dong, Longtao Huang, Hui Xue&#x27, Yuwen Zhai, Junjie Li, Jingqun Tang, Haiwen Hong

展开摘要

As multimodal agents increasingly rely on visual perception to navigate complex digital workflows, the vulnerability of their reasoning-action cycles to cognitive manipulation has emerged as a critical security priority. This systemic reliance on visual-semantic grounding introduces a fundamental susceptibility to executive hijacking. Unlike traditional pixel-level adversarial noise, this threat operates at the cognitive-semantic level by synthesizing high-fidelity, deceptive UI elements—such as forged system alerts or mandatory compliance overlays—that seamlessly subvert an agent's safety alignment. We propose a targeted evaluation methodology that injects context-aware payloads into specific vulnerability windows within an agent's reasoning trace. By specifically changing the attack content within the observation space while strictly maintaining a static attack strategy, we demonstrate the consistent subversion of executive intent across diverse task trajectories. Building upon this, we introduce MMA-SafetyBench, the first comprehensive safety evaluation suite for multimodal agents. Comprising 1,083 adversarial trajectories, the benchmark evaluates these vulnerabilities across five ubiquitous environments: web automation, desktop/mobile OS control, visual document understanding, and long-form video reasoning. Our evaluation of nine state-of-the-art foundational models reveals a pervasive risk of executive hijacking, where agents disproportionately prioritize deceptive observations over benign textual constraints. With the Semantic Compromise Rate (SCR) reaching an alarming 98.09%, our findings expose a critical blind spot in current safety alignments and underscore the urgent need for cross-modal cognitive defenses in autonomous multimodal architectures.

Poster
MICE: Multi-animal Interaction Context Encoder — A Hierarchical Foundation Model for Mouse Behavior

Yen-Shuo Su, Weihan Li, Anqi Wu

展开摘要

Quantifying mouse behavior from pose is a foundational tool in neuroscience, ethology, drug discovery, and animal welfare. Self-supervised foundation models are a natural fit, but a foundation model for mouse behavior must handle social behavior - many behaviors that matter (aggression, courtship, mounting, allogrooming) are inherently multi-animal. Existing self-supervised pose models fall short: they encode each animal independently and discard interaction signal, hard-code the animal count, and pretrain one dataset at a time. We introduce MICE (Multi-animal Interaction Context Encoder), a hierarchical foundation model for mouse behavior that pretrains jointly on six mouse-pose corpora spanning one to four mice and 7 to 27 keypoints. MICE combines a hierarchical individual encoder capturing per-mouse kinematics at multiple temporal scales with a Perceiver-style social encoder whose learned latent codebook decouples parameter count from animal count, so a single checkpoint serves any group size without retraining. Across four evaluation protocols on all six datasets, MICE matches or exceeds prior keypoint-based baselines, and layer-wise probing shows the social stage incrementally improves discriminability beyond the individual encoder. Code and weights will be released.

Spotlight
MHWA: Multi-timescale Hierarchical World-Action Model

Pengcheng Pan, Guoqing Ma, Yuhan Zhang, Yang Chen, Yichen Liu, Ziheng Li, Shan Yu

展开摘要

Autoregressive world models have emerged as a powerful paradigm for sample-efficient decision-making, yet their open-loop rollouts often exhibit increasing drift that leads to error accumulation even within a relatively small planning horizon. Hierarchical temporal abstraction is a natural candidate to mitigate such drift by reducing the effective prediction horizon; however, existing hierarchical designs can introduce added structural and conceptual complexity, sometimes making them difficult to control and limiting gains over flat baselines. To this end, we introduce MHWA (Multi-timescale Hierarchical World Action model), which employs a strided high-level context channel to reduce global-context update frequency, effectively curbing the propagation of compounding drift. Crucially, via context-aware routing, the gating network dynamically reconfigures a Low-Level Mixture-of-Experts by using both global context and current observations, thereby enabling flexible high--low coordination, helping alleviate interference commonly observed in static hierarchies. Empirically, MHWA (77M parameters) achieves an IQM human normalized score (HNS) of 0.867$\pm$0.047 across three training seeds on a 14-game Atari subset using 10\% subsampled offline data, matching the existing state-of-the-art 150M-parameter JOWA baseline while using nearly half the parameters and significantly reducing computational costs.

Poster
MGMem: An Efficient, Deterministic, and Provenance-Preserving Framework for Long-Horizon Agent Memory

Junhong Huang, Xin Tong, Jun Xia

展开摘要

Long-horizon Large Language Model (LLM) agents need persistent memory that surfaces the right past interaction at the right time across thousands of turns. Current systems index by invoking generative LLMs to rewrite history into summaries, facts, or knowledge graphs---a step that is (a) costly (up to $\sim 50$K LLM calls and $35.83$M completion tokens per build), (b) non-deterministic (undermining reproducibility and giving inconsistent answers across runs), and (c) provenance-erasing (the reader sees synthesized text, not the original turn). We propose MGMem, an LLM-call-free framework that replaces this step with a deterministic discriminative-parser pipeline: recurring mentions across sessions are organized into an incidence graph, question mentions are resolved by a subject-conditioned three-stage resolver, and raw dialogue episodes are returned to the reader. On LoCoMo, MGMem outperforms matched-protocol generated-memory and retrieval baselines at zero generative indexing calls; on the full LongMemEval-S, it remains competitive overall and leads on single-session question types. Anonymous code: \url{https://anonymous.4open.science/r/mentiongraph}.

Poster
MEME: Multi-Entity & Evolving Memory Evaluation

Seokwon Jung, Alexander Rubinstein, Arnas Uselis, Sangdoo Yun, Seong Joon Oh

展开摘要

LLM-based agents increasingly operate in persistent environments where they must store, update, and reason over information across many sessions. While prior benchmarks evaluate only single-entity updates, MEME defines six tasks spanning the full space defined by the multi-entity and evolving axes, including three not scored by prior work: Cascade and Absence (dependency reasoning) and Deletion (post-removal state). Evaluating six memory systems spanning three memory paradigms on 100 controlled episodes, we find that all systems collapse on dependency reasoning under the default configuration (Cascade: 3\%, Absence: 1\% in average accuracy) despite adequate static retrieval performance. Prompt optimization, deeper retrieval, reduced filler noise, and most stronger LLMs fail to close this gap. Only a file-based agent paired with Claude Opus 4.7 partially closes the gap, but at $\sim$70$\times$ the baseline cost, indicating closure currently depends on configurations that are not practical at scale. Code is available at https://anonymous.4open.science/r/MEME-0612 and the dataset at https://huggingface.co/datasets/meme-benchmark/MEME.

Poster
MCAS: Signal-Processing-Based Multi-View Contrastive Learning for Acoustic Sensing

Bingzhi Wang, Jiajun Yu, Dengke Zhong, Jiaming Liu, Xiong Li, Hongbo Liu, Jie Yang

展开摘要

Acoustic sensing is a promising technique for human-computer interaction, but existing learning-based systems still depend heavily on large task-specific labeled datasets. Compared with visual data, acoustic signals are difficult to interpret and annotate, making supervision costly and hard to scale. Meanwhile, existing unsupervised representation learning methods, particularly contrastive learning, are largely designed for natural images and rely on data augmentation to form positive pairs. Such strategies can destroy the temporal-physical structure of acoustic signals, causing shortcut learning rather than meaningful representation learning. To address this issue, we propose MCAS, a signal-processing-based multi-view contrastive learning framework for acoustic sensing. Instead of relying on artificial augmentations, MCAS constructs structure-preserving positive pairs from complementary representations derived from different signal processing pipelines of the same acoustic event. Moreover, MCAS is designed to address the heterogeneity of acoustic representations through progressive cross-view interaction enabled by Hierarchical Shared-Token Fusion and a multi-level pretraining objective with physical consistency regularization. Extensive experiments on two typical acoustic sensing tasks demonstrate the effectiveness of the proposed framework. Under low-label settings, MCAS consistently outperforms both supervised baselines and generic self-supervised baselines, while also showing strong cross-task transferability and robustness to corruptions and noise.

Poster
MC-H: Multi-Granularity Clustering with Hyperspherical Determinantal Point Process

Yingjie Ge, Kun Zhou, Jieyu Zhao, Xulun Ye

展开摘要

Deep clustering struggles when coarse-grained and fine-grained semantics coexist in the same dataset, as a unified partitioning strategy tends to either over-separate coarse categories or miss subtle fine-grained differences. To address this problem, we propose the adaptive multi-granularity clustering framework in a hyperspherical space (MC-H). The framework combines Dynamic Prototype-Center Assignment (DPCA), a Hyperspherical Determinantal Point Process (H-DPP) module that adaptively regulates repulsion according to local structure and promotes stronger separation in dense regions while preserving flexibility in sparse ones, and a Semantic Subspace Denoising (SSD) module that suppresses non-semantic variations and improves cluster compactness. Extensive experiments across datasets with different semantic granularities show that our method consistently outperforms existing approaches and effectively unifies clustering across the full granularity spectrum.

Poster
MC$^2$Mark: Distortion-Free Multi-Bit Watermarking for Long Messages

Xuehao Cui, Ruibo Chen, Yihan Wu, Weidong Cai, Heng Huang

展开摘要

Large language models now produce text indistinguishable from human writing, which increases the need for reliable provenance tracing. Multi-bit watermarking can embed identifiers into generated text, but existing methods struggle to keep both text quality and watermark strength while carrying long messages. We propose MC$^2$Mark, a distortion-free multi-bit watermarking framework designed for reliable embedding and decoding of long messages. Our key technical idea is Multi-Channel Colored Reweighting, which encodes bits through structured token reweighting while keeping the token distribution unbiased, together with Multi-Layer Sequential Reweighting to strengthen the watermark signal and an evidence-accumulation detector for message recovery. Experiments show that MC$^2$Mark improves detectability and robustness over prior multi-bit watermarking methods while preserving generation quality, achieving near-perfect accuracy for short messages and exceeding the second-best method by nearly 30% for long messages.

Poster
MASTARS: Multi-Agent Sequential Trajectory Augmentation with Return-Conditioned Subgoals

Jiwon Jeon, Myungsik Cho, Woojun Kim, Seongmin Kim, Woohyeon Byeon, Seungyul Han, Youngchul Sung

展开摘要

The performance of offline Multi-Agent Reinforcement Learning (MARL) is limited by the quality of the fixed offline dataset, motivating trajectory augmentation. However, augmenting multi-agent trajectories presents a fundamental challenge of the diversity–coordination trade-off: independent generation improves diversity but lacks coordination, while joint generation induces coordination but lacks diversity, reproducing the training distribution. To address this challenge in multi-agent data augmentation, we introduce MASTARS, a novel diffusion-based framework that generates multi-agent trajectories sequentially across agents while enforcing cross-agent consistent coordination via the method of inpainting. MASTARS produces trajectories that are diverse, coordinated and globally coherent. Experiments on various benchmarks such as MPE, SMAC, and SMAC-v2 demonstrate significant performance gains across multiple offline MARL methods.

Poster
MARBLE: an Agent Benchmark for Spatial Reasoning and Visual Abstraction

Yulun Jiang, Naël Ouerghemi, Yekun Chai, Maria Brbic, Michael Moor

展开摘要

A central challenge for multimodal language models (MLLMs) in real-world tasks is to abstract visual observations into structured spatial states and reason over how those states change under actions over long-horizons. Existing multimodal benchmarks often focus on static question answering, where answers can be directly extracted from images, or assume symbolic states are available and bypass the visual-to-spatial abstraction process. We present MARBLE, a diagnostic benchmark for spatially grounded multimodal reasoning and planning across three agent environments: Cube, Maze and Blox. MARBLE spans 2D and 3D spatial puzzles under geometric constraints, dynamic layouts, and spatial transformations, with difficulty systematically controlled along two axes: observation format and planning horizon. Extensive evaluations show that frontier MLLMs struggle on MARBLE, with the strongest model GPT-5.4 achieving only a 7.3\% average success rate across the three environments in the hardest setting. Pairwise ablations on the open-weight models identify visual-to-spatial abstraction as the major bottleneck: when models must infer spatial states from images instead of receiving human-annotated states, success drops from 50.7\% to 3.7\% for Gemma-4-31B and from 87.9\% to 6.5\% for Kimi-K2.6. The results indicate that models often fail to construct precise spatial states from visual observations before planning, a task that is straightfoward for human. Overall, MARBLE reveals the gap of reliable visual-to-spatial for frontier MLLMs and provides a controlled testbed for measuring progress in spatially grounded multimodal reasoning and planning.

Poster
MANGO:Multi-Angle Neural Gated Operators for Chirp-Perturbed PDEs

Yunlong Zhu, Zunwei Fu, Zheng Wang, EUN-HU KIM

展开摘要

We introduce **MANGO** (Multi-Angle Neural Gated Operator), a spectral neural operator for chirp-perturbed PDEs whose solutions exhibit a local spectral content that rotates continuously with position. MANGO maintains multiple fractional Fourier transform (FRFT) branches whose angles are learnable parameters, optimized jointly with the spectral weights and a position-dependent softmax gate that combines branches at every spatial location. The architecture is matched to the structure of the problem class: the FRFT at angle $\alpha_0$ diagonalizes the chirp-perturbed PDE whose intrinsic angle is $\alpha_0$, and MANGO's learnable angles let the architecture discover $\alpha_0$ from data when it is unknown or varies across the domain—neither of which classical FRFT methods accommodate. We further introduce a Mihlin–Hörmander regularizer on the spectral weights of each non-Fourier branch, encouraging each branch to act as a bounded operator on $L^p$ for $1 < p < \infty$. We construct four chirp-perturbed PDE benchmarks with closed-form ground truth, positioned as identifiability tests. On these benchmarks, MANGO recovers the intrinsic spectral structure of each PDE from supervised solution data alone and achieves state-of-the-art performance against six neural-operator baselines.

Poster
MAGE: Towards Generalizable Multi-timescale EEG Representations

Tuan Kiet Doan, Van Chien Nguyen, Trung-Hieu Tran, Quang Hung Pham, Ngoc-Son Vu, Huy Phan, Phi Le Nguyen, Duc-Han LE, Nikola Simidjievski, Van-Tam Nguyen

展开摘要

Electroencephalography (EEG) data plays an important role in understanding human brain activity, with various major applications. While current approaches, which largely build on EEG foundation models, have demonstrated strong performance across datasets and tasks, they typically rely on a fixed temporal scale. This design choice limits their ability to capture characteristics of neural dynamic behavior, often spanning across multiple timescales, which are naturally captured in EEG recordings. To address this limitation, we propose MAGE (**Multi-timescale Adaptive Generalization for EEG**), a foundation model that dynamically adapts to capture and integrate information across different timescales. Specifically, MAGE combines two key mechanisms: (i) a novel multi-timescale attention mechanism, capable of learning representations across multiple temporal scales, and (ii) a trainable aggregation module that dynamically identifies and adapts to the most informative timescale of the input signal. Experimental results across seven datasets demonstrate that MAGE consistently outperforms existing EEG foundation models while using substantially fewer parameters. Moreover, our results support the hypothesis that different downstream tasks benefit from distinct temporal scales. All source code will be released.

Poster
MACRO: Training-free Multi-plane Attention for Closeup Render Optimization

Nitzan Hodos, Roy Amoyal, Lior Fritz, Ianir Ideses, Sagie Benaim, Netalee Efrat

展开摘要

Close-up rendering, zooming into a scene well beyond any training camera, is important for virtual production and interactive 3D content, yet remains an open challenge. 3D Gaussian splatting (3DGS) enables high-fidelity, real-time novel view synthesis, but its rendering quality degrades at close range. Recent diffusion-based methods that enhance the rendering by conditioning on reference images from the training set produce significant artifacts in this setting. We analyze this failure and identify its root cause: the scale gap between the close-up and reference views. We show that the features in reference-conditioned enhancement models are not scale-invariant, causing cross-view attention to retrieve incorrect correspondences when the same content appears at different scales, and that this mismatch cannot be corrected in latent space because the VAE encoder is not scale-equivariant. Building on this analysis we introduce MACRO, Multi-plane Attention for Closeup Render Optimization, a training-free method for high-quality close-up novel view synthesis from 3DGS. MACRO resolves the scale gap by leveraging the scene's known 3D structure: it decomposes the close-up into depth planes, crops and resizes references in image space to match the scale of each plane before encoding, and applies a depth-aware attention mask so each token attends only to scale-matched references. The method requires no architectural changes or additional training. We further contribute two new close-up novel view synthesis benchmarks, the first standardized evaluation protocol for this setting, and demonstrate state-of-the-art results on both, outperforming existing 3DGS and diffusion-based methods on both reconstruction and perceptual metrics.

Spotlight
LongMINT: Evaluating Memory under Multi-Target Interference in Long-Horizon Agent Systems

Hyunji Lee, Justin Chen, Joykirat Singh, Zaid Khan, Elias Stengel-Eskin, Mohit Bansal

展开摘要

Agents in real-world settings operate over long and evolving horizons, where information is repeatedly updated and can interfere with each other across memories, requiring accurate recall and aggregated reasoning over multiple pieces of information. However, existing benchmarks focus on static, independent recall and fail to capture these dynamic interactions between evolving memories. In this paper, we study how current systems perform in realistic, continuously evolving, long-horizon settings across diverse domains and question types. To this end, we construct an analytical benchmark, LongMINT (Long-Horizon Memory under INTerference), which features (1) long, highly interconnected contexts with frequently updated information, (2) diverse coverage across multiple memory domains (Wikipedia, code, multi-turn dialogue, and state tracking), enabling evaluation of domain generalization, and (3) diverse question types, including (i) single-target recall tasks that test retrieval under interference over long contexts and (ii) multi-target aggregation tasks that require counting, ordering, or reasoning across multiple relevant pieces of information. We evaluate over six representative systems, including vanilla long-context LLMs, retrieval-augmented generation methods, and memory-augmented agent frameworks. We observe consistently low performance (avg. 27.7\% accuracy), especially on questions that require aggregated reasoning over multiple pieces of evidence. Fine-grained analysis shows that performance is primarily limited by retrieval and memory construction capabilities. Furthermore, current memory systems struggle to recall and reason over facts that are multiple steps back, and performance decreases when this lookback distance increases. These findings highlight the need for more robust memory management systems for dynamic, long-horizon environments across varying domains.

Poster
LogSig-SSM: Time-Series Modelling with Multi-Scale Log-Signature Compression for State-Space Models

Felix Oury, Nicolas Calvo Peiro, Reiko J Tanaka

展开摘要

Time-series data are often sampled irregularly at high frequency and exhibit long-range dependencies, which makes long-horizon modelling difficult. Continuous-time models such as neural controlled differential equations (NCDEs) and neural rough differential equations (NRDEs) can handle irregular sampling, but they scale poorly to long sequences. Selective state-space models (SSMs) such as Mamba scale linearly with sequence length, but within a single block they provide limited recurrent mixing across hidden dimensions. We propose LogSig-SSM (Log-Signature Compression for State-Space Models), which first compresses long multivariate time series into a shorter sequence of tokens using multi-scale windowed log-signatures, and then processes these tokens with a selective SSM backbone. LogSig-SSM is scalable and robust to irregular sampling, combining log-signature tokens that capture higher-order cross-channel interactions with a selective SSM that models long-range dependencies. The model also admits a continuous-time interpretation as an NCDE/NRDE-style system driven by a log-signature-based input, in which selectivity induces an input-dependent rescaling of the latent dynamics. Across four benchmarks, namely long-sequence classification on UEA, high-frequency physiological regression on PPG-DaLiA, multivariate weather forecasting, and irregularly sampled clinical prediction on PhysioNet Sepsis, LogSig-SSM overall outperforms existing SSM and continuous-time baselines while significantly reducing training time and GPU memory usage.

Poster
LoRASpace: A Pool-Wide Shared Substrate for Static and Dynamic Multi-LoRA Composition

Thamirawaran Sathiyalogeswaran, Navindu De Silva, Chamikara Siriwardane, W K Alwis, Jason Mars, Udaya S Thanthrige, Ranga Rodrigo

展开摘要

Low-rank adaptation (LoRA) attaches small low-rank matrices to a frozen backbone, and public repositories like Hugging Face host many such LoRAs per backbone, each for a different concept, character, style, or task. Users routinely want to combine several LoRAs in a single generation, but two existing strategies involve a trade-off with each other. First, combining the LoRA weights into a single update before inference (e.g., static merge) needs only one forward pass, but quality drops, because LoRAs trained for different concepts interfere when their weights are summed into a single update, distorting each LoRA's contribution. Second, running each LoRA in a separate forward pass and summing the outputs (e.g., composite) preserves output quality, but each LoRA adds a full backbone pass, so inference time scales linearly with the active LoRA count. To recover composite-level quality at merge cost, we study a property of LoRA pools overlooked by prior multi-LoRA work. When LoRAs in a pool are trained on related concepts, their low-rank factors overlap substantially. Using singular value decomposition, we find the minimal subspace that preserves 99% of the factor energy. On three diffusion pools, only 46% to 57% of the sum of individual LoRA ranks is enough to represent the pool, and the subspace grows sub-linearly with pool size. A 48-LoRA sub-pool of LoRA-Hub on FLAN-T5 NLP tasks shows comparable overlap (about 62%), while the diversity-curated LoRA-Retriever benchmark sits near the no-overlap baseline at 96%, indicating that across these five pools pool composition rather than modality predicts where overlap is large. We use this overlap to construct LoRASpace, a training-free pool-wide method where the subspace matrices are computed once per pool and reused across two inference modes: a static mode at merge inference cost, and a dynamic mode for input-dependent routing at substantially lower cost than composite. On the diffusion pools, static LoRASpace matches composite quality at merge cost, and dynamic LoRASpace achieves more than 6× speedup over composite at six active LoRAs on a 17-LoRA pool. In our ablation, we show that the quality gain comes from truncating to this low-rank shared subspace, which acts as a form of regularisation. On the near-orthogonal LoRA-Retriever benchmark, the framework predicts limited compression benefit, with gains coming from external retrieval coupling.

Poster
Learning in Causal Markov Games

Aurghya Maiti, Elias Bareinboim

展开摘要

Markov Games are the standard formal model for multi-agent reinforcement learning, capturing agents that act in a shared state and optimize rewards over time. However, in real-world settings, agents’ decisions are often influenced by unobserved factors, such as cognitive biases, behavioral tendencies, or intuitive signals, that also affect rewards and future states. Ignoring these unobserved confounders can make standard learning methods converge to suboptimal policies. In such settings, optimal play may require policies that condition on counterfactual signals, requiring reasoning at the counterfactual layer of the Pearl Causal Hierarchy. In this paper, we introduce Causal Markov Games (CMGs), a framework for modeling sequential multi-agent decision making in the presence of unobserved confounding. We show that CMGs strictly generalize Markov Games, with arbitrarily large gaps between classical interventional equilibria and causal counterparts. We then develop two learning algorithms under different observability assumptions. The first, CNash-VI-FO, is a model-based learner with finite-sample guarantees when agents’ natural actions or intuitions are revealed post hoc. The second, CNash-VI-NO, is an explore-then-exploit procedure with asymptotic guarantees for the setting in which opponents’ natural actions are never observed. To address scalability, we further provide a drop-in counterfactual augmentation of deep MARL. Empirically, on a confounded windy variant of the Multi-Particle Environment and the Iterated Causal Prisoner’s Dilemma, counterfactual agents strictly dominate their non-causal counterparts.

Poster
Learning When to Collaborate: Selective Multi-Agent Medical Reasoning via Uncertainty-Aware Routing

Jiacheng Hou, Xueliang Cui, Dan Lu, Ruxin Wang

展开摘要

Multi-agent systems have emerged as a promising paradigm for multimodal medical reasoning, but existing methods rely on two assumptions that hinder practical deployment: (i) always-active dense collaboration among multiple agents, and (ii) dependence on large cloud-based models that raise privacy and efficiency concerns. In this paper, we challenge both assumptions and propose SMART-Med, a fully local multi-agent method that treats collaboration as a learnable decision rather than a default behavior. Our key insight is that not every medical query requires costly multi-agent deliberation: many can be reliably solved by a single well-trained agent, while only uncertain cases benefit from expert collaboration. Based on this insight, SMART-Med introduces an uncertainty-driven routing mechanism that adaptively decides when to answer directly and when to recruit a small subset of expert agents, effectively converting dense multi-agent reasoning into selective, query-adaptive coordination. To make this routing reliable, we curate a new multimodal medical dataset MedVR-3K with high-quality reasoning traces and a difficulty hierarchy, and then fine-tune local agents using GRPO with two complementary rewards: a certainty-aware accuracy reward and a vision-language reward model for correctness and reasoning quality respectively. Experiments on four medical visual question answering benchmarks show that SMART-Med achieves competitive performance compared to existing MAS approaches while substantially reducing inference cost (reducing inference time by more than 3.8$\times$ and token usage by 72\%). Moreover, after fine-tuning on MedVR-3K, SMART-Med yields an average improvement of 6.7\% across Slake, PathVQA, VQA-RAD, and PMC-VQA. Our results suggest that selective collaboration can be an efficient yet effective alternative to dense collaboration and enable practical, privacy-preserving deployment of multi-agent medical AI.

Poster
Learning Orthogonal Multi-Index Models Beyond Small Initialization: Incremental Learning, Competitive Dynamics and Symmetry

Mo Zhou, Weihang Xu, Simon Du, Maryam Fazel

展开摘要

Recent work has identified incremental learning in shallow networks trained on single-index and multi-index models. However, existing analyses often rely on simplifying settings, such as small initialization, correlation loss, or layer-wise training. These choices reduce neuron interactions and leave some feature learning dynamics under standard initialization unexplored. We study gradient flow dynamics for polynomial-width two-layer networks learning orthogonal multi-index targets under standard initialization using polynomially many samples. We first prove that incremental learning still occurs: the loss decreases sequentially according to the Hermite expansion of the target, with lower-order components learned before higher-order components recover the individual target directions. In this standard initialization regime, training also shows a competitive reallocation of parameter mass: after the total mass fits the target mean and stabilizes, mass shifts into the target subspace and then concentrates on aligned neurons. Technically, we introduce a symmetry-based finite-width approximation via symmetrized networks, rather than comparing directly with an infinite-width limit. This yields better control of approximation errors and may be of independent interest.

Poster