Computation and Language
Detecting LLM Hallucinations via Embedding Cluster Geometry: A Three-Type Taxonomy with Measurable Signatures
Matic Korun
We propose a
geometric taxonomy of large
language model
hallucinations based on observable signatures in
token embedding cluster structure. By analyzing the static
embedding spaces of 11
transformer models spanning encoder (BERT, RoBERTa, ELECTRA, DeBERTa, ALBERT, MiniLM, DistilBERT) and decoder (GPT-2) architectures, we identify three operationally distinct
hallucination types: Type 1 (center-drift) under weak context, Type 2 (wrong-well convergence) to locally coherent but contextually incorrect cluster regions, and Type 3 (coverage gaps) where no cluster structure exists. We introduce three measurable
geometric statistics: {\alpha} (polarity coupling), e̱ta} (cluster cohesion), and {\lambda}_s (radial information gradient). Across all 11 models, polarity structure ({\alpha} > 0.5) is universal (11/11), cluster cohesion (e̱ta} > 0) is universal (11/11), and the radial information gradient is significant (9/11, p < 0.05). We demonstrate that the two models failing {\lambda}_s significance – ALBERT and MiniLM – do so for architecturally explicable reasons: factorized
embedding compression and
distillation-induced isotropy, respectively. These findings establish the
geometric prerequisites for type-specific
hallucination detection and yield testable predictions about architecture-dependent vulnerability profiles.
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Computation and Language
AD-Bench: A Real-World, Trajectory-Aware Advertising Analytics Benchmark for LLM Agents
Lingxiang Hu, Yiding Sun, Tianle Xia et al. (+6 more)
While Large
Language Model (LLM)
agents have made remarkable progress on complex
reasoning, evaluating them in real-world environments remains an open problem. Existing
benchmarks are largely confined to idealized simulations and fail to capture specialized domains such as advertising and marketing analytics, where tasks require multi-round interaction with professional tools and where ground-truth answers quickly become obsolete as data and platform rules evolve. To address this, we propose AD-Bench, a
benchmark built from real user marketing-analysis requests on a production advertising platform. AD-Bench introduces two key designs: (i) a dynamic ground-truth pipeline that replays expert tool-call trajectories to regenerate answers consistent with the current environment, mitigating answer obsolescence; and (ii) a trajectory-aware evaluation that jointly measures end-to-end answer correctness (Pass@k) and trajectory coverage. Requests are stratified into three difficulty levels (L1-L3) to probe multi-round, multi-tool collaboration. Experiments show that the best model, Claude-Opus-4.7, attains Pass@1 = 76.9% and Pass@3 = 80.4% with 82.7% trajectory coverage overall, yet drops sharply on L3 to Pass@1 = 61.4% and Pass@3 = 65.1%, revealing that even state-of-the-art
agents have substantial gaps in complex advertising analytics.
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All authors Lingxiang Hu, Yiding Sun, Tianle Xia, Wenwei Li, Ming Xu, Lan Xu, Siying Wang, Wei Xu, Jie Jiang
Computation and Language
We can still parse using syntactic rules
Ghaly Hussein
This research introduces a new parsing approach, based on earlier syntactic work on context free grammar (CFG) and generalized phrase structure grammar (GPSG). The approach comprises both a new parsing
algorithm and a set of syntactic rules and features that overcome the limitations of CFG. It also generates both dependency and constituency parse trees, while accommodating noise and incomplete parses. The system was tested on data from Universal Dependencies, showing a promising average Unlabeled Attachment Score (UAS) of 54.5% in the development
dataset (7 corpora) and 53.8% in the test set (12 corpora). The system also provides multiple parse hypotheses, allowing further reranking to improve parsing accuracy. This approach also leverages much of the theoretical syntactic work since the 1950s to be used within a computational context. The application of this approach provides a transparent and interpretable NLP model to process
language input.
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Computation and Language · Cross-listed from cs.AI
REDSearcher: A Scalable and Cost-Efficient Framework for Long-Horizon Search Agents
Zheng Chu, Xiao Wang, Jack Hong et al. (+11 more)
Large
language models are transitioning from generalpurpose knowledge engines to realworld problem solvers, yet optimizing them for deep search tasks remains challenging. The central bottleneck lies in the extreme sparsity of highquality search trajectories and reward signals, arising from the difficulty of scalable longhorizon task construction and the high cost of interactionheavy rollouts involving external tool calls. To address these challenges, we propose REDSearcher, a unified framework that codesigns complex task synthesis, midtraining, and posttraining for scalable searchagent optimization. Specifically, REDSearcher introduces the following improvements: (1) We frame task synthesis as a dualconstrained optimization, where task difficulty is precisely governed by graph
topology and evidence dispersion, allowing scalable generation of complex, highquality tasks. (2) We introduce toolaugmented queries to encourage proactive tool use rather than passive recall.(3) During midtraining, we strengthen core atomic capabilities knowledge, planning, and function calling substantially reducing the cost of collecting highquality trajectories for downstream training. (4) We build a local simulated environment that enables rapid, lowcost algorithmic iteration for reinforcement learning experiments. Across both textonly and
multimodal searchagent
benchmarks, our approach achieves stateoftheart performance. To facilitate future research on longhorizon search
agents, we will release 10K highquality complex text search trajectories, 5K
multimodal trajectories and 1K text RL query set, and together with code and model checkpoints.
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All authors Zheng Chu, Xiao Wang, Jack Hong, Huiming Fan, Yuqi Huang, Yue Yang, Guohai Xu, Chenxiao Zhao, Cheng Xiang, Shengchao Hu, Dongdong Kuang, Ming Liu, Bing Qin, Xing Yu
Computation and Language · Cross-listed from cs.SD
The Interspeech 2026 Audio Reasoning Challenge: Evaluating Reasoning Process Quality for Audio Reasoning Models and Agents
Ziyang Ma, Ruiyang Xu, Yinghao Ma et al. (+9 more)
Recent Large Audio
Language Models (LALMs) excel in understanding but often lack transparent
reasoning. To address this "black-box" limitation, we organized the Audio
Reasoning Challenge at Interspeech 2026, the first shared task dedicated to evaluating Chain-of-Thought (CoT) quality in the audio domain. The challenge introduced MMAR-Rubrics, a novel instance-level protocol assessing the factuality and logic of
reasoning chains. Featured Single Model and
Agent tracks, the competition attracting 156 teams from 18 countries and regions. Results show
agent systems currently lead in
reasoning quality, utilizing iterative tool orchestration and cross-modal analysis. Besides, single models are rapidly advancing via reinforcement learning and sophisticated data pipeline. We details the challenge design, methodology, and a comprehensive analysis of state-of-the-art systems, providing new insights for explainable audio intelligence.
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All authors Ziyang Ma, Ruiyang Xu, Yinghao Ma, Chao-Han Huck Yang, Bohan Li, Jaeyeon Kim, Jin Xu, Jinyu Li, Carlos Busso, Kai Yu, Eng Siong Chng, Xie Chen
Computation and Language · Cross-listed from cs.CY
Reasoning Language Models for complex assessments tasks: Evaluating parental cooperation from child protection case reports
Dragan Stoll, Brian E. Perron, Zia Qi et al. (+3 more)
Purpose:
Reasoning language models (RLMs) have demonstrated significant advances in solving complex
reasoning tasks. We examined their potential to assess parental cooperation during CPS interventions using case reports, a case factor characterized by ambiguous and conflicting information. Methods: A four stage workflow comprising (1) case reports collection, (2)
reasoning-based assessment of parental cooperation, (3) automated category extraction, and (4) case labeling was developed. The performance of RLMs with different parameter sizes (255B, 32B, 4B) was compared against human validated data. Two expert human reviewers (EHRs) independently classified a weighted random sample of reports. Results: The largest RLM achieved the highest accuracy (89%), outperforming the initial approach (80%). Classification accuracy was higher for mothers (93%) than for fathers (85%), and EHRs exhibited similar differences. Conclusions: RLMs'
reasoning can effectively assess complex case factors such as parental cooperation. Lower accuracy in assessing fathers' cooperation supports the argument of a stronger professional focus on mothers in CPS interventions.
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All authors Dragan Stoll, Brian E. Perron, Zia Qi, Selina Steinmann, Nicole F. Eicher, Andreas Jud
Computation and Language · Cross-listed from cs.LG
MAGE: All-[MASK] Block Already Knows Where to Look in Block Diffusion LLM
Omin Kwon, Yeonjae Kim, Doyeon Kim et al. (+3 more)
Block
diffusion LLMs are an emerging paradigm for parallel
language generation, but their KV caching makes
memory access the dominant bottleneck in long-context inference. Sparse
attention, which attends only to a small KV subset per query, can reduce this latency with minimal accuracy loss. In block
diffusion, however, the B
tokens of each block must share a single KV subset, and we show this per-block constraint degrades existing sparse KV
estimators by up to 25% in recall. We address this challenge by exploiting a property that emerges from the block-
diffusion training objective: it aligns the block-average query across denoising steps, so the All-[MASK] block at the first step already reveals the per-block KV subset for the entire trajectory. We exploit this in MAGE ([MASK]-Guided Sparse
Attention), a training-free method that runs one exact
attention pass at the first step and reuses its top-k index sets for all remaining steps within the block. Across three block-
diffusion families on LongBench, MAGE matches Exact
Attention at k=512 with near-lossless accuracy, achieves up to 6.82x end-to-end speedup at 128K context, and runs up to 3.35x and 2.28x faster than Quest and SparseD, designed for AR LLMs and fully bidirectional
diffusion LLMs, respectively.
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All authors Omin Kwon, Yeonjae Kim, Doyeon Kim, Minseo Kim, Yeonhong Park, Jae W. Lee
Computation and Language
Knowing When Not to Answer: Abstention-Aware Scientific Reasoning
Samir Abdaljalil, Erchin Serpedin and Hasan Kurban
Large
language models are increasingly used to answer and verify scientific claims, yet existing evaluations typically assume that a model must always produce a definitive answer. In scientific settings, however, unsupported or uncertain conclusions can be more harmful than abstaining. We study this problem through an abstention-aware verification framework that decomposes scientific claims into minimal conditions, audits each condition against available evidence using natural
language inference (NLI), and selectively decides whether to support, refute, or abstain. We evaluate this framework across two complementary scientific
benchmarks: SciFact and PubMedQA, covering both closed-book and open-domain evidence settings. Experiments are conducted with six diverse
language models, including encoder-decoder, open-weight chat models, and proprietary APIs. Across all
benchmarks and models, we observe that raw accuracy varies only modestly across architectures, while abstention plays a critical role in controlling error. In particular, confidence-based abstention substantially reduces risk at moderate coverage levels, even when absolute accuracy improvements are limited. Our results suggest that in scientific
reasoning tasks, the primary challenge is not selecting a single best model, but rather determining when available evidence is sufficient to justify an answer. This work highlights abstention-aware evaluation as a practical and model-agnostic lens for assessing scientific reliability, and provides a unified experimental basis for future work on selective
reasoning in scientific domains. Code is available at https://github.com/sabdaljalil2000/ai4science .
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Computation and Language
GPT-5 vs Other LLMs in Long Short-Context Performance
Nima Esmi, Maryam Nezhad-Moghaddam, Fatemeh Borhani et al. (+3 more)
With the significant expansion of the context window in Large
Language Models (LLMs), these models are theoretically capable of processing millions of
tokens in a single pass. However, research indicates a significant gap between this theoretical capacity and the practical ability of models to robustly utilize information within long contexts, especially in tasks that require a comprehensive understanding of numerous details. This paper evaluates the performance of four state-of-the-art models (Grok-4, GPT-4, Gemini 2.5, and GPT-5) on long short-context tasks. For this purpose, three
datasets were used: two supplementary
datasets for retrieving culinary recipes and math problems, and a primary
dataset of 20K social media posts for depression detection. The results show that as the input volume on the social media
dataset exceeds 5K posts (70K
tokens), the performance of all models degrades significantly, with accuracy dropping to around 50-53% for 20K posts. Notably, in the GPT-5 model, despite the sharp decline in accuracy, its precision remained high at approximately 95%, a feature that could be highly effective for sensitive applications like depression detection. This research also indicates that the "lost in the middle" problem has been largely resolved in newer models. This study emphasizes the gap between the theoretical capacity and the actual performance of models on complex, high-volume data tasks and highlights the importance of metrics beyond simple accuracy for practical applications.
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All authors Nima Esmi, Maryam Nezhad-Moghaddam, Fatemeh Borhani, Asadollah Shahbahrami, Amin Daemdoost, Georgi Gaydadjiev
Computation and Language · Cross-listed from cs.SD
Investigation for Relative Voice Impression Estimation
Kenichi Fujita and Yusuke Ijima
Paralinguistic and non-linguistic aspects of
speech strongly influence listener impressions. While most research focuses on absolute impression scoring, this study investigates relative voice impression estimation (RIE), a framework for predicting the perceptual difference between two utterances from the same speaker. The estimation target is a low-dimensional vector derived from subjective evaluations, quantifying the perceptual shift of the second utterance relative to the first along an antonymic axis (e.g., “Dark–Bright”). To isolate expressive and prosodic variation, we used recordings of a professional speaker reading a text in various styles. We compare three modeling approaches: classical acoustic features commonly used for
speech emotion recognition, self-supervised
speech representations, and
multimodal large
language models (MLLMs). Our results demonstrate that models using self-supervised representations outperform methods with classical acoustic features, particularly in capturing complex and dynamic impressions (e.g., “Cold–Warm”) where classical features fail. In contrast, current MLLMs prove unreliable for this fine-grained pairwise task. This study provides the first systematic investigation of RIE and demonstrates the strength of self-supervised
speech models in capturing subtle perceptual variations.
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Computation and Language · Cross-listed from cs.LG
Deep Dense Exploration for LLM Reinforcement Learning via Pivot-Driven Resampling
Yiran Guo, Zhongjian Qiao, Yingqi Xie et al. (+5 more)
Effective exploration is a key challenge in reinforcement learning for large
language models: discovering high-quality trajectories within a limited sampling budget from the vast natural
language sequence space. Existing methods face notable limitations: GRPO samples exclusively from the root, saturating high-probability trajectories while leaving deep, error-prone states under-explored. Tree-based methods blindly disperse budgets across trivial or unrecoverable states, causing sampling dilution that fails to uncover rare correct suffixes and destabilizes local baselines. To address this, we propose Deep Dense Exploration (DDE), a strategy that focuses exploration on $\textit{pivots}$-deep, recoverable states within unsuccessful trajectories. We instantiate DDE with DEEP-GRPO, which introduces three key innovations: (1) a lightweight data-driven utility function that automatically balances recoverability and depth bias to identify pivot states; (2) local dense resampling at each pivot to increase the probability of discovering correct subsequent trajectories; and (3) a dual-stream optimization objective that decouples global policy learning from local corrective updates. Experiments on mathematical
reasoning benchmarks demonstrate that our method consistently outperforms GRPO, tree-based methods, and other strong baselines. Code is available at https://github.com/AgentCombo/DEEP-GRPO
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All authors Yiran Guo, Zhongjian Qiao, Yingqi Xie, Jie Liu, Dan Ye, Ruiqing Zhang, Shuang Qiu, Lijie Xu
Computation and Language
Index Light, Reason Deep: Deferred Visual Ingestion for Visual-Dense Document Question Answering
Tao Xu
Existing
multimodal document question answering methods predominantly adopt a Pre-Ingestion (PI) strategy: during the indexing phase, a
Vision Language Model (VLM) is called on every page to generate page descriptions that are then encoded into vectors, and questions are answered via
embedding similarity
retrieval. However, this approach faces a dual dilemma on visual-dense engineering documents: VLM blind descriptions inevitably lose critical visual details, and
embedding retrieval systematically fails on highly similar documents. This paper proposes the Deferred Visual Ingestion (DVI) framework: zero VLM calls during preprocessing, leveraging only document structural information (table of contents, drawing numbers) to automatically build a hierarchical index through the HDNC (Hierarchical Drawing Number Clustering)
algorithm; during inference, candidate pages are located via BM25
retrieval, and the original images along with the specific question are sent to a VLM for targeted analysis. Large-scale experiments on three
datasets validate the effectiveness of DVI: on Bridge engineering drawings (1,323 questions), end-to-end QA accuracy reaches 65.6% vs. PI's 24.3% (+41.3pp); on Steel catalog (186 questions), 30.6% vs. 16.1% (+14.5pp); on CircuitVQA, a public
benchmark (9,315 questions),
retrieval ImgR@3 achieves 31.2% vs. 0.7%. On the Bridge
dataset, we evaluated ColPali (ICLR 2025 visual
retrieval SOTA), which achieved only 20.1% PageR@3, demonstrating that the failure of
embedding retrieval on homogeneous engineering documents is structural rather than due to insufficient model capability. Ablation studies show that HDNC zero-cost automatic indexing yields a +27.5pp
retrieval improvement, and VLM conversion rate analysis confirms that the bottleneck lies on the
retrieval side rather than the comprehension side.
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Computation and Language
A Multi-Agent Framework for Medical AI: Leveraging Fine-Tuned GPT, LLaMA, and DeepSeek R1 for Evidence-Based and Bias-Aware Clinical Query Processing
Naeimeh Nourmohammadi, Md Meem Hossain, The Anh Han et al. (+2 more)
Large
language models (LLMs) show promise for healthcare question answering, but clinical use is limited by weak verification, insufficient evidence grounding, and unreliable confidence signalling. We propose a multi-
agent medical QA framework that combines complementary LLMs with evidence
retrieval, uncertainty estimation, and bias checks to improve answer reliability. Our approach has two phases. First, we fine-tune three representative LLM families (GPT, LLaMA, and DeepSeek R1) on MedQuAD-derived medical QA data (20k+ question-answer pairs across multiple NIH domains) and
benchmark generation quality. DeepSeek R1 achieves the strongest scores (ROUGE-1 0.536 +- 0.04; ROUGE-2 0.226 +-0.03; BLEU 0.098 -+ 0.018) and substantially outperforms the specialised biomedical baseline BioGPT in zero-shot evaluation. Second, we implement a modular multi-
agent pipeline in which a Clinical
Reasoning agent (fine-tuned LLaMA) produces structured explanations, an Evidence
Retrieval agent queries PubMed to ground responses in recent literature, and a Refinement
agent (DeepSeek R1) improves clarity and factual consistency; an optional human validation path is triggered for high-risk or high-uncertainty cases. Safety mechanisms include Monte Carlo dropout and perplexity-based uncertainty scoring, plus lexical and sentiment-based bias detection supported by LIME/SHAP-based analyses. In evaluation, the full system achieves 87% accuracy with relevance around 0.80, and evidence augmentation reduces uncertainty (perplexity 4.13) compared to base responses, with mean end-to-end latency of 36.5 seconds under the reported configuration. Overall, the results indicate that
agent specialisation and verification layers can mitigate key single-model limitations and provide a practical, extensible design for evidence-based and bias-aware medical AI.
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All authors Naeimeh Nourmohammadi, Md Meem Hossain, The Anh Han, Safina Showkat Ara, Zia Ush Shamszaman
Computation and Language · Cross-listed from cs.LG
Watch the Model Think: On-Policy Extraction of Activation Steering Vectors
Xuanbo Su, Yingfang Zhang, Hao Luo et al. (+3 more)
When a model solves a problem on one attempt and fails it on the next, what separates the two is rarely the final answer
token; it is the trajectory that reached it. Contrastive activation steering leaves that signal unused: CAA, SADI, RepE and ITI build their direction from experimenter-supplied text, recorded while the model reads rather than reasons. That choice also caps what the vector can express, since polarity must be written into the text, and a task judged only by outcome offers nothing to write it with. ROAST makes the trajectory itself the contrast: sample rollouts, let an outcome verifier split them into successes and failures, and contrast the
reasoning that worked against the
reasoning that did not. A matched teacher-forced control—rollouts, labels, answer text and pair counts held fixed, the trajectory alone stripped—points to the trajectory as what matters: on GSM8K at 0.6B the pairs alone buy +0.12 points while restoring the trajectories buys +6.05, the larger and only seed-robust step. Replacing the trajectory with an equal-length neutral prefix or another question's
reasoning falls below no intervention. The two corpora are also far apart geometrically, a median 70+ degrees apart at both Qwen3 scales probed, beyond what a split-half null explains. Reading from rollouts calls for two corrections—keeping the full difference vector rather than Top-10% masking, and giving each question one vote rather than one per pair—and only grouped aggregation beats the unsteered baseline under 20% verifier noise. On parser-free
benchmarks (GSM8K, MATH500, IFEval), ROAST is best in all six
cells over two models, by up to +9.7, at +6.4% wall-clock and no added context; it also leads on six parser-scored
benchmarks across three models. Across nine models (0.6B–122B, four families), ROAST improves on the unsteered model at every scale. Code: https://github.com/TomySu404/ORBIT
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All authors Xuanbo Su, Yingfang Zhang, Hao Luo, Huajun Bai, Guangyuan Dong, Ling Huang
Computation and Language · Cross-listed from cs.AI
Algebraic Quantum Intelligence: A New Framework for Reproducible Machine Creativity
Kazuo Yano, Jonghyeok Lee, Tae Ishitomi et al. (+26 more)
Large
language models (LLMs) have achieved remarkable success in generating fluent and contextually appropriate text; however, their capacity to produce genuinely creative outputs remains limited. This paper posits that this limitation arises from a structural property of contemporary LLMs: when provided with rich context, the space of future generations becomes strongly constrained, and the generation process is effectively governed by near-deterministic dynamics. Recent approaches such as test-time scaling and context adaptation improve performance but do not fundamentally alter this constraint. To address this issue, we propose Algebraic
Quantum Intelligence (AQI) as a computational framework that enables systematic expansion of semantic space. AQI is formulated as a noncommutative algebraic structure inspired by
quantum theory, allowing properties such as order dependence, interference, and uncertainty to be implemented in a controlled and designable manner. Semantic states are represented as vectors in a
Hilbert space, and their
evolution is governed by C-values computed from noncommutative operators, thereby ensuring the coexistence and expansion of multiple future semantic possibilities. In this study, we implement AQI by extending a
transformer-based LLM with more than 600 specialized operators. We evaluate the resulting system on creative
reasoning benchmarks spanning ten domains under an LLM-as-a-judge protocol. The results show that AQI consistently outperforms strong baseline models, yielding statistically significant improvements and reduced cross-domain variance. These findings demonstrate that noncommutative algebraic dynamics can serve as a practical and reproducible foundation for machine creativity. Notably, this architecture has already been deployed in real-world enterprise environments.
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All authors Kazuo Yano, Jonghyeok Lee, Tae Ishitomi, Hironobu Kawaguchi, Akira Koyama, Masakuni Ota, Yuki Ota, Nobuo Sato, Keita Shimada, Sho Takematsu, Ayaka Tobinai, Satomi Tsuji, Kazunori Yanagi, Keiko Yano, Manabu Harada, Yuki Matsuda, Kazunori Matsumoto, Kenichi Matsumura, Hamae Matsuo, Yumi Miyazaki, Kotaro Murai, Tatsuya Ohshita, Marie Seki, Shun Tanoue, Tatsuki Terakado, Yuko Ichimaru, Mirei Saito, Akihiro Otsuka, Koji Ara
Computation and Language
Character-aware Transformers Learn an Irregular Morphological Pattern Yet None Generalize Like Humans
Akhilesh Kakolu Ramarao, Kevin Tang and Dinah Baer-Henney
Whether neural networks can serve as cognitive models of morphological learning remains an open question. Recent work has shown that encoder-decoder models can acquire irregular patterns, but evidence that they generalize these patterns like humans is mixed. We investigate this using the Spanish L-shaped morphome, where only the first-person singular indicative (e.g., pongo `I put') shares its stem with all subjunctive forms (e.g., ponga, pongas) despite lacking apparent phonological, semantic, or syntactic motivation. We compare five encoder-decoder
transformers varying along two dimensions: sequential vs. position-invariant positional encoding, and atomic vs. decomposed tag representations. Positional encoding proves decisive: position-invariant models recover the correct L-shaped paradigm clustering even when L-shaped verbs are scarce in training, whereas sequential positional encoding models only partially capture the pattern. Yet none of the models productively generalize this pattern to novel forms. Position-invariant models generalize the L-shaped stem across subjunctive
cells but fail to extend it to the first-person singular indicative, producing a mood-based generalization rather than the L-shaped morphomic pattern. Humans do the opposite, generalizing preferentially to the first-person singular indicative over subjunctive forms. None of the models reproduce the human pattern, highlighting the gap between statistical pattern reproduction and morphological abstraction.
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Computation and Language
CCiV: A Benchmark for Structure, Rhythm and Quality in LLM-Generated Chinese Ci Poetry
Shangqing Zhao, Yupei Ren, Yuhao Zhou et al. (+2 more)
The generation of classical Chinese Ci poetry, a form demanding a sophisticated blend of structural
rigidity, rhythmic harmony, and artistic quality, poses a significant challenge for large
language models (LLMs). To systematically evaluate and advance this capability, we introduce Chinese Cipai Variants (CCiV), a
benchmark designed to assess LLM-generated Ci poetry across these three dimensions: structure, rhythm, and quality. Our evaluation of 17 LLMs on 30 Cipai reveals two critical phenomena: models frequently generate valid but unexpected historical variants of a poetic form, and adherence to tonal patterns is substantially harder than structural rules. We further show that form-aware prompting can improve structural and tonal control for stronger models, while potentially degrading weaker ones. Finally, we observe weak and inconsistent
alignment between formal correctness and literary quality in our sample. CCiV highlights the need for variant-aware evaluation and more holistic constrained creative generation methods.
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All authors Shangqing Zhao, Yupei Ren, Yuhao Zhou, Xiaopeng Bai, Man Lan
Computation and Language
Empty Shelves or Lost Keys? Recall Is the Bottleneck for Parametric Factuality
Nitay Calderon, Eyal Ben-David, Zorik Gekhman et al. (+2 more)
Standard factuality evaluations of LLMs treat all errors alike, obscuring whether failures arise from missing knowledge (empty shelves) or from limited access to encoded facts (lost keys). We propose a behavioral framework that profiles factual knowledge at the level of facts rather than questions, characterizing each fact by whether it is encoded, and then by how accessible it is: cannot be recalled, can be directly recalled, or can only be recalled with inference-time computation (thinking). To support such profiling, we introduce WikiProfile, a new
benchmark constructed via an automated pipeline with a prompted LLM grounded in web search. Across 4 million responses from 13 LLMs, we find that encoding is nearly saturated in frontier models on our
benchmark, with GPT-5 and Gemini-3 encoding 95–98% of facts. However, recall remains a major bottleneck: many errors previously attributed to missing knowledge instead stem from failures to access it. These failures are systematic and disproportionately affect long-tail facts and reverse questions. Finally, we show that thinking improves recall and can recover a substantial fraction of failures, indicating that future gains may rely less on scaling and more on methods that improve how models utilize what they already encode.
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All authors Nitay Calderon, Eyal Ben-David, Zorik Gekhman, Eran Ofek, Gal Yona
Computation and Language
GTS: Inference-Time Scaling of Latent Reasoning with a Learnable Gaussian Thought Sampler
Minghan Wang, Ye Bai, Thuy-Trang Vu et al. (+2 more)
Inference-time scaling (ITS) in latent
reasoning models typically relies on heuristic perturbations, such as dropout or fixed Gaussian noise, to generate diverse candidate trajectories. However, we show that stronger perturbations do not necessarily yield better sampling quality: they often induce larger distribution shifts without producing more useful
reasoning paths or better final decisions. A key limitation is that these perturbations inject stochasticity without defining an explicit conditional sampling distribution, making latent exploration difficult to control or optimize. To address this, we propose the Gaussian Thought Sampler (GTS), a lightweight module that reformulates latent exploration as sampling from a learned conditional distribution over continuous
reasoning states. GTS predicts context-dependent perturbation distributions and is trained with GRPO-style policy optimization while keeping the backbone frozen, turning heuristic perturbation into an explicit probabilistic sampling policy. Experiments across multiple
benchmarks and two latent
reasoning architectures show that GTS yields more reliable inference-time scaling than heuristic baselines, suggesting that effective latent ITS requires better-controlled and optimizable sampling rather than simply amplifying stochasticity.
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All authors Minghan Wang, Ye Bai, Thuy-Trang Vu, Ehsan Shareghi, Gholamreza Haffari
Computation and Language
Annotation-Efficient Vision-Language Model Adaptation to the Polish Language Using the LLaVA Framework
Grzegorz Statkiewicz, Alicja Dobrzeniecka, Karolina Seweryn et al. (+5 more)
Most
vision-
language models (VLMs) are trained on English-centric data, limiting their performance in other
languages and cultural contexts. This restricts their usability for non-English-speaking users and hinders the development of
multimodal systems that reflect diverse linguistic and cultural realities. In this work, we reproduce and adapt the LLaVA-Next methodology to create a set of Polish VLMs. We rely on a fully automated pipeline for translating and filtering existing
multimodal datasets, and complement this with synthetic Polish data for OCR and culturally specific tasks. Despite relying almost entirely on automatic translation and minimal manual intervention to the training data, our approach yields strong results: we observe a +9.5% improvement over LLaVA-1.6-Vicuna-13B on a Polish-adapted MMBench, along with higher-quality captions in generative evaluations, as measured by human annotators in terms of linguistic correctness. These findings highlight that large-scale automated translation, combined with lightweight filtering, can effectively bootstrap high-quality
multimodal models for low-resource
languages. Some challenges remain, particularly in cultural coverage and evaluation. To facilitate further research, we make our models and evaluation
dataset publicly available.
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All authors Grzegorz Statkiewicz, Alicja Dobrzeniecka, Karolina Seweryn, Aleksandra Krasnodębska, Karolina Piosek, Katarzyna Bogusz, Sebastian Cygert, Wojciech Kusa
Computation and Language
Open Rubric System: Scaling Reinforcement Learning with Pairwise Adaptive Rubric
Ruipeng Jia, Yunyi Yang, Wen Wang et al. (+7 more)
Scalar reward models compress multi-dimensional human preferences into a single opaque score, creating an information bottleneck that often leads to brittleness and reward hacking in open-ended
alignment. We argue that robust
alignment for non-verifiable tasks is fundamentally a principle generalization problem: reward should not be a learned function internalized into a judge, but an explicit
reasoning process executed under inspectable principles. To operationalize this view, we present the Open Rubric System (OpenRS), a plug-and-play, rubrics-based LLM-as-a-Judge framework built around Pairwise Adaptive Meta-Rubrics (PAMR) and lightweight Pointwise Verifiable Rubrics (PVRs), which provide both hard-constraint guardrails and verifiable reward components when ground-truth or programmatic checks are available. OpenRS uses an explicit meta-rubric – a constitution-like specification that governs how rubrics are instantiated, weighted, and enforced – and instantiates adaptive rubrics on the fly by conditioning on the semantic differences between two candidate responses. It then performs criterion-wise pairwise comparisons and aggregates criterion-level preferences externally, avoiding pointwise weighted scalarization while improving discriminability in open-ended settings. To keep principles consistent yet editable across various domains, we introduce a two-level meta-rubric refinement pipeline (automated evolutionary refinement for general principles and a reproducible human-in-the-loop procedure for domain principles), complemented with pointwise verifiable rubrics that act as both guardrails against degenerate behaviors and a source of verifiable reward for objective sub-tasks. Finally, we instantiate OpenRS as reward supervision in pairwise RL training.
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All authors Ruipeng Jia, Yunyi Yang, Wen Wang, Yuxin Wu, Yongbo Gai, Siyuan Tao, Mengyu Zhou, Jianhe Lin, Xiaoxi Jiang, Guanjun Jiang
Computation and Language
From Scarcity to Scale: A Release-Level Analysis of the Pashto Common Voice Dataset
Jandad Jahani, Mursal Dawodi and Jawid Ahmad Baktash
Large, openly licensed
speech datasets are essential for building automatic
speech recognition (ASR) systems, yet many widely spoken
languages remain underrepresented in public resources. Pashto, spoken by more than 60 million people, has historically lacked large-scale openly licensed
speech data suitable for modern ASR development. This paper presents a release-level analysis of the Pashto component of the Mozilla Common Voice corpus, focusing on version 24.0 (December 2025) and contextualizing trends across major releases. We document rapid growth from 1.49 recorded hours in mid-2023 to 2,768.7 total hours in 2025, including 975.89 validated hours available for supervised ASR training. Beyond scale, we analyze validation throughput, contributor participation inequality, demographic metadata completeness, and sentence-level concentration in the validated subset. We find that participation is extremely concentrated (Gini = 0.941), age representation is strongly skewed toward young adults, and 41.97% of clips lack self-reported gender labels, limiting subgroup
auditing based on metadata. At the textual level,
prompt reuse is moderate: 35.88% of unique sentences account for 50% of validated clips, suggesting that structural concentration is driven primarily by uneven contributor activity rather than dominance of a small
prompt set. These results provide a quantitative audit of a rapidly scaling low-resource
speech corpus and highlight practical priorities for improving
dataset maturity, including expanded validation capacity and broader demographic participation.
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Computation and Language
LM-Lexicon: Improving Definition Modeling via Harmonizing Semantic Experts
Yang Liu, Jiaye Yang, Weikang Li et al. (+3 more)
We introduce LM-Lexicon, an innovative definition modeling approach that incorporates data clustering, semantic expert learning, and model merging using a sparse mixture-of-experts architecture. By decomposing the definition modeling task into specialized semantic domains, where small
language models are trained as domain experts, LM-Lexicon achieves substantial improvements (+7% BLEU score compared with the prior state-of-the-art model) over existing methods on five widely used
benchmarks. Empirically, we demonstrate that 1) the clustering strategy enables fine-grained expert specialization with nearly 10% improvement in definition quality; 2) the semantic-aware domain-level routing mechanism achieves higher expert efficacy (+1%) than conventional
token-level routing; and 3) further performance gains can be obtained through test-time compute and semantic expert scaling. Our work advances definition modeling while providing insights into the development of efficient
language models for semantic-intensive applications.
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All authors Yang Liu, Jiaye Yang, Weikang Li, Jiahui Liang, Yang Li, Lingyong Yan
Computation and Language
LogitsCoder: Towards Efficient Chain-of-Thought Path Search via Logits Preference Decoding for Code Generation
Jizheng Chen, Weiming Zhang, Xinyi Dai et al. (+6 more)
Code generation remains a challenging task that requires precise and structured
reasoning. Existing Test Time Scaling (TTS) methods, including structured tree search, have made progress in exploring
reasoning paths but still face two major challenges: (1) underthinking, where
reasoning chains tend to be shallow and fail to capture the full complexity of problems; and (2) overthinking, where overly verbose
reasoning leads to inefficiency and increased computational costs. To address these issues, we propose LogitsCoder, a novel framework that enhances chain-of-thought
reasoning through lightweight, logit-level control mechanisms for code generation. LogitsCoder iteratively generates and refines
reasoning steps by first steering
token selection toward statistically preferred patterns via Logits Preference Decoding, then selecting and aggregating diverse
reasoning paths using Logits Rank Based Path Selection and Thoughts Aggregation. This results in coherent and effective
reasoning chains that balance depth and efficiency. Extensive experiments demonstrate that LogitsCoder produces more efficient and higher-quality
reasoning chains, leading to superior code generation performance compared to baseline methods.
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All authors Jizheng Chen, Weiming Zhang, Xinyi Dai, Weiwen Liu, Kounianhua Du, Yasheng Wang, Ruiming Tang, Yong Yu, Weinan Zhang
Computation and Language
Context Shapes LLMs Retrieval-Augmented Fact-Checking Effectiveness
Pietro Bernardelle, Stefano Civelli, Kevin Roitero et al. (+1 more)
Large
language models (LLMs) show strong
reasoning abilities across diverse tasks, yet their performance on extended contexts remains inconsistent. While prior research has emphasized mid-context degradation in question answering, this study examines the impact of context in LLM-based fact verification. Using three
datasets (HOVER, FEVEROUS, and ClimateFEVER) and five open-source models accross different parameters sizes (7B, 32B and 70B parameters) and model families (Llama-3.1, Qwen2.5 and Qwen3), we evaluate both parametric factual knowledge and the impact of evidence placement across varying context lengths. We find that LLMs exhibit non-trivial parametric knowledge of factual claims and that their verification accuracy generally declines as context length increases. Similarly to what has been shown in previous works, in-context evidence placement plays a critical role with accuracy being consistently higher when relevant evidence appears near the beginning or end of the
prompt and lower when placed mid-context. These results underscore the importance of
prompt structure in
retrieval-augmented fact-checking systems.
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All authors Pietro Bernardelle, Stefano Civelli, Kevin Roitero, Gianluca Demartini
Computation and Language
Geometry-Preserving Aggregation for Mixture-of-Experts Embedding Models
Sajjad Kachuee and Mohammad Sharifkhani
Mixture-of-Experts (MoE)
embedding models combine expert outputs using weighted linear summation, implicitly assuming a linear subspace structure in the
embedding space. This assumption is shown to be inconsistent with the geometry of expert representations.
Geometric analysis of a modern MoE
embedding model reveals that expert outputs lie on a shared hyperspherical
manifold characterized by tightly concentrated norms and substantial angular separation. Under this geometry, linear aggregation induces inward collapse toward the
manifold interior, distorting vector magnitude and direction and reducing
embedding comparability. To address this inconsistency, Spherical Barycentric Aggregation (SBA) is introduced as a geometry-preserving aggregation operator that separates radial and angular components to maintain hyperspherical structure while remaining fully compatible with existing routing mechanisms. Experiments on selected tasks from the Massive Text
Embedding Benchmark (MTEB), including semantic similarity, clustering, and duplicate question detection, demonstrate consistent performance improvements with identical training cost and full stability. Additional
geometric analyses confirm that SBA prevents aggregation-induced collapse and preserves hyperspherical consistency, highlighting the importance of geometry-aware aggregation in MoE
embedding architectures.
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Computation and Language
GRRM: Group Relative Reward Modeling for Machine Translation
Sen Yang, Shanbo Cheng, Lu Xu et al. (+2 more)
While Group Relative Policy Optimization (GRPO) offers a powerful framework for LLM post-training, its effectiveness in open-ended domains like Machine Translation hinges on accurate intra-group ranking. We identify that standard Pointwise Quality Metrics (PQM) fall short in this context: candidates are evaluated in isolation, so the comparative context is missing for distinguishing fine-grained linguistic nuances. To address this, we introduce the Group Quality Metric (GQM) paradigm and its instantiation, the Group Relative Reward Model (GRRM). Unlike traditional independent scorers, GRRM jointly processes the entire candidate group, leveraging comparative analysis to rigorously resolve relative quality and adaptive granularity. Empirical evaluations confirm that GRRM achieves competitive ranking accuracy among all baselines; integrating GRRM into the GRPO training not only improves general translation quality but also unlocks
reasoning capabilities comparable to state-of-the-art
reasoning models. We release codes,
datasets, and model checkpoints at https://github.com/NJUNLP/GRRM.
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All authors Sen Yang, Shanbo Cheng, Lu Xu, Jianbing Zhang, Shujian Huang
Computation and Language
Named Entity Recognition for Payment Data Using NLP
Srikumar Nayak
Named Entity Recognition (NER) has emerged as a critical component in automating financial transaction processing, particularly in extracting structured information from unstructured payment data. This paper presents a comprehensive analysis of state-of-the-art NER
algorithms specifically designed for payment data extraction, including Conditional Random Fields (CRF), Bidirectional Long Short-Term
Memory with CRF (BiLSTM-CRF), and
transformer-based models such as BERT and FinBERT. We conduct extensive experiments on a
dataset of 50,000 annotated payment transactions across multiple payment formats including SWIFT MT103, ISO 20022, and domestic payment systems. Our experimental results demonstrate that fine-tuned BERT models achieve an F1-score of 94.2% for entity extraction, outperforming traditional CRF-based approaches by 12.8 percentage points. Furthermore, we introduce PaymentBERT, a novel hybrid architecture combining domain-specific financial
embeddings with contextual representations, achieving state-of-the-art performance with 95.7% F1-score while maintaining real-time processing capabilities. We provide detailed analysis of cross-format generalization, ablation studies, and deployment considerations. This research provides practical insights for financial institutions implementing automated sanctions screening, anti-money laundering (AML) compliance, and payment processing systems.
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Computation and Language
The Sufficiency-Conciseness Trade-off in LLM Self-Explanation from an Information Bottleneck Perspective
Ali Zahedzadeh and Behnam Bahrak
Large
Language Models increasingly rely on self-explanations, such as chain of thought
reasoning, to improve performance on multi step question answering. While these explanations enhance accuracy, they are often verbose and costly to generate, raising the question of how much explanation is truly necessary. In this paper, we examine the trade-off between sufficiency, defined as the ability of an explanation to justify the correct answer, and conciseness, defined as the reduction in explanation length. Building on the information bottleneck principle, we conceptualize explanations as compressed representations that retain only the information essential for producing correct answers.To operationalize this view, we introduce an evaluation pipeline that constrains explanation length and assesses sufficiency using multiple
language models on the ARC Challenge
dataset. To broaden the scope, we conduct experiments in both English, using the original
dataset, and Persian, as a resource-limited
language through translation. Our experiments show that more concise explanations often remain sufficient, preserving accuracy while substantially reducing explanation length, whereas excessive compression leads to performance degradation.
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Computation and Language
Chain-of-Thought Reasoning with Large Language Models for Clinical Alzheimer's Disease Assessment and Diagnosis
Tongze Zhang, Jun-En Ding, Melik Ozolcer et al. (+5 more)
Alzheimer's disease (AD) has become a prevalent neurodegenerative disease worldwide. Traditional diagnosis still relies heavily on medical imaging and clinical assessment by physicians, which is often time-consuming and resource-intensive in terms of both human expertise and healthcare resources. In recent years, large
language models (LLMs) have been increasingly applied to the medical field using electronic health records (EHRs), yet their application in Alzheimer's disease assessment remains limited, particularly given that AD involves complex multifactorial etiologies that are difficult to observe directly through imaging modalities. In this work, we propose leveraging LLMs to perform Chain-of-Thought (CoT)
reasoning on patients' clinical EHRs. Unlike direct fine-tuning of LLMs on EHR data for AD classification, our approach utilizes LLM-generated CoT
reasoning paths to provide the model with explicit diagnostic rationale for AD assessment, followed by structured CoT-based predictions. This pipeline not only enhances the model's ability to diagnose intrinsically complex factors but also improves the interpretability of the prediction process across different stages of AD progression. Experimental results demonstrate that the proposed CoT-based diagnostic framework significantly enhances stability and diagnostic performance across multiple CDR grading tasks, achieving up to a 15% improvement in F1 score compared to the zero-shot baseline method.
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All authors Tongze Zhang, Jun-En Ding, Melik Ozolcer, Fang-Ming Hung, Albert Chih-Chieh Yang, Feng Liu, Yi-Rou Ji, Sang Won Bae