NeurIPS 2026 论文列表

Current 4D occupancy world models use heavy cross-attention or deep recurrence to disentangle ego-motion from scene dynamics. This requires significant computational capacity. However, this effort is largely redundant since ego-motion is inherently known from odometry. We present FreeOcc, a lightweight continuous-time world model that introduces explicit $SE(2)$ geometric decoupling into a conditional flow-matching framework. By mathematically factoring out self-motion, we create a purely dynamic feature space. This space supports attention-free temporal fusion and allows physics-constrained ODEs to operate strictly on residual agent kinematics. To maximize deployment efficiency, FreeOcc introduces an uncertainty-aware blending mechanism. This routes well-observed voxels to a single-pass decoder, reserving the ODE solver exclusively for ambiguous, high-uncertainty regions. Requiring only 28.3M parameters—roughly 40\% of comparable models—our optimal ensemble mode (FreeOcc-E) runs at 27 FPS. On nuScenes, FreeOcc achieves state-of-the-art forecasting performance with a 0.47 m Near Field Chamfer Distance (NFCD) and 32.1\% mIoU. Furthermore, the model transfers zero-shot to SemanticKITTI. It also proves highly robust, retaining 92.8\% of its ideal mIoU under significant sensor packet loss and timestamp jitter.

Adapting pretrained Vision-Language-Action (VLA) policies to new deployment environments typically requires collecting expert demonstrations in each target domain, which is costly and difficult to scale. In this paper, we present FreeAct, a framework for demonstration-free robot adaptation that converts generated videos into physically grounded supervision. However, a key challenge is that generated manipulation videos, while visually plausible, often contain embodiment artifacts and kinematic inconsistencies that make direct inverse-dynamics labeling unreliable. FreeAct addresses this challenge by learning a discrete latent action space from large-scale multi-lab robot videos and aligning it with camera-frame end-effector SE(3) motion and gripper-state changes. The resulting latent action tokenizer captures task-relevant motion while reducing reliance on embodiment-specific visual artifacts, enabling generated target-domain videos to be pseudo-labeled with reliable latent action tokens. These tokens are first injected into VLA pretraining and then used, together with source-domain action supervision, to adapt the policy to unseen environments. Empirically, FreeAct improves success from 2\% to 57\% under target-domain shift using generated videos alone, and further to 74\% through MLLM-guided self-evolution on the policy's own rollouts, closing the adaptation loop without expert demonstrations. Further analysis shows that the learned latent action space forms a kinematically structured and transferable representation, establishing generated videos as a scalable source of supervision for robot manipulation.

Free energy estimation is a fundamental yet challenging problem, from physics to statistics. Classical approaches rely on thermodynamic transformations, ranging from direct estimation, quasistatic integration, to finite-time averaging. Recent work learns neural transports to significantly accelerate the efficiency in the finite-time regime. In this paper, we generalize this framework to arbitrary state spaces. Building on this view, we develop a generalized neural transport learning approach for efficient estimation. Experiments validate the effectiveness and efficiency of the proposed method beyond continuous settings, extending to discrete and multimodal spaces as well as autoregressive settings.

Diffusion Large Language Models (dLLMs) have emerged as a compelling paradigm for language modeling, offering the unique potential for highly efficient inference via multi-token parallel decoding. However, unlocking this potential remains challenging. High-quality generation typically defaults to one-token-per-step static decoding, while existing parallel algorithms rely on heuristic confidence thresholds, introducing a fragile trade-off between decoding efficiency and generation quality. To overcome this, we introduce **Free** **D**raft-**a**nd-**Ve**rification (**FreeDave**), a novel training-free and model-free fast decoding algorithm. FreeDave capitalizes on the inherent properties of dLLMs by treating future token predictions as "free drafts" and rigorously self-verifying them in subsequent forward passes. Theoretically, FreeDave is guaranteed to use the fewest possible model forward passes to reproduce the exact sequence generated by static decoding, achieving algorithmically lossless acceleration. Extensive evaluations on math reasoning and code generation benchmarks demonstrate that FreeDave can boost the number of generated tokens per model forward (TPF) by up to 5.48$\times$ and tokens per second (TPS) by up to 3.94$\times$, while robustly maintaining generation quality and avoiding the task-specific performance degradation faced by heuristic methods.

Tools from random matrix theory have become central to deep learning theory, using spectral information to provide mechanisms for modeling generalization, robustness, scaling, and failure modes. While often capable of modeling empirical behavior, practical computations are limited by matrix size, often imposing a restriction to models that are too small to be realistic. This motivates the inference of properties of larger models from the behavior of smaller ones. Free decompression (FD) is a recently proposed method for extrapolating spectral information across matrix sizes, but its utility is currently limited by strong assumptions that preclude its implementation on more realistic machine learning (ML) models. We use algebraic spectral curve theory to provide a general FD methodology for spectral densities whose Stieltjes transform satisfies an algebraic relation, a modeling assumption that is more likely to hold in practice. This recasts FD as an evolution along spectral curves which can be readily integrated. Our framework enables the expansion of spectral densities that have multiple or multi-modal bulks, that exist at multiple scales, and that contain atoms, all characteristic of real-world data and popular ML models. We demonstrate the efficacy of our framework on models of interest in modern ML, including Hessian and activation matrices associated with neural networks and large-scale diffusion models.

Fine-tuning large-scale foundation models across resource-constrained, distributed clients presents significant computational and communication challenges. While merging Low-Rank Adaptation (LoRA) with Federated Learning (FL) enables rank-based flexibility, the interdependence of the adaptation matrices ($A$ and $B$) often complicates optimization. In this work, we theoretically demonstrate that LoRA fine-tuning with a frozen A matrix acts as a stochastic approximation of full fine-tuning, where batch gradients are subject to a random, rank-dependent perturbation. Motivated by this insight, we propose freezing and periodically resampling $A$ matrices at the client level. This strategy decouples the $A$ and $B$ gradients, diminishes LoRA low-rank constraints and reduces both computational and uplink communication overheads by 50%, allowing for the reallocation of resources toward higher adaptation ranks. Furthermore, we show that in this frozen-$A$ regime, the adaptation rank $r$ directly governs the signal-to-noise ratio (SNR) of the perturbed gradients. Specifically, we find that the SNR increases linearly with $r$, implying that clients’ learning rates must be dynamically scaled with their adaptation ranks for higher utility. Building on these foundations, we introduce Frank-LoRA, a federated rank-aware fine-tuning strategy that utilizes frozen, resampled $A$ matrices and rank-dependent learning rates for clients. We also prove the convergence of the algorithm in FL settings with heterogeneous clients resources. Our experiments across benchmark datasets demonstrate that Frank-LoRA consistently outperforms state-of-the-art baselines with half the overhead on clients.

Streaming Visual Geometry Transformers such as StreamVGGT enable strong online 3D perception, but their KV-cache grows unbounded over long streams, limiting practical deployment. We study bounded-memory streaming geometry from the perspective of memory organization: unlike language modeling, where useful information can often be compressed at token level, geometry-driven inference relies on coherent and mutually compatible observations across views. Under fixed memory budgets, retaining history as isolated entries can progressively fragment the geometric context needed for stable long-horizon matching and fusion. We therefore propose \textbf{FrameVGGT}, a bounded-memory framework that maintains a fixed-capacity set of complementary memory units for streaming geometry. In our implementation, each unit is instantiated as a frame-wise KV segment summarized by a compact key-space prototype, together with a sparse anchor tier for persistent long-range references. Across long-sequence 3D reconstruction, video depth estimation, and camera pose estimation, FrameVGGT achieves favorable accuracy--memory trade-offs under bounded budgets while maintaining more stable geometry over long streams.

Frame selection---picking a small set of informative frames from a video to feed a vision-language model (VLM)---sits at the front of every video-VLM system, yet the literature is fragmented: most works do not share a candidate pool, encoder, frame budget, or answering VLM, making published gains hard to compare across works. We introduce FrameSelect, to the best of our knowledge the first Python library that treats the selector as a standalone, interchangeable component, cleanly separated from the encoder that computes representations and the VLM that answers. Any registered selector composes with any registered evaluator through a single call, and adding a new selector, dataset, encoder, or VLM backend is an isolated extension; a replay mode further rebuilds any table under a different answering VLM without re-running selection. We release reference implementations of 20 selectors, 15 evaluators spanning answer-level and selection-level metrics, and the first unified benchmark comparing frame selectors under a shared protocol across seven evaluators spanning both evaluation modes. This comparison surfaces findings that existing studies cannot: rankings invert across benchmarks. Our library is available at https://anonymous.4open.science/r/FrameSelect-D2A4.

Long video understanding requires VideoLLMs to answer queries about videos spanning tens of minutes to hours, but such long videos produce far more visual tokens than current VideoLLMs can process. To address this issue, keyframe selectors are proposed to select the most query-relevant frames by computing the similarity between frame and query embeddings. Existing selectors either encode frames independently without temporal context or process chunks in isolation with ranking objectives that are difficult to optimize. To alleviate those limitations, we propose FrameScout with two core designs: (i) a streaming selector architecture that leverages a sliding-window KV cache and successor aggregation to produce temporally-contextualized frame embeddings; (ii) a frame-query contrastive objective that aligns frame and query embeddings in a shared space, directly training the selector to distinguish relevant frames from irrelevant ones. Extensive experiments on three long-video benchmarks and six base VideoLLMs demonstrate that FrameScout consistently achieves state-of-the-art performance.

Long-video question answering benchmarks like Video-MME-v2 typically evaluate systems under a uniform frame budget for every question, despite stark variation in the evidence each query actually demands. We analyze this mismatch on Video-MME-v2 and find that different question subsets prefer different frozen frame-budget policies, while uniformly increasing the frame count does not reliably improve all metrics. These findings motivate fixed-mean frame-budget routing, a controlled inference setting in which each question may receive a different frame budget while the average budget matches a uniform reference. We introduce FrameRouter, a training-free test-time framework that combines an evidence-demand router, a budget-constrained allocation rule, and a frozen bank of frame-sampling policies. By controlling how much visual evidence each question receives while leaving the underlying samplers unchanged, FrameRouter is orthogonal to query-aware frame selection. Across Video-MME-v2 and several long-video understanding benchmarks, FrameRouter improves long-video question answering by using the same average visual budget more selectively across questions.

State Space Models (SSMs) compress sequence history into a bounded recurrent state, making the resulting memory law a central architectural choice for long-context performance. Most modern SSMs rely on ODE-based dynamics that lead to exponential forgetting, limiting their ability to retain information over broad temporal ranges. We introduce FRAC, a selective SSM architecture derived from fractional dynamics that replaces this exponential decay with power-law long memory. To make fractional dynamics practical, FRAC approximates the heavy-tailed target kernel with a finite-state, log-spaced sum of exponential modes. This construction turns fractional memory into an efficient recurrent module with parallel training and prefill, while retaining bounded-state autoregressive decoding. Extensive experiments, including 1.3B-parameter language modeling, demonstrate that FRAC consistently improves long-context performance over state-of-the-art SSM baselines while staying competitive on short-context. These results show that fractional dynamics provide a practical and effective prior for long-context SSMs.

Medical image segmentation requires the precise alignment of macroscopic semantics and microscopic geometry, yet existing representation paradigms struggle to balance massive low-frequency semantic context with ultra-sparse, high-frequency boundary details. To address this fundamental information asymmetry, we introduce Fractal-G, a plug-and-play multi-scale fusion module that presents a continuous Grid-Graph-Grid feature reconstruction paradigm. Within this framework, an Uncertainty-Aware Fission Router dynamically translates regular image grids into a non-uniform heterogeneous graph, adaptively allocating dense microscopic nodes to complex boundaries while retaining sparse macroscopic nodes in homogeneous background regions. To ensure unbiased feature aggregation across these varying physical scales, an Area-Aware Continuous Neighborhood Graph explicitly incorporates physical node sizes into the topological message passing. Finally, a Topology-Aware Implicit Renderer projects the unstructured graph back into dense, artifact-free continuous feature fields. Extensive experiments on diverse medical image segmentation tasks (including skin lesions and polyps) demonstrate that Fractal-G easily integrable with mainstream backbones, consistently achieving state-of-the-art geometric fidelity and cross-resolution robustness with only 12\% GFLOPs increase (U-Net based). Our code is publicly available at https://anonymous.4open.science/r/Fractal-G/.

Time series are ubiquitous across different domains, and the growing use of synthetic data for privacy-preserving sharing, data augmentation, and stress testing makes time series generation increasingly important. Early generative approaches are predominantly autoregressive, which can suffer from low sample diversity, error accumulation, and difficulty modeling long-range dependencies. In this paper, we introduce FracTS, a hierarchical, coarse-to-fine autoregressive model for multi-variate time series generation. Inspired by fractal generative modeling developed for images, FracTS adapts the paradigm from 2D to 1D sequences by learning a multi-scale representation that captures global trajectory structure at coarse scales and local dynamics at fine scales while following the autoregressive nature of time series. In contrast to unstructured images, time series are structured, allowing easy automated or designated temporal feature processing optimized for the model, and global (static) features extraction describing the instances that generate the corresponding time series in the collection. We incorporate them in the generation process to further improve the generation quality. The design naturally handles multivariate dependencies and improves long-horizon temporal coherence without requiring fixed-length inputs. Experiments on five datasets (two conditional, three unconditional) conducted against seven baselines show that FracTS consistently outperforms baselines across marginal distribution, correlation preservation, and ML utility. In particular, the ML utility is improved up to 98.1% comparing to the second-best baseline. Code is available at: https://anonymous.4open.science/r/fracts-91D621

In real-world tasks such as robotic control and autonomous driving, agents often face non-Markovian environments due to incomplete observations. Solving such information-impoverished decision tasks requires reconstructing the context from history. However, existing recurrent encoders have two fundamental limitations: First, the model suffers from a Markovian compression bottleneck, i.e., it only processes observation history as input but neglects thought process history. This leads to the loss of deep semantic cues from early interactions, which are easily overwritten by noise over time due to recursion. Second, it lacks the adaptive capability to adjust the memory span for different tasks. To address these limitations, we propose FracEncoder, a context encoder based on fractional-order neural differential equations. First, FracEncoder leverages the nonlocal property of the fractional-order derivative and uses a power-law kernel to directly incorporate the trajectory of the thought process into the evolution of the current state, effectively overcoming the temporal locality limitations of traditional models. Second, the fractional order $\alpha$ is set as an end-to-end learnable parameter. It explicitly characterizes how strongly the system anchors to its history, so the model can discover a suitable memory span for each task. We evaluate FracEncoder on more than ten benchmarks across three settings, namely partially observable tasks, meta reinforcement learning, and delayed-observation control. FracEncoder consistently matches or outperforms representative baselines, including GPIDE, GRU-ODE, ReSeL, and LRU. On the challenging 8-step delayed-observation task, it reaches average returns of $-511.5 \pm 7.9$ on Pendulum and $732.1 \pm 152.7$ on Hopper. As a plug-in module, FracEncoder also yields stable gains across different reinforcement learning algorithms. Ablation studies further show that the learned $\alpha$ aligns with the intrinsic memory demand of each task, providing an interpretable physical measure of the cognitive complexity of non-Markovian tasks. The code is available at https://anonymous.4open.science/r/FracEncoder-60BA.

The rapid deployment of generative AI has amplified the critical need for Training Data Attribution to ensure transparency and accountability. However, current parametric approaches require computationally prohibitive access to model weights, while similarity-based methods ignore deep structural context. We propose a novel probabilistic framework that operates entirely in a black-box setting. Our method fuses continuous feature similarities with discrete, domain-specific Knowledge Graphs (KGs). This approach ensures the attribution is grounded in structural reality, explicitly rewarding highly specific historical samples while preventing generic background data from dominating the results. We evaluate our framework across two distinct domains where linking outputs to data and domain context is inherently complex: abstract artistic image synthesis and high-dimensional physical weather forecasting. Extensive benchmarking demonstrates the robust efficacy of our approach. In the artistic domain, it achieves a strong Linear Datamodeling Score that exceeds standard black-box similarity baselines, while closing much of the gap to gradient-based estimators. We additionally present a cross domain feasibility case study in environmental forecasting, where we use domain KGs to retrieve physically consistent historical analogs for regional flood forecasts, improving geographic localisation over a latent-only baseline. Operating entirely without internal model access, our approach provides an efficient, interpretable mechanism for post-hoc influence analysis and domain-grounded retrieval.

Visual state space models (SSMs) have emerged as efficient alternatives to attention-based backbones, yet their performance remains sensitive to how visual evidence is sampled and propagated. Deformable visual Mamba methods address fixed scanning by predicting adaptive sampling locations, but offset prediction is still driven primarily by local responses, producing locally plausible samples that are weakly coupled to the SSM's recurrent state evolution, particularly in off-center or multi-object scenes. We present **Foveal-Mamba**, a scan-path-aware deformable visual Mamba framework that reformulates offset prediction as recurrent scan-path prediction. Two components drive this design. First, an **Inside-Out Ring Scan** organizes visual tokens along a center-to-periphery path, providing a stable propagation prior that does not assume object centering. Second, a lightweight Mamba module embedded within the offset prediction network forms the **Recurrent Scan-Path Offset Prediction Network (RS-OPN)**, which predicts offsets from hidden states accumulated along the ring path. RS-OPN tightly couples deformable sampling with recurrent state evolution and produces coherent, object-aware sampling trajectories. Foveal-Mamba consistently outperforms strong baselines across multiple benchmarks. On ImageNet-1K, Foveal-Mamba-Tiny achieves 84.3\% Top-1 accuracy, surpassing DAMamba-Tiny by 0.5\% with fewer parameters and FLOPs. On ADE20K semantic segmentation, Tiny/Small variants reach 50.8/51.8 mIoU. On COCO, it achieves 48.9/50.2 box AP and 43.7/44.9 mask AP for object detection and instance segmentation, respectively. Qualitative results further demonstrate earlier object focus and more stable activations in multi-object scenes.

Automated cardiac MRI quantification is commonly framed either as dense segmentation followed by voxel counting or as direct regression of global measurements. The two paradigms are difficult to unify: segmentation is visually interpretable but label-intensive and output-heavy, while regression is compact but less verifiable. We propose Fourier Contour Learning, which represents cardiac boundaries with compact anatomical Fourier contours. The predicted coefficients define smooth, interpretable contours and enable differentiable volume computation, connecting mask supervision, measurement supervision, and unlabeled-image regularization within one framework. We instantiate this representation with an anatomy-query decoder and cross-slice attention which creates a traceable path from image to contour to clinical measurement. Across three public datasets and an in-house all-phase cohort, our method achieves segmentation accuracy comparable to strong dense-prediction baselines, improves boundary agreement, and reduces clinically relevant volume error while using only a small number of output parameters per structure. We further show that the learned model provides an efficient interface for vision-language question answering and surface reconstruction. These results demonstrate the potential of Fourier contours as a unified intermediate representation for scalable, traceable, and clinically grounded cardiac analysis. Code will be publicly available upon acceptance.

Symmetry-aware learning is typically framed as equivariance to a single group action, but many real-world distribution shifts are typed, partial/non-invertible, and compositional (e.g., modality changes, occlusion, subsampling, intervention chains). These shifts are better modeled by a category of transformations whose objects represent data contexts and whose morphisms represent admissible transformations between contexts. We thus extend symmetry-aware machine learning from groups to such transformation categories; enforcing categorical equivariance on neural architectures gives stronger robustness than group equivariance. We ground this in both theory and experiments. We formulate a universal approximation theorem for category-equivariant architectures and show density in the space of equivariant continuous transformations. We present experiments on compositional OOD shifts, demonstrating that enforcing categorical equivariance yields measurable robustness gains over group-equivariant and non-equivariant baselines.

Accurate 3D surface reconstruction from unposed images remains a fundamental challenge in computer vision. Recent feed-forward pointmap methods eliminate the need for camera poses but inherently produce discrete, sparse representations. In this paper, we present a generalizable pipeline that directly recovers continuous, high-fidelity 3D surfaces from unposed images by seamlessly integrating pointmap- and ray-based representations. Our approach first extracts explicit geometric priors using a pre-trained pointmap model. A query-view-centric selection module then identifies geometrically relevant reference views via a robust surfel voting mechanism. Next, a cross-attention regressor bridges target query rays with reference features to estimate a continuous coarse surface. Finally, a raylet-based module aggregates local 3D features to carve out high-frequency details and analytical normals. Trained as a single foundation model on 9 diverse datasets, our method demonstrates exceptional zero-shot generalization on 6 unseen datasets, clearly surpassing state-of-the-art baselines in geometric accuracy and detail preservation.