Computation and Language · Cross-listed from cs.CY
Tracing the Evolution of Word Embedding Techniques in Natural Language Processing
Minh Anh Nguyen, Kuheli Sai and Minh Nguyen
This work traces the
evolution of word-
embedding techniques within the natural
language processing (NLP) literature. We collect and analyze 149 research articles spanning the period from 1954 to 2025, providing both a comprehensive methodological review and a data-driven bibliometric analysis of how representation learning has developed over seven decades. Our study covers four major
embedding paradigms, statistical representation-based methods (one-hot encoding, bag-of-words, TF-IDF), static word
embeddings (Word2Vec, GloVe, FastText), contextual word
embeddings (ELMo, BERT, GPT), and sentence/document
embeddings, critically discussing the strengths, limitations, and intellectual lineage connecting each category. Beyond the methodological survey, we conduct a formal era comparison using GPT-3's release as a dividing line, applying seven hypothesis tests to quantify shifts in research focus, collaboration patterns, and institutional involvement. Our analysis reveals a dramatic post-GPT-3 paradigm shift: contextual and sentence-level methods now dominate at 6.4X the odds of the pre-GPT-3 era, mean team sizes have grown significantly (p = 0.018), and 30 entirely new techniques have emerged while 54 pre-GPT-3 methods received no further
attention. These findings, combined with evidence of rising industry involvement, provide a quantitative account of how the field's epistemic priorities have been reshaped by the advent of large
language models.
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Computation and Language · Cross-listed from cs.MM
Omni-C: Compressing Heterogeneous Modalities into a Single Dense Encoder
Kin Wai Lau, Yasar Abbas Ur Rehman, Lai-Man Po et al. (+1 more)
Recent
multimodal systems often rely on separate expert modality encoders which cause linearly scaling complexity and computational overhead with added modalities. While unified Omni-models address this via Mixture-of-Expert (MoE) architectures with specialized experts and routing, they still inflate parameter counts and introduce routing overhead. In this paper, we propose Omni-C (Omni-Compress), a single dense
Transformer-based encoder that learns competitive shared representations across heterogeneous modalities–images, audio, and text–through unimodal contrastive pretraining on large-scale unaligned data. By maximizing parameter sharing in the backbone and using lightweight modality-specific projection heads, Omni-C effectively mitigates inter-modality conflicts without requiring MoE, paired supervision, or routing. This design supports efficient deployment on
memory-constrained systems via sequential modality processing and low-
memory inference, eliminating the need for parallel expert loading or specialized hardware. Experiments show Omni-C achieves performance comparable to expert models in unimodal and cross-model tasks, with modest zero-shot degradation on audio and text that is largely recovered through lightweight linear probing or parameter efficient fine-tuning. The unified architecture substantially reduces inference
memory usage compared to multi-encoder baselines, advancing efficient and scalable
multimodal learning.
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All authors Kin Wai Lau, Yasar Abbas Ur Rehman, Lai-Man Po, Pedro Porto Buarque de Gusmão
Computation and Language
Query Disambiguation via Answer-Free Context: Doubling Performance on Humanity's Last Exam
Michael Majurski and Cynthia Matuszek
How carefully and unambiguously a question is phrased has a profound impact on the quality of the response, for
Language Models (LMs) as well as people. While model capabilities continue to advance, the interplay between grounding context and query formulation remains under-explored. This work investigates how the quality of background grounding information in a model's context window affects accuracy. We find that combining well-grounded dynamic context construction (i.e, RAG) with query rewriting reduces question ambiguity, resulting in significant accuracy gains. Given a user question with associated answer-free grounding context, rewriting the question to reduce ambiguity produces
benchmark improvements without changing the answer itself, even compared to prepending that context before the question. Using gpt-oss-20b to rewrite a subset of Humanity's Last Exam using answer-free grounding context improves gpt-5-mini accuracy from 0.14 to 0.37. We demonstrate that this accuracy improvement cannot be fully recovered just through prompting at inference time; rather, distinct rewriting and answering phases are required. Code and data are available at https://github.com/mmajurski/lm-rewrite-uplift
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Computation and Language
Induced Numerical Instability: Hidden Costs in Multimodal Large Language Models
Wai Tuck Wong, Jun Sun and Arunesh Sinha
The use of
multimodal large
language models has become widespread, and as such the study of these models and their failure points has become of utmost importance. We study a novel mode of failure that causes degradation in performance indirectly by optimizing a loss term that seeks to maximize numerical instability in the inference stage of these models. We apply this loss term as the optimization target to construct images that, when used on
multimodal large
language models, cause significant degradation in the output. We validate our hypothesis on state of the art models large
vision language models (LLaVa-v1.5-7B, Idefics3-8B, SmolVLM-2B-Instruct) against standard
datasets (Flickr30k, MMVet, TextVQA, VQAv2, POPE, COCO) and show that performance degrades significantly, even with a very small change to the input image, compared to baselines. Our results uncover a fundamentally different vector of performance degradation, highlighting a failure mode not captured by
adversarial perturbations.
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Computation and Language
A unified foundational framework for knowledge injection and evaluation of Large Language Models in Combustion Science
Zonglin Yang, Runze Mao, Tianhao Wu et al. (+3 more)
To advance foundation Large
Language Models (LLMs) for combustion science, this study presents the first end-to-end framework for developing domain-specialized models for the combustion community. The framework comprises an AI-ready
multimodal knowledge base at the 3.5 billion-
token scale, extracted from over 200,000 peer-reviewed articles, 8,000 theses and dissertations, and approximately 400,000 lines of combustion CFD code; a rigorous and largely automated evaluation
benchmark (CombustionQA, 436 questions across eight subfields); and a three-stage knowledge-injection pathway that progresses from lightweight
retrieval-augmented generation (RAG) to knowledge-graph-enhanced
retrieval and continued pretraining. We first quantitatively validate Stage 1 (naive RAG) and find a hard ceiling: standard RAG accuracy peaks at 60%, far surpassing zero-shot performance (23%) yet well below the theoretical upper bound (87%). We further demonstrate that this stage's performance is severely constrained by context contamination. Consequently, building a domain foundation model requires structured knowledge graphs and continued pretraining (Stages 2 and 3).
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All authors Zonglin Yang, Runze Mao, Tianhao Wu, Han Li, QingGuo Zhou, Zhi X. Chen
Computation and Language
Universal Conceptual Structure in Neural Translation: Probing NLLB-200's Multilingual Geometry
Kyle Elliott Mathewson
Do
multilingual translation models organize meaning around a shared conceptual space, or do they primarily encode
language identity and surface form? We probe the encoder geometry of Meta's 600M-parameter NLLB-200 model across 135
languages and 101 Swadesh concepts in contextualized carrier-frame and decontextualized bare-word regimes against null and confound controls. First, two-way variance partitioning reveals an additive
language-shift plus conceptual-
manifold geometry:
language shifts account for 45.7% of variance on bare words vs. 13.7% in context, and mean-centering improves the between-to-within-concept distance ratio (vs. a 0.99 permutation null) by 2.14x on bare words (1.15 to 2.46; 2.27x across disjoint scripts) and 1.19x in context (2.25 to 2.69), with conceptual separation peaking at Layer 10 (mutual k-NN overlap jumping 4.35x). Second, semantic category explains 25.4% of Swadesh convergence variance ($F(7,93)=4.53$, $p=2.21\times 10^{-4}$; partial $F=7.74$ controlling for fertility and length)—over 20x orthography or phonology ($R^2\le 0.012$)—while the advantage of Swadesh over non-loanword concrete nouns ($d=0.54$–$0.69$) is mediated by Zipfian subword compactness ($p=7.43\times 10^{-7}$). Third,
language distances track ASJP NLD and LDND phonetic distances within subfamilies under block-permutation and cross-script controls ($\rho_s=0.65$–$0.67$, block $p=10^{-4}$; global bare-word Mantel $\rho_s=0.24$, $p=0.001$), and CLICS$^3$ colexified concepts lie closer across string-distinct, within-category ($\rho_s=0.32$), and bare-word ($d=1.79$) controls ($d=1.43$, $p=1.55\times 10^{-33}$). Finally, basic color terms recover the Berlin and Kay hierarchy ($\rho_s=0.91$–$0.93$, $p\le 2.18\times 10^{-4}$), and semantic offsets exceed distance-matched controls ($p=3.55\times 10^{-5}$, $d=1.06$). We release InterpretCognates, an interactive toolkit and reproducible suite.
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Computation and Language
Policy Compliance of User Requests in Natural Language for AI Systems
Pedro Cisneros-Velarde
Consider an organization whose users send requests in natural
language to an AI system that fulfills them by carrying out specific tasks. In this paper, we consider the problem of ensuring such user requests comply with a list of diverse policies determined by the organization with the purpose of guaranteeing the safe and reliable use of the AI system. We propose, to the best of our knowledge, the first
benchmark consisting of annotated user requests of diverse compliance with respect to a list of policies. Our
benchmark is related to industrial applications in the technology sector. We then use our
benchmark to evaluate the performance of various LLM models on policy compliance assessment under different solution methods. We analyze the differences on performance metrics across the models and solution methods, showcasing the challenging nature of our problem.
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Computation and Language
Distribution-Aware Companding Quantization of Large Language Models
Athul Radhakrishnan, Siddhant Mohan and Mahima Sachdeva
Large
language models such as GPT and Llama are trained with a next-
token prediction loss. In this work, we suggest that training
language models to predict multiple future
tokens at once results in higher sample efficiency. More specifically, at each position in the training corpus, we ask the model to predict the following n
tokens using n independent output heads, operating on top of a shared model trunk. Considering multi-
token prediction as an auxiliary training task, we measure improved downstream capabilities with no overhead in training time for both code and natural
language models. The method is increasingly useful for larger model sizes and keeps its appeal when training for multiple epochs. Gains are especially pronounced on generative
benchmarks like coding, where our models consistently outperform strong baselines by several percentage points. Our 13B parameter models solves 12 % more problems on HumanEval and 17 % more on MBPP than comparable next-
token models. Experiments on small algorithmic tasks demonstrate that multi-
token prediction is favorable for the development of induction heads and algorithmic
reasoning capabilities. As an additional benefit, models trained with 4-
token prediction are up to 3X times faster at inference, even with large batch sizes.
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Computation and Language
How Large Language Models Get Stuck: Early structure with persistent errors
Alokesh Manna, William Snyder and Whitney Tabor
Linguistic insights may help make Large
Language Model (LLM) training more efficient. We trained Meta's OPT model on the 100M word BabyLM
dataset, and evaluated it on the BLiMP
benchmark, which consists of 67 classes, each defined by sentence pairs that differ in a targeted syntactic or semantic rule violation. We tested the model's preference for grammatical over ungrammatical sentences across training iterations and grammatical types. In nearly one-third of the BLiMP classes, OPT fails to consistently assign a higher likelihood to grammatical sentences, even after extensive training. When it fails, it often establishes a clear (erroneous) separation of the likelihoods at an early stage of processing and sustains this to the end of our training phase. We hypothesize that this mis-categorization is costly because it creates entrenched biases that must, eventually, be reversed in order for the model to perform well. We probe this phenomenon using a mixture of qualitative (based on linguistic theory and the theory of Deep Learning) and quantitative (based on numerical testing) assessments. Our qualitative assessments indicate that only some BLiMP tests are meaningful guides. We conclude by articulating a hypothesis, the Bigram Hypothesis, which claims that the learning process will exhibit erroneous entrenchment if bigram statistics bias the model toward wrong distinctions early in training, and we describe a method of testing the hypothesis on appropriately selected BLiMP classes.
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Computation and Language
When Metrics Disagree: Automatic Similarity vs. LLM-as-a-Judge for Clinical Dialogue Evaluation
Bian Sun, Zhenjian Wang, Orvill de la Torre et al. (+1 more)
As Large
Language Models (LLMs) are increasingly integrated into healthcare to address complex inquiries, ensuring their reliability remains a critical challenge. Recent studies have highlighted that generic LLMs often struggle in clinical contexts, occasionally producing misleading guidance. To mitigate these risks, this research focuses on the domain-specific adaptation of Llama-2-7B using the Low-Rank Adaptation (LoRA) technique. By injecting trainable low-rank
matrices into the
Transformer layers, we efficiently adapted the model using authentic patient-physician transcripts while preserving the foundational knowledge of the base model. Our objective was to enhance precision and contextual relevance in responding to medical queries by capturing the specialized nuances of clinical discourse. Due to the resource-intensive nature of large-scale human validation, the model's performance was evaluated through a dual-track framework: Track A utilized traditional lexical similarity metrics (e.g., BLEU, ROUGE), while Track B employed an "LLM-as-a-Judge" paradigm using GPT-4 for semantic assessment. Our results demonstrate that while the LoRA-enhanced model achieved significant improvements across all quantitative lexical dimensions, a profound disagreement surfaced in the GPT-4 evaluation, which marginally favored the baseline model's conversational flow. This metric divergence underscores a pivotal finding: traditional automated scores may not fully reflect clinical utility. Consequently, we propose that while automated metrics and LLM judges serve as valuable developmental proxies, rigorous validation by human medical experts remains an indispensable requirement for the safe deployment of LLMs in healthcare settings.
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All authors Bian Sun, Zhenjian Wang, Orvill de la Torre, Zirui Wang
Computation and Language
From Prerequisites to Predictions: Validating a Geometric Hallucination Taxonomy Through Controlled Induction
Matic Korun
We test whether a
geometric hallucination taxonomy – classifying failures as center-drift (Type~1), wrong-well convergence (Type~2), or coverage gaps (Type~3) – can distinguish
hallucination types through controlled induction in GPT-2. Using a two-level statistical design with
prompts ($N = 15$/group) as the unit of inference, we run each experiment 20 times with different generation seeds to quantify result stability. In static
embeddings, Type~3 norm separation is robust (significant in 18/20 runs, Holm-corrected in 14/20, median $r = +0.61$). In contextual hidden states, the Type~3 norm effect direction is stable (19/20 runs) but underpowered at $N = 15$ (significant in 4/20, median $r = -0.28$). Types~1 and~2 do not separate in either space (${\leq}\,3/20$ runs).
Token-level tests inflate significance by 4–16$\times$ through pseudoreplication – a finding replicated across all 20 runs. The results establish coverage-gap
hallucinations as the most geometrically distinctive failure mode, carried by magnitude rather than direction, and confirm the Type~1/2 non-separation as genuine at 124M parameters.
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Computation and Language
Stepwise Penalization for Length-Efficient Chain-of-Thought Reasoning
Xintong Li, Sha Li, Rongmei Lin et al. (+10 more)
Large
reasoning models improve with more test-time computation, but often overthink, producing unnecessarily long chains-of-thought that raise cost without improving accuracy. Prior reinforcement learning approaches typically rely on a single outcome reward with trajectory-level length penalties, which cannot distinguish essential from redundant
reasoning steps and therefore yield blunt compression. Although recent work incorporates step-level signals, such as offline
pruning, supervised data construction, or verifier-based intermediate rewards,
reasoning length is rarely treated as an explicit step-level optimization objective during RL. We propose Step-wise Adaptive Penalization (SWAP), a fine-grained framework that allocates length reduction across steps based on intrinsic contribution. We estimate step importance from the model's on-policy log-probability improvement toward the correct answer, then treat excess length as a penalty mass redistributed to penalize low-importance steps more heavily while preserving high-importance
reasoning. We optimize with a unified outcome-process advantage within group-relative policy optimization. Extensive experiments demonstrate that SWAP reduces
reasoning length by 64.3% on average while improving accuracy by 5.7% relative to the base model.
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All authors Xintong Li, Sha Li, Rongmei Lin, Hongye Jin, Linwei Li, Hejie Cui, Sarah Zhang, Chia-Yuan Chang, Kewei Cheng, Besnik Fetahu, Priyanka Nigam, Jingbo Shang, Bing Yin
Computation and Language · Cross-listed from cs.IR
LLMs Remember First, Forget Last: Dual-Process Interference in Large Language Models
Sourav Chattaraj and Kanak Raj
Large
language models can process millions of
tokens, yet how they handle conflicting information within context remains poorly understood. From patient health logs tracking evolving vital signs to legal documents with superseding clauses, real-world applications routinely require models to retrieve specific values from streams of semantically similar, competing updates. We adapt classical interference paradigms from cognitive psychology to compare retroactive interference (RI; recalling initial values after updates) and proactive interference (PI; recalling recent values despite competing prior encodings) across 39 LLMs spanning 1B to 2.5T parameters. Every model exhibits the same pattern: PI causes substantially greater degradation than RI (d = 1.73), the opposite of the typical human finding where new information more readily disrupts old. Four lines of evidence indicate that RI and PI engage distinct mechanisms: model size predicts RI resistance but not PI; the two scores correlate only weakly; error analysis reveals qualitatively different failure profiles, with RI failures reflecting passive
retrieval failure and PI failures reflecting active primacy intrusion; and
hallucination rates remain below 1% in both conditions. An adaptive bootstrap design further shows that RI decays smoothly while PI collapses bimodally at high interference, consistent with gradual dilution versus winner-take-all
attention dynamics. These findings characterize a systematic primacy bias in
transformer attention, with implications for reliable deployment in settings where in-context information evolves over time.
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Computation and Language · Cross-listed from cs.CR
Your Inference Request Will Become a Black Box: Confidential Inference for Cloud-based Large Language Models
Chung-ju Huang, Huiqiang Zhao, Yuanpeng He et al. (+5 more)
The increasing reliance on cloud-hosted Large
Language Models (LLMs) exposes sensitive client data, such as
prompts and responses, to potential
privacy breaches by service providers. Existing approaches fail to ensure
privacy, maintain model performance, and preserve computational efficiency simultaneously. To address this challenge, we propose Talaria, a confidential inference framework that partitions the LLM pipeline to protect client data without compromising the cloud's model intellectual property or inference quality. Talaria executes sensitive, weight-independent operations within a client-controlled Confidential Virtual Machine (CVM) while offloading weight-dependent computations to the cloud GPUs. The interaction between these environments is secured by our Reversible Masked Outsourcing (ReMO) protocol, which uses a hybrid masking technique to reversibly obscure intermediate data before outsourcing computations. Extensive evaluations show that Talaria can defend against state-of-the-art
token inference attacks, reducing
token reconstruction accuracy from over 97.5% to an average of 1.34%, all while being a lossless mechanism that guarantees output identical to the original model without significantly decreasing efficiency and scalability. To the best of our knowledge, this is the first work that ensures clients'
prompts and responses remain inaccessible to the cloud, while also preserving model
privacy, performance, and efficiency.
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All authors Chung-ju Huang, Huiqiang Zhao, Yuanpeng He, Lijian Li, Wenpin Jiao, Zhi Jin, Peixuan Chen, Leye Wang
Computation and Language · Cross-listed from cs.AI
DARE-bench: Evaluating Modeling and Instruction Fidelity of LLMs in Data Science
Fan Shu, Yite Wang, Ruofan Wu et al. (+4 more)
The fast-growing demands in using Large
Language Models (LLMs) to tackle complex multi-step data science tasks create an emergent need for accurate benchmarking. There are two major gaps in existing
benchmarks: (i) the lack of standardized, process-aware evaluation that captures instruction adherence and process fidelity, and (ii) the scarcity of accurately labeled training data. To bridge these gaps, we introduce DARE-bench, a
benchmark designed for machine learning modeling and data science instruction following. Unlike many existing
benchmarks that rely on human- or model-based judges, all tasks in DARE-bench have verifiable ground truth, ensuring objective and reproducible evaluation. To cover a broad range of tasks and support agentic tools, DARE-bench consists of 6,300 Kaggle-derived tasks and provides both large-scale training data and evaluation sets. Extensive evaluations show that even highly capable models such as gpt-o4-mini struggle to achieve good performance, especially in machine learning modeling tasks. Using DARE-bench training tasks for fine-tuning can substantially improve model performance. For example, supervised fine-tuning boosts Qwen3-32B's accuracy by 1.83x and reinforcement learning boosts Qwen3-4B's accuracy by more than 8x. These significant improvements verify the importance of DARE-bench both as an accurate evaluation
benchmark and critical training data.
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All authors Fan Shu, Yite Wang, Ruofan Wu, Boyi Liu, Zhewei Yao, Yuxiong He, Feng Yan
Computation and Language
Do LLMs Benefit From Their Own Words?
Jenny Y. Huang, Leshem Choshen, Wei Sun et al. (+5 more)
In multi-turn conversations, large
language models typically condition on the full conversation history: both past user
prompts and assistant responses. We revisit this design choice by comparing full-context prompting to four alternative, substantially-reduced context configurations. Analyzing in-the-wild multi-turn conversations across three open
reasoning and one state-of-the-art model, we find that response quality is largely preserved under aggressive context filtering: replacing all prior assistant turns with one-sentence summaries or keeping only the most recent user–assistant exchange often matches storing full context in performance while using roughly 8x less context. To understand this result, we observe that a substantial fraction of user turns (36.4%) in multi-turn conversations are self-contained and that many follow-up turns can be addressed by seeing only the immediately preceding user–assistant exchange. Furthermore, we find that when models condition on their own past responses, this can lead to context pollution, a phenomenon in which
reasoning errors,
hallucinations, or stylistic artifacts propagate across turns. Motivated by these findings, we design a context-filtering approach that selectively omits the assistant-side history. Taken together, these findings suggest moving away from storing full dialogue transcripts and instead retaining only what is relevant.
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All authors Jenny Y. Huang, Leshem Choshen, Wei Sun, Omar Khattab, Ramón Fernandez Astudillo, Mehul Damani, Tamara Broderick, Jacob Andreas
Computation and Language · Cross-listed from cs.LG
Taming Momentum: Rethinking Optimizer States Through Low-Rank Approximation
Zhengbo Wang, Jian Liang, Ran He et al. (+2 more)
Modern optimizers like Adam and
Muon are central to training large
language models, but their reliance on first- and second-order momenta introduces significant
memory overhead, which constrains scalability and computational efficiency. In this work, we reframe the exponential moving average (EMA) used in these momenta as the training of a linear regressor via online gradient flow. Building on this equivalence, we introduce LoRA-Pre, a novel low-rank optimizer designed for efficient pre-training. Specifically, LoRA-Pre reduces the optimizer's
memory footprint by decomposing the full momentum
matrix into a compact low-rank subspace within the online linear learner, thereby maintaining optimization performance while improving
memory efficiency. We empirically validate LoRA-Pre's efficacy by pre-training models from the Llama architecture family, scaling from 60M to 1B parameters. LoRA-Pre achieves the highest performance across all model sizes. Notably, LoRA-Pre demonstrates remarkable rank efficiency, achieving comparable or superior results using only 1/8 the rank of baseline methods. Beyond pre-training, we evaluate LoRA-Pre's effectiveness in fine-tuning scenarios. With the same rank, LoRA-Pre consistently outperforms all efficient fine-tuning baselines. Specifically, compared to standard LoRA, LoRA-Pre achieves substantial improvements of 3.14 points on Llama-3.1-8B and 6.17 points on Llama-2-7B, validating our approach's effectiveness across both pre-training and fine-tuning paradigms. Our code is publicly available at https://github.com/mrflogs/LoRA-Pre.
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All authors Zhengbo Wang, Jian Liang, Ran He, Zilei Wang, Tieniu Tan
Computation and Language
From Leaky Thoughts to Private Reasoning: Controlling What LRMs Say to Themselves
Haritz Puerto, Haonan Li, Xudong Han et al. (+2 more)
Large
reasoning models (LRMs) produce
reasoning traces (RTs) that often contain sensitive information. These leaky thoughts are difficult to control and frequently violate explicit
privacy directives. Because RTs can be exposed through
prompt injection attacks, this becomes a direct
privacy risk to the user. We approach this as a controllability problem: since
privacy directives are themselves instructions, improving instruction-following (IF) within the RT provides a direct path to reducing
privacy leaks. To this end, we introduce an SFT
dataset that teaches models to follow general instructions throughout their
reasoning process, and propose Staged Decoding, a simple decoding strategy that decouples RT and answer generation using separate LoRA adapters to maximize IF of each component. We evaluate our approach on six models from two families (1.7B-14B parameters), across two IF
benchmarks and two
privacy benchmarks. Our method yields substantial improvements, with gains of up to 20.9 points in IF and 51.9 percentage points on
privacy benchmarks, though these can come at the cost of task utility due to the trade-off between
reasoning performance and IF. Our results show that improving IF in LRMs can significantly enhance
privacy, suggesting a promising direction for future
privacy-aware LRMs. Our code is available at https://github.com/UKPLab/arxiv2026-controllable-
reasoning-models.
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All authors Haritz Puerto, Haonan Li, Xudong Han, Timothy Baldwin, Iryna Gurevych
Computation and Language · Cross-listed from cs.AI
Uncertainty Quantification for Multimodal Large Language Models with Incoherence-adjusted Semantic Volume
Gregory Kang Ruey Lau, Hieu Dao, Nicole Kan Hui Lin et al. (+1 more)
Despite their capabilities,
Multimodal Large
Language Models (MLLMs) may produce plausible but erroneous outputs, hindering reliable deployment. Accurate uncertainty metrics could enable escalation of unreliable queries to human experts or larger models for improved performance. However, existing uncertainty metrics have practical constraints, such as being designed only for specific modalities, reliant on external tools, or computationally expensive. We introduce UMPIRE, a training-free uncertainty quantification framework for MLLMs that works efficiently across various input and output modalities without external tools, relying only on the models' own internal modality features. UMPIRE computes the incoherence-adjusted semantic volume of sampled MLLM responses for a given task instance, effectively capturing both the global semantic diversity of samples and the local incoherence of responses based on internal model confidence. We propose uncertainty desiderata for MLLMs and provide theoretical analysis motivating UMPIRE's design. Extensive experiments show that UMPIRE consistently outperforms baseline metrics in error detection and uncertainty calibration across image, audio, and
video-text
benchmarks, including
adversarial and out-of-distribution settings. We also demonstrate UMPIRE's generalization to non-text output tasks, including image and audio generation.
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All authors Gregory Kang Ruey Lau, Hieu Dao, Nicole Kan Hui Lin, Bryan Kian Hsiang Low
Computation and Language
MT-PingEval: Evaluating Multi-Turn Collaboration with Private Information Games
Jacob Eisenstein, Fantine Huot, Adam Fisch et al. (+2 more)
We present a scalable and verifiable methodology for evaluating
language models in multi-turn interactions, using a suite of collaborative games that require effective communication about private information. This enables an interactive scaling analysis, in which a fixed
token budget is divided over a variable number of turns. We find that
language models often fail to use interactive collaboration to improve over the non-interactive baseline in which one
agent summarizes its information and the other
agent immediately acts, despite substantial headroom. This suggests that state-of-the-art models still suffer from significant weaknesses in planning and executing multi-turn collaborative conversations. We analyze the linguistic features of these dialogues, assessing the roles of sycophancy, information density, and discourse coherence. While there is no single linguistic explanation for the collaborative weaknesses of contemporary
language models, we note that humans achieve comparable task success at superior
token efficiency by producing more coherent dialogues. The proactive management of private information is a defining feature of real-world communication, and this work is designed to drive further progress on this capability.
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All authors Jacob Eisenstein, Fantine Huot, Adam Fisch, Jonathan Berant, Mirella Lapata
Computation and Language
Task-Centric Acceleration of Small-Language Models
Dor Tsur, Sharon Adar and Ran Levy
Small
language models (SLMs) have emerged as efficient alternatives to large
language models for task-specific applications. However, they are often employed in high-volume, low-latency settings, where efficiency is crucial. We propose TASC, Task-Adaptive Sequence Compression, a framework for SLM acceleration comprising two use-cases: When performing SLM fine-tuning, we propose TASC-ft, which iteratively enriches the tokenizer vocabulary with high-frequency output n-grams and then fine-tunes the model to utilize the expanded vocabulary. Next, we propose an inference-time method, termed TASC-spec. TASC-spec is a lightweight, training-free speculative decoding method that constructs an n-gram draft model from the task's output corpus, mixing task and context n-gram information.TASC-spec avoids any additional training, while bypassing draft-target vocabulary
alignment constraints. We demonstrate the effectiveness of both methods across multiple low output-variability generation tasks. Our methods show consistent improvements in inference efficiency while maintaining task performance.
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Computation and Language
ArgLLM-App: An Interactive System for Argumentative Reasoning with Large Language Models
Adam Dejl, Deniz Gorur and Francesca Toni
Argumentative LLMs (ArgLLMs) are an existing approach leveraging Large
Language Models (LLMs) and computational argumentation for decision-making, with the aim of making the resulting decisions faithfully explainable to and contestable by humans. Here we propose a web-based system implementing ArgLLM-empowered
agents for binary tasks. ArgLLM-App supports visualisation of the produced explanations and interaction with human users, allowing them to identify and contest any mistakes in the system's
reasoning. It is highly modular and enables drawing information from trusted external sources. ArgLLM-App is publicly available at https://argllm.app, with a
video demonstration at https://youtu.be/vzwlGOr0sPM.
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Computation and Language
CoME: Empowering Channel-of-Mobile-Experts with Informative Hybrid-Capabilities Reasoning
Yuxuan Liu, Weikai Xu, Kun Huang et al. (+9 more)
Mobile
Agents can autonomously execute user instructions, which requires hybrid-capabilities
reasoning, including screen summary, subtask planning, action decision and action function. However, existing
agents struggle to achieve both decoupled enhancement and balanced integration of these capabilities. To address these challenges, we propose Channel-of-Mobile-Experts (CoME), a novel
agent architecture consisting of four distinct experts, each aligned with a specific
reasoning stage, CoME activates the corresponding expert to generate output
tokens in each
reasoning stage via output-oriented activation. To empower CoME with hybrid-capabilities
reasoning, we introduce a progressive training strategy: Expert-FT enables decoupling and enhancement of different experts' capability; Router-FT aligns expert activation with the different
reasoning stage; CoT-FT facilitates seamless collaboration and balanced optimization across multiple capabilities. To mitigate error propagation in hybrid-capabilities
reasoning, we propose InfoGain-Driven DPO (Info-DPO), which uses information gain to evaluate the contribution of each intermediate step, thereby guiding CoME toward more informative
reasoning. Comprehensive experiments show that CoME outperforms dense mobile
agents and MoE methods on both AITZ and AMEX
datasets.
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All authors Yuxuan Liu, Weikai Xu, Kun Huang, Changyu Chen, Jiankun Zhao, Pengzhi Gao, Wei Liu, Jian Luan, Shuo Shang, Bo Du, Ji-Rong Wen, Rui Yan
Computation and Language · Cross-listed from cs.CV
AgenticOCR: Parsing Only What You Need for Efficient Retrieval-Augmented Generation
Zhengren Wang, Dongsheng Ma, Huaping Zhong et al. (+4 more)
The expansion of
retrieval-augmented generation (RAG) into
multimodal domains has intensified the challenge for processing complex visual documents, such as financial reports. While page-level chunking and
retrieval is a natural starting point, it creates a critical bottleneck: delivering entire pages to the generator introduces excessive extraneous context. This not only overloads the generator's
attention mechanism but also dilutes the most salient evidence. Moreover, compressing these information-rich pages into a limited visual
token budget further increases the risk of
hallucinations. To address this, we introduce AgenticOCR, a dynamic parsing paradigm that transforms optical character recognition (OCR) from a static, full-text process into a query-driven, on-demand extraction system. By autonomously analyzing document layout in a "thinking with images" manner, AgenticOCR identifies and selectively recognizes regions of interest. This approach performs on-demand decompression of visual
tokens precisely where needed, effectively decoupling
retrieval granularity from rigid page-level chunking. AgenticOCR has the potential to serve as the "third building block" of the visual document RAG stack, operating alongside and enhancing standard
Embedding and Reranking modules. Experimental results demonstrate that AgenticOCR improves both the efficiency and accuracy of visual RAG systems, achieving expert-level performance in long document understanding. Code and models are available at https://github.com/OpenDataLab/AgenticOCR.
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All authors Zhengren Wang, Dongsheng Ma, Huaping Zhong, Jiayu Li, Wentao Zhang, Bin Wang, Conghui He
Computation and Language
Evaluating LLM-Based Translation of a Low-Resource Technical Language: The Medical and Philosophical Greek of Galen
James L. Zainaldin, Cameron Pattison, Manuela Marai et al. (+2 more)
Purpose: This study evaluates the quality of commercial large
language model (LLM) machine translation (MT) for Ancient Greek technical prose and
benchmarks standard automated MT evaluation metrics against expert human judgment. Design: We evaluated 60 translations by three LLMs (ChatGPT, Claude, Gemini) of 20 paragraph-length passages from 2 works by the Greek physician Galen (c. 129-216 CE): an expository text with two published English translations and a pharmacological text never before translated. Quality was assessed using seven automated metrics and systematic reference-free human evaluation via a modified Multidimensional Quality Metrics (MQM) framework applied by domain specialists. Findings: On the translated expository text, LLMs achieved high quality (mean MQM score 95.2/100). On the untranslated pharmacological text, quality was lower (79.9/100) but bimodally distributed: two passages with extreme terminological density produced catastrophic failures, while remaining passages scored within 4 points of the expository text. Terminology rarity, operationalized via corpus frequency, emerged as the dominant predictor of failure (r = -.97). Automated metrics showed moderate correlation with human judgment only on texts with wide quality variance; no metric discriminated among high-quality translations. Originality: This is the first systematic, reference-free expert human evaluation of LLM translation for any ancient
language and the first study identifying textual properties predictive of translation failure.
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All authors James L. Zainaldin, Cameron Pattison, Manuela Marai, Jacob Wu, Mark J. Schiefsky
Computation and Language · Cross-listed from cs.CV
Toward Guarantees for Clinical Reasoning in Vision Language Models via Formal Verification
Vikash Singh, Debargha Ganguly, Haotian Yu et al. (+5 more)
Vision-
language models (VLMs) show promise in drafting radiology reports, yet they frequently suffer from logical inconsistencies, generating diagnostic impressions unsupported by their own perceptual findings or missing logically entailed conclusions. Standard lexical metrics heavily penalize clinical paraphrasing and fail to capture these deductive failures in reference-free settings. Toward guarantees for clinical
reasoning, we introduce a neurosymbolic verification framework that deterministically audits the internal consistency of VLM-generated reports. Our pipeline autoformalizes free-text radiographic findings into structured propositional evidence, utilizing an SMT solver (Z3) and a clinical knowledge base to verify whether each diagnostic claim is mathematically entailed, hallucinated, or omitted. Evaluating seven VLMs across five chest X-ray
benchmarks, our verifier exposes distinct
reasoning failure modes, such as conservative observation and
stochastic hallucination, that remain invisible to traditional metrics. On labeled
datasets, enforcing solver-backed entailment acts as a rigorous post-hoc guarantee, systematically eliminating unsupported
hallucinations to significantly increase diagnostic soundness and precision in generative clinical assistants.
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All authors Vikash Singh, Debargha Ganguly, Haotian Yu, Chengwei Zhou, Prerna Singh, Brandon Lee, Vipin Chaudhary, Gourav Datta
Computation and Language · Cross-listed from cs.AI
Recycling Failures: Salvaging Exploration in RLVR via Fine-Grained Off-Policy Guidance
Yanwei Ren, Haotian Zhang, Likang Xiao et al. (+6 more)
Reinforcement Learning from Verifiable Rewards (RLVR) has emerged as a powerful paradigm for enhancing the complex
reasoning capabilities of Large
Reasoning Models. However, standard outcome-based supervision suffers from a critical limitation that penalizes trajectories that are largely correct but fail due to several missteps as heavily as completely erroneous ones. This coarse feedback signal causes the model to discard valuable largely correct rollouts, leading to a degradation in rollout diversity that prematurely narrows the exploration space. Process Reward Models have demonstrated efficacy in providing reliable step-wise verification for test-time scaling, naively integrating these signals into RLVR as dense rewards proves ineffective.Prior methods attempt to introduce off-policy guided whole-trajectory replacement that often outside the policy model's distribution, but still fail to utilize the largely correct rollouts generated by the model itself and thus do not effectively mitigate the narrowing of the exploration space. To address these issues, we propose SCOPE (Step-wise Correction for On-Policy Exploration), a novel framework that utilizes Process Reward Models to pinpoint the first erroneous step in suboptimal rollouts and applies fine-grained, step-wise off-policy rectification. By applying precise refinement on partially correct rollout, our method effectively salvages partially correct trajectories and increases diversity score by 13.5%, thereby sustaining a broad exploration space. Extensive experiments demonstrate that our approach establishes new state-of-the-art results, achieving an average accuracy of 46.6% on math
reasoning and exhibiting robust generalization with 53.4% accuracy on out-of-distribution
reasoning tasks.
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All authors Yanwei Ren, Haotian Zhang, Likang Xiao, Xikai Zhang, Jiaxing Huang, Jiayan Qiu, Baosheng Yu, Quan Chen, Liu Liu
Computation and Language
ARGUS: Seeing the Influence of Narrative Features on Persuasion in Argumentative Texts
Sara Nabhani, Federico Pianzola, Khalid Al-Khatib et al. (+1 more)
Can narratives make arguments more persuasive? And to this end, which narrative features matter most? Although stories are often seen as powerful tools for persuasion, their specific role in online, unstructured argumentation remains underexplored. To address this gap, we present ARGUS, a framework for studying the impact of narration on persuasion in argumentative discourse. ARGUS introduces a new ChangeMyView corpus annotated for story presence and six key narrative features, integrating insights from two established theoretical frameworks that capture both textual narrative features and their effects on recipients. Leveraging both encoder-based classifiers and zero-shot large
language models (LLMs), ARGUS identifies stories and narrative features and applies them at scale to examine how different narrative dimensions influence persuasion success in online argumentation.
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All authors Sara Nabhani, Federico Pianzola, Khalid Al-Khatib, Malvina Nissim
Computation and Language
Preference Packing: Efficient Preference Optimization for Large Language Models
Jaekyung Cho
Resource-efficient training optimization techniques are becoming increasingly important as the size of large
language models (LLMs) continues to grow. In particular, batch packing is commonly used in pre-training and supervised fine-tuning to achieve resource-efficient training. We propose preference packing, a method to enhance resource efficiency in training techniques that use data with different responses for the same input
prompt, such as reward models or Direct Preference Optimization (DPO). Preference packing improves resource efficiency by reducing the
attention operations for duplicate input
prompts and decreasing KV cache
memory usage. We conducted experiments on text-only
datasets and image-included
datasets and achieved at least 37% reduction in training time. Notably, this method can be applied alongside existing optimization techniques such as batch sorting, resulting in a 3.22x speedup.
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Computation and Language · Cross-listed from cs.SD
SongSong: A Time Phonograph for Chinese SongCi Music from Thousand of Years Away
Jiajia Li, Jiliang Hu, Ziyi Pan et al. (+4 more)
Recently, there have been significant advancements in music generation. However, existing models primarily focus on creating modern pop songs, making it challenging to produce ancient music with distinct rhythms and styles, such as ancient Chinese SongCi. In this paper, we introduce SongSong, the first music generation model capable of restoring Chinese SongCi to our knowledge. Our model first predicts the melody from the input SongCi, then separately generates the singing voice and accompaniment based on that melody, and finally combines all elements to create the final piece of music. Additionally, to address the lack of ancient music
datasets, we create OpenSongSong, a comprehensive
dataset of ancient Chinese SongCi music, featuring 29.9 hours of compositions by various renowned SongCi music masters. To assess SongSong's proficiency in performing SongCi, we randomly select 85 SongCi sentences that were not part of the training set for evaluation against SongSong and music generation platforms such as Suno and SkyMusic. The subjective and objective outcomes indicate that our proposed model achieves leading performance in generating high-quality SongCi music.
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All authors Jiajia Li, Jiliang Hu, Ziyi Pan, Chong Chen, Zuchao Li, Ping Wang, Lefei Zhang