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cs.AIcs.LGeess.SY Emile Anand, Mohammed Rehan Parwani, Xinyuan Cao · Oct 20, 2026

Multi-token prediction (MTP) accelerates language model decoding by drafting several future tokens in one forward pass, but the speculation horizon must be fixed before drafting and the best length varies with context. This paper frames horizon selection as an online survival problem: it predicts per-position rejection hazards to forecast how long a draft prefix will survive exact verification, then adaptively picks the horizon maximizing expected tokens per second. The resulting controller, AMTP, requires no retraining, leaves the target verifier unchanged, and comes with a sublinear throughput-regret bound against the best horizon at each visited context.

Multi-token prediction (MTP) can accelerate language-model decoding by drafting several tokens and verifying them in a single target-model pass. However, the best speculation horizon changes with context: longer drafts offer greater amortization when reliable, but can waste compute on suffixes discarded after a rejection. Unlike autoregressive drafting, where a stopping rule can decide token by token, MTP must fix the horizon before drafting, as all heads fire in the same forward pass. We therefore formulate horizon selection as an online control problem, using verification feedback to learn how far the draft can be trusted in each context, and introduce Adaptive Multi-Token Prediction (AMTP): a lightweight controller that requires no retraining and leaves the exact verifier unchanged. To guide horizon selection, we characterize the expected number of tokens committed at each horizon via acceptance survival, the probability that a draft prefix is fully accepted. Before each round, AMTP predicts how far the draft is likely to survive and picks the horizon with the highest expected tokens per second, learning freely from every verification pass. Theoretically, we show that any online learner's prediction error translates into throughput regret against the best horizon for each context, and in turn into a bound on wall-clock completion time. With online gradient descent, this regret is sublinear. Across five draft-target pairings built on Llama-3.1-8B-Instruct with Medusa heads, Meta's MTP models, and Qwen3-4B-Inst-2507-MTP, evaluated on AIME 2025 and GSM8K, AMTP decodes up to 4.1x faster than standard decoding and matches or outperforms the fixed window in 8 of 10 settings, with throughput gains of up to 10%.
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cs.IRcs.CL Aaditya Chauhan, Arun Agarwal · Oct 22, 2026

Hybrid retrieval—fusing lexical BM25 with dense neural retrievers—is the default recommendation in modern search stacks, usually justified by aggregate benchmark gains. This paper challenges that consensus by diagnosing what it calls the "fusion tax": the frequency and severity with which fusion hurts individual queries relative to the better of its two components or to a deployable dense-only baseline. Through exhaustive experiments across seven BEIR corpora, five encoders spanning 22M–596M parameters, and multiple fusion functions, the authors show the tax is material, pervasive, and undiminished by encoder scale, and they derive practical guidance for when to fuse and which method to choose.

Hybrid retrieval, which fuses a sparse lexical retriever with a dense neural one, is widely recommended in the software documentation surveyed in September 2026, usually with reciprocal rank fusion (RRF), on the strength of aggregate gains. We ask what fusion costs on individual queries, treating "do not fuse" as a first-class outcome, in the setting in which hybrid retrieval is deployed: a standard Anserini BM25, five dense encoders spanning 22M-596M parameters and three model generations, a learned-sparse (SPLADE) alternative, and a cross-encoder second stage, on seven BEIR datasets and three fusion functions. Even the best method, dense-weighted score interpolation, ranks relevant documents below the better of its two components on 13-48% of queries and below the deployable dense-only retriever on 8-21% (14-48% and 11-25% at a weight selected under leave-one-corpus-out validation), while beating dense-only in aggregate on every corpus with the primary encoder; the downside is significant under loss-averse risk-sensitive evaluation on six of the seven corpora. We call this loss the fusion tax. It is mostly a ranking effect that preserves recall in aggregate, it is most likely on the queries that only one retriever covers, and it persists across the encoder ladder and the SPLADE substitution. RRF carries the higher tax wherever the dense retriever is clearly stronger and only beats dense-only where the two components are balanced. Fusion failure is weakly predictable within a corpus but transfers unreliably across corpora, because the features that predict it change sign with the sparse-dense balance. A cross-encoder recovers part of the tax only where it is itself reliable. We distill these findings into guidance that keys the fusion decision to the measured sparse-dense balance of the target corpus.
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cs.DBcs.CL Zhao Tan, Xianglong Bao, Zhipeng Xi et al. · Oct 22, 2026

Time series databases store billions of points, yet answering natural-language shape queries like "plunge and then recover quickly" remains hard because large language models must bridge free-form language to raw numeric windows. TT-SAX proposes a minimal redesign of SAX that adds a second track of trend letters measured across neighboring segments, letting an LLM compile shape queries into regular expressions that can be matched efficiently at database scale. The paper is significant because it reframes symbolization design around LLM usability rather than classical distance or compression metrics.

Natural language querying for time series databases aims to let users find what they need in long histories of data by asking in plain language. Shape queries ask how a series moves. They are the main challenge of this task. Recent work makes them feasible by using symbolization as a bridge between the query and the long history. However, existing symbolizations were designed for compression, similarity indexing, or classification. What a symbolization should provide for natural language querying has not been systematically studied. We therefore examine the definitions of six classical symbolizations against this task and identify three limitations. (1) Direction is missing from the string, (2) direction is measured at too small a scale, and (3) the letters are arbitrary. Three design principles follow. We follow these principles and make a minimal redesign of SAX called TT-SAX (two-track SAX). The level letters stay. Each segment gains a trend letter. It is measured across neighboring segments rather than inside one, and graded to match the adjectives that queries use. We conduct extensive experiments on the public NLQTSBench benchmark, comparing TT-SAX with the six classical symbolizations across six LLMs. TT-SAX outperforms all six on shape queries, and ablations trace its gains back to the three limitations one by one. This paper is the first systematic study of time series symbolization with natural language querying as the design goal. It provides a foundation for future research on this task. Our code is available at https://github.com/Atlamtiz/tt-sax.
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cs.CVcs.LGcs.RO Yunfei Xie, Howard H. Qian, Shiyi Lan et al. · Oct 22, 2026

Evaluating robotic foundation models still relies on expensive closed-loop rollouts in simulation or reality. This paper proposes Sensorimotor Alignment ($S^2$), a training-free offline metric inspired by the Platonic Representation Hypothesis, which scores how well a model's sensory embeddings align with the geometry of recorded end-effector trajectories. The authors find positive correlations between $S^2$ and task success across vision-language-action models, raw vision-language models, world action models, and real-robot policies, and argue the metric can cheaply rank models and diagnose representation-level behavior.

Robotic foundation models are typically evaluated through costly closed-loop rollouts, which motivates cheap offline proxies for model capability. The Platonic Representation Hypothesis (PRH) suggests that as representations improve, different modalities such as vision and language converge toward a shared statistical model of reality. We ask whether motion trajectories form another such modality: as embodied models become more capable, should their sensory representations converge toward the structure of physical motion? To examine this, we propose Sensorimotor Alignment ($S^2$), a training-free offline metric that measures how well a model's sensory representation aligns with the geometry of physical motion. We find that $S^2$ correlates positively with downstream robot task success across embodied model families, making it a low-cost offline proxy for prioritizing models before closed-loop evaluation. $S^2$ can also identify promising vision-language model (VLM) backbones even before costly fine-tuning into vision-language-action models (VLAs). Beyond this correlation, $S^2$ offers representation-level explanations for phenomena observed in VLAs and world action models (WAMs). With $S^2$, we extend PRH to embodied models and make sensorimotor alignment empirically measurable, offering insight into why an embodied model succeeds beyond its closed-loop success rate.
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math.NAcs.LGcs.NA Xin He, Huan Lao, Xiliang Lu et al. · Oct 22, 2026

This paper studies P-trainable neural networks, where a proportion P of hidden neurons are trainable and the rest stay fixed as random features, bridging random feature methods and fully trainable networks. The authors establish two-layer approximation bounds showing that a small trainable fraction can capture most of the gain when initialization mismatch is large, yielding a phase transition in rates of the form $\mathcal{O}(((P/\kappa_1^*+(1-P)/\kappa_0^*)m/\log m)^{-\alpha})$. They verify these assumptions explicitly for spherical biased-ReLU features and present numerical experiments showing analogous phase transitions in training losses across architectures with up to 15 layers.

Constructing accurate and computationally tractable approximation spaces is a fundamental task in scientific computing. Partially trainable neural networks bridge fixed random features and fully adaptive representations. This paper quantifies a phase transition pattern in approximation bounds and observes analogous behavior in training errors: a rapid but smooth initial improvement followed by diminishing returns, with a sharper transition under greater initialization mismatch. Under polynomial spectral decay with exponent $\alpha>1$ and leverage compatibility, we establish a squared $L_2$ approximation rate $\mathcal{O}((\kappa_P\log(m/\delta)/m)^\alpha)$ for two-layer networks of width $m$ and trainable proportion $P$, where $\kappa_P=(P/\kappa_1^*+(1-P)/\kappa_0^*)^{-1}$. The bound holds uniformly over the unit ball of a reproducing kernel Hilbert space (RKHS) with probability at least $1-\delta$. The constants $\kappa_0^*$ and $\kappa_1^*$ quantify the fixed and trainable groups' sampling mismatches relative to the target RKHS. For spherical biased-ReLU features in dimension $d$, we verify these assumptions with $\alpha=(d+2)/(d-1)$ and $\kappa_0^*=4\sqrt{2}\tau(d+1)/d$ for initialization scale $\tau\ge1$, and $\kappa_1^*=1$ under ridge leverage sampling. For $d=5$ and $\tau=10$, a trainable proportion of approximately $4.1\%$ captures $90\%$ of the reduction in the approximation bound from $P=0$ to $P=1$. A structured three-layer example illustrates how a few trainable first-layer neurons exploit fixed downstream blocks through nonlinear composition. Numerical experiments across diverse settings, including networks with up to 15 layers, exhibit similar phase transitions in training errors.
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stat.MLcs.LGstat.ME Isaac Gibbs, Elise L. Han, Ryan J. Tibshirani et al. · Oct 22, 2026

AI systems increasingly make consequential decisions, but fully auditing every output is infeasible at scale. This paper studies selective auditing: sequentially deciding when to trust an AI decision versus escalate it to an expert, using only a scalar confidence score. The authors frame this as an online constrained optimization problem and derive algorithms that guarantee the fraction of unaudited errors stays below a user-specified threshold α without any distributional assumptions. The core contribution is an optimally efficient algorithm that provably minimizes audit effort for both adversarial and i.i.d. data streams.

We consider online monitoring of an AI system that produces a sequence of decisions. At each round, the system outputs a proposed decision together with a confidence score estimating the trustworthiness of the decision. The decision and confidence score need not be produced by the same model: for example, one agent may propose a decision, while a separate verifier agent evaluates it and outputs a correctness or safety score. Based on this information, we must decide whether to accept the AI decision automatically or consult an expert, such as a human auditor, who reviews the proposal and either accepts or corrects it. We formulate this task as an online constrained optimization problem in which the goal is to minimize the frequency of expert auditing while guaranteeing that the fraction of AI errors that go unaudited stays below a user-defined threshold. We derive a family of algorithms with provable error-control guarantees with no assumptions, including a method that is optimally efficient: it asymptotically attains the best achievable auditing rate for both adversarial and i.i.d. data streams. Experiments on screening harmful requests to large language models, qualitative text annotation, and data labeling show that our methods achieve valid error control in practice while substantially reducing the need for human auditing compared to baselines.
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cs.CV Niklas Berndt, Xianghui Xie, Enes Duran et al. · Oct 22, 2026

PiHand tackles the synthesis of physically plausible dexterous hand-object interactions by learning a latent interaction prior from simulated mocap-tracking experts. Its three-stage pipeline—expert RL tracking, VAE distillation, and bounded residual latent exploration—enables zero-shot manipulation of unseen objects and trajectories, and even transfers to tasks like catching and bimanual handover that are rare or absent from the training data. The core thesis is that embedding interaction physics directly into the latent space outperforms both raw action-space RL and hand-only priors in sample efficiency and success rate.

Synthesizing physically grounded dexterous hand-object interactions is important for VR/AR, gaming, and robotics, yet remains challenging because subtle contact dynamics, diverse object geometries, and target trajectories must be jointly respected while maintaining natural grasps. Existing methods either track mocap trajectories with limited transfer to novel objects, or rely on hand-only generative priors that fail to capture coupled hand-object motion, sacrificing contact fidelity and sample efficiency. To tackle these challenges, we introduce PiHand, a Physically grounded Interaction-aware Hand motion synthesis framework. PiHand first trains expert policies that track mocap demonstrations in simulation, distills them into a unified hand-object interaction prior using a goal-conditioned VAE, and finally solve diverse dexterous manipulation tasks through bounded residual exploration in its latent space. With only a single reward and no complex curriculum training, this yields general tabletop manipulation policies that generalize to unseen objects and trajectories on GRAB and DexYCB. The same prior transfers to object catching and bimanual handover, two tasks that are rarely seen in its training data. Across all tasks, PiHand consistently outperforms baselines in all metrics. We will release the processed data and model checkpoints.
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cs.CV Ruicong Liu, Liangyang Ouyang, Fengbo Lan et al. · Oct 22, 2026

AnyGameRenderer tackles the programmer-art problem of agent-built games by converting crude gameplay video into stylized, high-fidelity output via a rank-128 LoRA on the 33B MiniMax-H3 ref2va model. It accepts plain video inputs---gray blockouts, colored primitives, semantic maps, or wireframes---without engine G-buffers or per-object labels, and aims to preserve entity count, timing, and position across genres from tower defense to kart racing. The authors assemble roughly 10k paired clips from three sources and introduce an entity-level benchmark of 753 annotated entities to measure correspondence, improving temporal match over the zero-shot base.

AI coding agents can now build small playable games in minutes, but the results usually look like programmer art: gray blockouts, colored geometric primitives, and flat semantic blobs. We present AnyGameRenderer, a video-to-video generative renderer that turns such footage into high-quality visuals with characters, motion detail, and effects. Throughout, it keeps the layout, camera, and every entity's position and timing intact. Our AnyGameRenderer generalizes across a wide range of genres that agents build, such as tower defense, auto-battlers, top-down survivors, turn-based battles, kart racing, and crowd runners. AnyGameRenderer takes plain video as its game-state input, with no complex representations such as engine G-buffers, per-object class labels, or low-poly proxies. Gray blockouts, colored primitives, semantic maps, and wireframes all work as input. It also preserves entity correspondence: group counts stay correct, and entities appear and disappear on the right frame. We implement AnyGameRenderer by LoRA fine-tuning MiniMax-H3 ref2va, a 33B reference-video-conditioned video generation model. Training uses $\sim$10k paired clips from three sources: (i) multi-stream rendering data from 38 agent-made games exported from GEAR, an AI game-creation tool; (ii) two-stream rendering data from Unreal Engine, with programmatically controlled crowds, count changes, and entity scales; and (iii) real gameplay recordings, with pairs reconstructed via 3D-box detection. To evaluate the entity correspondence, we propose an entity-level benchmark of 59 held-out cases with 753 entities, scored against ground-truth boxes. Compared with the base model, AnyGameRenderer better preserves entity correspondence: temporal match rises from 50.9\% to 62.9\%, missed count changes fall from 34.7\% to 21.3\%, and fewer entities are hallucinated or left unrendered.
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cs.CVcs.LG Sy-Tuyen Ho, Anirudh Satheesh, Soham Chawathe et al. · Oct 22, 2026

Dataset-use auditing for text-to-image models is difficult because fine-tuned models absorb collection-level visual style without reproducing individual training images. SpectralCanary addresses this by blending a fixed canary image into the low-frequency Fourier content of every collection image before release, preserving captions and avoiding auxiliary generation or per-image optimization. A lightweight verifier then detects the transferred spectral signature in a suspect model's black-box outputs. The method achieves strong detection rates across multiple architectures and domains with minimal fidelity loss, establishing low-frequency traces as a practical auditing mechanism.

Auditing whether a text-to-image (T2I) model was fine-tuned on a particular image collection is difficult: a model can absorb collection-level visual characteristics without reproducing training images. Proactive dataset-use auditing plants a shared signal in a dataset before release, then later checks whether that signal appears in a suspect model's generated outputs. Existing approaches often trade off verifiability, fidelity, robustness, and deployability. We introduce $\textbf{SpectralCanary}$, which uses a smooth low-pass mask to blend a fixed canary image into every collection image while leaving captions unchanged and requiring neither auxiliary generation nor per-image optimization. A lightweight verifier detects the transferred signal in suspect-model outputs. Across eight tests on the Pokemon dataset and three realistic data transformations, spanning two architectures families, SpectralCanary achieves the highest average per-generation TPR@$1\%$ FPR ($91.1\%$) and fixed threshold model-level accuracy using 30 generations ($94.8\%$) among the evaluated methods. Across five datasets spanning artistic, medical, satellite, and fashion domains with SD3.5, SpectralCanary averages $92.4\%$ per-generation TPR@$1\%$ FPR while preserving the released images (SSIM $0.989$, LPIPS $0.022$) with a near-zero mean change FID (mean $\Delta$FID $0.05$) across datasets. Matched-energy ablations on Pokemon and ROCOv2 support our design choice, low-frequency placement transfers more reliably compared to mid/high-frequency placement. Under the evaluated adaptive attacks, the most effective removal requires aggressive modification and incurs more than $25$ $\Delta$FID points. These results identify low-frequency visual signals as effective carriers for collection-level T2I audit traces.
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cs.LG Jonathan T. Barron, Dan Gnanapragasam, Michael Tschannen · Oct 22, 2026

Standard softmax and cross-entropy hide two floating-point bugs: Softmax Collapse rounds the target gradient to zero once logit margins cross a precision cliff, while Softmax Cancellation produces phantom gradients when a student network approaches its teacher. Barron et al. rewrite both functions in log-space using softplus, expm1, and log1p to recover accurate, zero-sum gradients across bf16, fp32, and fp64. They tie these numerical issues to the Slingshot phenomenon in grokking and derive a clean equilibrium for logit margins under AdamW with weight decay.

Standard implementations of softmax, log-softmax, and cross-entropy have two numerical bugs. The first bug, Softmax Collapse, rounds the target logit's gradient to zero if that one logit is much larger than the others, resulting in gradients that no longer sum to zero. The second bug, Softmax Cancellation, occurs when student logits are close to teacher logits, and produces non-zero gradients even when the student and teacher logits are equal. We present simple implementations of log-softmax, softmax, and cross-entropy that fix both bugs. Our fix eliminates the previously-observed "Slingshot" phenomenon, speeds up grokking with weight decay, prevents accuracy collapse without weight decay, stops student networks from drifting away from the teacher during distillation, and shows that after memorization, logit growth is bounded by an equilibrium between weight decay and Adam's $\epsilon$ hyperparameter.
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cs.LGstat.ML Yuxuan Cai, Yuan Cao · Oct 22, 2026

This paper asks whether transformers that generate intermediate reasoning steps can discover new algorithms beyond the teacher they are trained to imitate. It designs a two-stage training protocol for in-context linear regression—first supervised by gradient descent, then by ground-truth weights—and proves that a one-layer linear self-attention transformer learns the Heavy-Ball method. The result matters because it gives a rigorous case where chain-of-thought reasoning internalizes acceleration rather than simply memorizing the supervised update.

Modern transformers often solve complex tasks by generating and refining intermediate reasoning steps. To develop a theoretical understanding of chain-of-thought (CoT) reasoning, a notable recent study by Huang et al. (2025) viewed transformers as algorithm executors, and showed that when transformers' CoT steps are supervised by a gradient-descent teacher, they can learn to implement gradient descent for in-context weight prediction in linear regression. In this paper, we study the same in-context weight prediction task but ask whether CoT reasoning can go beyond merely imitating the teacher algorithm. We show that, after initial supervision from a gradient-descent teacher, further trajectory-level supervision using the true regression weights leads the model to implement the Heavy-Ball method, thereby achieving acceleration over the original teacher. Notably, this accelerated algorithm emerges without supervision from any Heavy-Ball teacher. Our results provide a concrete theoretical example in which transformer reasoning can discover new algorithms through training, rather than merely imitate the algorithm used for supervision.
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cs.CV Minkyun Seo, Hyungtae Lim, Jaesik Park · Oct 22, 2026

MixPT tackles the trade-off between computational cost and scene-wide interaction in point cloud transformers. It interleaves fixed-order window attention blocks with periodic global attention blocks, using spatial pooling to keep global attention feasible when the number of tokens is large. The authors show that this hybrid schedule lowers per-forward latency compared to both pure window and pure global baselines while maintaining competitive accuracy on indoor and outdoor 3D segmentation benchmarks.

Point cloud transformers aim to capture detailed local geometry and relationships across a scene at a manageable computational cost. Two common approaches are window attention and global attention. They differ in how they enable scene-wide interaction, which refers to information exchange among tokens across a scene. Window attention reduces computational cost by restricting self-attention to groups of tokens called windows; in serialized designs, each window contains a fixed number of consecutive tokens from a spatially ordered sequence. Because each block only directly connects tokens within the same window, information exchange across windows relies on changes in window membership across blocks and hierarchical pooling. Global attention, in contrast, directly connects all tokens within a scene, but computing attention over all token pairs can be costly when the number of tokens is large. To balance computational cost and scene-wide interaction, we introduce MixPT, a point transformer that uses a mix of window and global attention blocks in an interleaved schedule, while retaining a single fixed serialization pattern for its window blocks. For scenes with a large number of tokens, MixPT applies global attention to spatially pooled tokens and returns residual updates to the original-resolution stream. Across indoor and outdoor benchmarks, MixPT achieves competitive accuracy with lower latency than representative window and global attention baselines. We further demonstrate the feasibility of scaling the attention stage in depth by repeating the interleaved pattern of window and global attention blocks.
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cs.LG Hayden Prairie, Jacob M. Ryan, Taylor Berg-Kirkpatrick et al. · Oct 22, 2026

Looped language models reuse the same parameter block many times to improve quality without inflating weight memory, but each recurrence still stores its own KV-cache, so inference memory grows linearly with depth. This paper studies when and why the final recurrence's KV-cache can be shared across earlier recurrences—a property the authors call KV-shareability—finding that contractive residual dynamics are necessary but not sufficient. They introduce a two-stage recipe (stochastic-depth pretraining plus a lightweight post-training corrector called BeNice!) that reliably enables near-lossless KV-sharing and composes with existing cache-compression techniques.

Looped architectures scale quality while keeping parameter count fixed by repeatedly passing activations through the same block of layers. During inference, each recurrence generates independent KV-caches, causing memory to grow linearly. To address this challenge, prior work has proposed KV-sharing (i.e., sharing KV-caches across depth), finding that, in some cases, the KV-cache of the final recurrence can be shared with the earlier recurrences without quality loss, a property we denote as KV-shareability. However, the mechanisms underlying KV-shareability remain poorly understood, with even identically trained looped architectures not consistently exhibiting it. In this paper, we study how KV-shareability can be enabled in looped models. We propose a two-stage method: in the first stage, we use stochastic depth during pretraining, which induces contractive residual dynamics that drive representations toward a common limit across recurrences. In the second stage, we propose BeNice!, a post-training method that broadcasts the final recurrence's KV-cache into the first recurrence, training it to produce compatible residuals while preserving the original model's quality. As a result, BeNice! enables KV-shareability while matching standard finetuning's unshared validation perplexity. Using BeNice!, we show that KV-sharing is complementary to alternative KV-compression methods, composing with memory-efficient sequence mixers (e.g., multi-latent attention, Kimi delta attention) and low-precision KV-cache quantization (e.g., fp8, mxfp8, nvfp4). Finally, in simulated low-memory, long-context inference, KV-sharing improves cache hit rates by up to 31.4%, increases throughput by up to 23.6%, and reduces p90 time-to-first-token by up to 83.6%.
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cs.ROcs.CV Eun Sun Lee, Minkyun Seo, Gwangtak Bae et al. · Oct 22, 2026

This paper tackles cross-session indoor navigation, where an agent must reach a prior-session goal despite scene changes, sensor differences, and partial overlap. The key idea is a sparse topometric graph whose nodes compress local 3D geometry around traversable anchors and whose edges encode traversable distance, enabling both memory-efficient storage and learned graph matching for alignment. The approach matters because it promises to slash map memory by over two orders of magnitude while outperforming dense grids, appearance maps, and semantic graphs on standard benchmarks.

A conventional embodied agent in an indoor environment builds a map by accumulating noisy real-world measurements and results from heavy inference to guide navigation. While the detailed measurements may differ due to scene changes or sensor settings, the unique topological structure of navigable passages or the connectivity between rooms may provide training-free guidance that complements local observations. We propose a sparse topometric graph as an efficient structural representation for robust indoor navigation, alleviating the need for fine-grained matching, which is computationally expensive, memory-intensive, and prone to real-world variations. The map consists of nodes that encode local 3D geometry and distance-weighted edges that capture traversable connectivity. A learned graph-matching network finds consistent subgraph structures across sessions by considering both node-level geometric descriptors and neighborhood connectivity. The holistic contextual matching is robust to local ambiguities caused by weak distinctiveness or repetitive structure, and establishes stable correspondences despite local scene changes, different sensor modalities, or limited spatial overlap. We analyze the practicality of the graph through cross-session point-goal navigation, where a goal specified in a prior reference map must be reached from an unknown initial pose in a later session. Experiments show that our method achieves the highest success rates (77.1% on Gibson and 40.0% under 3D-FRONT scene changes), while reducing memory by more than two orders of magnitude compared to point-level representations. The proposed approach further supports cross-session alignment and goal-directed navigation with strong scalability and robust real-world transfer.
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cs.CVcs.LG Jihoon Hong, Alireza Kheirandish, Rohan Sanda et al. · Oct 22, 2026

Local anomaly detection in images with multimodal inlier distributions—such as medical scans, faces, and X-ray baggage—remains challenging for industrial-defect methods that rely on heuristic reconstruction errors or feature distances. LACToS introduces a principled alternative by scoring superpixels via statistical typicality under the conditional inpainting posterior of an inlier diffusion model, made tractable by grouping pixels into superpixels and using a single denoising posterior as a cheap proxy. This shift from point estimates to distribution-aware testing matters because it directly addresses the false positives that arise when normal images contain diverse, context-dependent content.

Local anomaly detection is the task of identifying spatially confined anomalous or out-of-distribution (OOD) regions within an otherwise in-distribution (ID) image. Most existing methods are designed for a specific context, with a strong focus on industrial defect detection, where they achieve excellent performance on well-established benchmarks. However, we observe that these methods can exhibit significant performance drops in other contexts, especially when the inlier distribution is multimodal. To account for this inlier complexity, we propose LACToS, a principled local OOD detection method based on statistical typicality and made tractable through two innovations: (i) grouping pixels into superpixels and (ii) using a computationally efficient proxy to estimate typicality. We evaluate LACToS across three diverse applications spanning medical imaging, human faces, and X-ray security screening. LACToS performs more robustly than prior methods across these benchmarks. The code is released here: https://github.com/voilalab/LACToS.
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cs.LG Franco Rugolon, Ioanna Miliou, Panagiotis Papapetrou · Oct 22, 2026

CRANE addresses the lack of post-hoc counterfactual explanation methods for multimodal classifiers, where applying unimodal techniques independently produces incoherent, chimeric explanations that violate cross-modal constraints. The framework retrieves real training instances from the target class via several nearest-neighbour strategies, most notably Multimodal Consensus Retrieval (MC-R), which intersects per-modality neighbour sets to preserve joint distributional coherence. By operating without model internals for most strategies and grounding explanations in observed data, CRANE aims to deliver plausible, actionable counterfactuals across heterogeneous inputs including text, images, tables, and time series.

Counterfactual explanation methods have been introduced for unimodal settings, with dedicated frameworks for tabular, timeseries, text, and image data, yet no post-hoc method has been designed for classifiers that learn from multimodal inputs. Existing explainability methods for multimodal classifiers apply modality-specific attribution independently to each input, which fails to yield coherent explanations and does not transfer to arbitrary pre-trained multimodal architectures. To address these shortcomings, we present CRANE (Counterfactual Retrieval via Agnostic Nearest-neighbour Explanations), the first post-hoc, model-agnostic framework for nearest-neighbour multimodal counterfactual generation that retrieves real training examples from the target class as candidate explanations, ensuring plausibility by construction. Across four heterogeneous datasets and three fusion strategies, we show that Multimodal Consensus Retrieval (MC-R), which intersects per-modality neighbour sets to identify instances jointly close to the query in every modality, emerges as the strongest multimodal strategy, achieving the best or joint-best outcome on three of four datasets while grounding every explanation in the joint training distribution. Unimodal strategies remain competitive when a single modality dominates the decision boundary.
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cs.LGcs.CR Qi Li, Xinchao Wang · Oct 22, 2026

On-policy self-distillation trains language models by distilling privileged self-supervision over the model's own rollouts, yet its privacy risks have remained almost entirely unexplored. This paper presents the first study of membership inference attacks against such systems, showing that the training imprint is sparse and concentrates on uncertainty-sensitive reasoning tokens rather than spreading uniformly across outputs. The authors propose OP-Print, a unified gray-box and black-box attack framework that either aggregates privileged teacher-student residuals directly or infers them from restart-based output-basin stability. Their empirical results suggest that on-policy self-distillation introduces a distinct, previously overlooked privacy leakage surface that conventional MIA heuristics fail to capture, raising important concerns for privacy auditing of modern post-training pipelines.

On-policy distillation has been widely adopted for alleviating the distribution mismatch of off-policy distillation. Self-distillation further removes the need for an external teacher by using the student's own outputs, enhanced with extra context or demonstrations, as supervision. This teacher-free design makes on-policy self-distillation practical, yet its privacy risks remain largely unexplored. In particular, using two coupled views of the same training example may strengthen its memorization. Motivated by this, we present the first study of membership inference attacks against on-policy self-distillation. We investigate both gray-box and black-box threat models and propose a unified attack framework, named OP-Print. OP-Print builds on our finding that the supervision imprint in on-policy self-distillation is sparse and structured, concentrating on uncertainty-sensitive correction sites rather than across the entire rollout. Exploiting this property, we construct attack signals tailored to the two access levels: in the gray-box setting, OP-Print directly aggregates the privileged teacher-student residual correction along the same rollout; in the black-box setting, it measures restart-based output-basin stability as an observable surrogate for the hidden correction process. Across diverse models and distillation schemes, all baseline attacks remain essentially at random guessing even under gray-box access, whereas OP-Print is broadly validated to be effective in both gray-box and black-box settings.
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cs.CV Weihao Gao · Oct 22, 2026

This paper attacks the real-time deployment bottleneck for polyp segmentation by proposing a \sim77K-parameter Lightweight Frame Compensator (LFC) inserted before a frozen backbone. Under $K=3$ frame skipping, LFC fuses three consecutive frames via spatio-temporal attention into a single compensated image, claiming a $2.05\times$--$2.55\times$ throughput gain while recovering most accuracy loss. The core insight is that global-attention Transformers suffer the most from skip-frame jitter, making them the prime beneficiaries of lightweight temporal fusion. Unfortunately, the bulk of the evidence rests on pseudo-labels rather than expert-annotated video ground truth, which undermines the clinical certainty of the reported gains.

Real-time polyp segmentation in computer-assisted colonoscopy is hampered by the difficulty of deploying high-accuracy models under strict latency budgets. Frame skipping, which performs inference every K frames and reuses or interpolates the rest, improves throughput but introduces motion blur and lesion misalignment that degrade temporal consistency. To close this gap, we propose the Lightweight Frame Compensator (LFC), a 77K-parameter plug-and-play module inserted before a frozen segmentation backbone. Operating on a three-frame window, LFC fuses consecutive frames via spatio-temporal attention into a single compensated frame, and is trained only on pseudo-labels generated by a differently seeded model, without any expert annotation. Experiments on three polyp video benchmarks show that LFC recovers most of the accuracy degraded by direct frame skipping and, in several settings, reaches the accuracy of frame-by-frame inference, while retaining a 2.05X--2.55X throughput gain. We further evaluate the temporal stability of three backbones spanning CNN, pyramid Transformer, and global-attention Transformer architectures, revealing a spectrum of sensitivity to frame skipping that arises from how locally or globally each architecture aggregates misaligned input. The compensation gain of LFC follows this spectrum: it is largest for high-capacity Transformer backbones, which achieve the best static accuracy but suffer the most under skip-frame inference. LFC thus offers a lightweight, pluggable, and deployment-friendly route to real-time polyp segmentation.
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cs.CV Tianming Liang, Junyi Pan, Yuxi Li et al. · Oct 22, 2026

Existing vision-language models struggle with fine-grained visual perception, often hallucinating objects or missing fine details. WeVisOne-VL tackles this by unifying object-level and pixel-level tasks—detection, segmentation, matting, OCR, and more—inside a single autoregressive VLM built on Qwen3-VL. It introduces dedicated coordinate tokens and a lightweight 9.6M-parameter pixel decoder triggered by an <OBJ> token, enabling dense outputs without a separate segmentation backbone. Trained on roughly 100M curated images via a three-stage curriculum and mixed-task RL, it aims to move VLMs from broad understanding toward reliable, deployable perception.

Existing vision-language models (VLMs) remain unreliable for fine-grained visual perception. In this report, we present WeVisOne-VL (WeChat Vision All-in-One), a powerful VLM that unifies object-level and pixel-level perception through structured next-token prediction. It supports multiple visual tasks including object detection, referring localization, counting, OCR, segmentation, and matting, enabling localization at any user-specific granularity, from points and boxes to masks and alpha mattes. Architecturally, we integrate a lightweight pixel decoder into the VLM via a special <OBJ> token to generate instance-level pixel outputs. We train the model with a three-stage curriculum SFT followed by mixed-task RL. Across over 30 benchmarks, WeVisOne-VL demonstrates leading performance on both object-level and pixel-level tasks, while maintaining robust rejection for object-absent queries. By releasing WeVisOne-VL to the open-source community, we hope to advance VLMs from broad visual understanding toward truly reliable perception systems for real-world deployment.
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cs.CV Xinyang Lu, Shengzhe Wei, Sheng Tang et al. · Oct 22, 2026

Local feature matching underpins SfM and visual localization, but standard matchers process every image pair independently, which is inefficient and ignores multi-view cues available in star-graph neighbourhoods. MVLoMa addresses this by jointly matching a centre image against all neighbours in a single forward pass, reusing frozen geometry-aware tokens from a multi-view foundation model such as DA3-Giant and adding star-structured cross-attention so the centre aggregates evidence from all neighbours. It preserves the conventional sparse pairwise outputs required by RANSAC while improving strict-threshold pose AUC and cutting matcher compute by roughly $2.2\times$ at $25$ views.

Local feature matching is typically formulated for image pairs, although structure-from-motion and visual localization commonly match one reference image against many retrieved or covisible neighbours. Applying a pairwise matcher independently to these centre-neighbour edges duplicates reference-side computation and prevents the matcher from exploiting complementary multi-view geometric evidence from the remaining observations. To address these limitations, we introduce MVLoMa, a sparse star-graph matcher that extends LoMa from image pairs to multiple views. MVLoMa first uses a frozen multi-view geometry model to jointly describe all images in a star, then injects the resulting cross-view geometric context into local descriptors. It then matches the centre image to all neighbours in a single forward pass through per-view self-attention and bidirectional centre-neighbour cross-attention. For supervision, we derive positive correspondences only from depth-valid, mutually visible dense warps and explicitly penalize high-confidence matches that violate epipolar geometry. On 25-view star graphs from HyperSim, ScanNet++, Mip-NeRF 360, and Tanks and Temples, MVLoMa obtains the best macro-average relative-pose AUC among the compared methods at all three thresholds (58.65/85.41/90.99). Its matcher is 2.20 times faster than sequential evaluation of the 24 centre-neighbour edges. The same design supports four tested frozen geometry encoders -- DA3, $\pi^3$, VGGT, and VGGT-$\Omega$ -- with DA3-Giant performing best on all reported encoder-ablation metrics. Controlled ablations further isolate the effects of geometry-aware descriptors, visibility filtering, geometric negative supervision, and joint multi-view inference.