Large Language Model
SuperActivators: Only the Tail of the Distribution Contains Reliable Concept Signals
Goldberg, Cassandra, Kim, Chaehyeon, Stein, Adam, Wong, Eric
Concept vectors aim to enhance model interpretability by linking internal representations with human-understandable semantics, but their utility is often limited by noisy and inconsistent activations. In this work, we uncover a clear pattern within the noise, which we term the SuperActivator Mechanism: while in-concept and out-of-concept activations overlap considerably, the token activations in the extreme high tail of the in-concept distribution provide a reliable signal of concept presence. We demonstrate the generality of this mechanism by showing that SuperActivator tokens consistently outperform standard vector-based and prompting concept detection approaches, achieving up to a 14% higher F1 score across image and text modalities, model architectures, model layers, and concept extraction techniques. Finally, we leverage SuperActivator tokens to improve feature attributions for concepts.
Factuality and Transparency Are All RAG Needs! Self-Explaining Contrastive Evidence Re-ranking
Vargas, Francielle, Pedronette, Daniel
This extended abstract introduces Self-Explaining Contrastive Evidence Re-Ranking (CER), a novel method that restructures retrieval around factual evidence by fine-tuning embeddings with contrastive learning and generating token-level attribution rationales for each retrieved passage. Hard negatives are automatically selected using a subjectivity-based criterion, forcing the model to pull factual rationales closer while pushing subjective or misleading explanations apart. As a result, the method creates an embedding space explicitly aligned with evidential reasoning. We evaluated our method on clinical trial reports, and initial experimental results show that CER improves retrieval accuracy, mitigates the potential for hallucinations in RAG systems, and provides transparent, evidence-based retrieval that enhances reliability, especially in safety-critical domains.
Reflection Removal through Efficient Adaptation of Diffusion Transformers
Zakarin, Daniyar, Wandel, Thiemo, Obukhov, Anton, Dai, Dengxin
We introduce a diffusion-transformer (DiT) framework for single-image reflection removal that leverages the generalization strengths of foundation diffusion models in the restoration setting. Rather than relying on task-specific architectures, we repurpose a pre-trained DiT-based foundation model by conditioning it on reflection-contaminated inputs and guiding it toward clean transmission layers. We systematically analyze existing reflection removal data sources for diversity, scalability, and photorealism. To address the shortage of suitable data, we construct a physically based rendering (PBR) pipeline in Blender, built around the Principled BSDF, to synthesize realistic glass materials and reflection effects. Efficient LoRA-based adaptation of the foundation model, combined with the proposed synthetic data, achieves state-of-the-art performance on in-domain and zero-shot benchmarks. These results demonstrate that pretrained diffusion transformers, when paired with physically grounded data synthesis and efficient adaptation, offer a scalable and high-fidelity solution for reflection removal. Project page: https://hf.co/spaces/huawei-bayerlab/windowseat-reflection-removal-web
Strategic Self-Improvement for Competitive Agents in AI Labour Markets
Chiu, Christopher, Zhang, Simpson, van der Schaar, Mihaela
As artificial intelligence (AI) agents are deployed across economic domains, understanding their strategic behavior and market-level impact becomes critical. This paper puts forward a groundbreaking new framework that is the first to capture the real-world economic forces that shape agentic labor markets: adverse selection, moral hazard, and reputation dynamics. Our framework encapsulates three core capabilities that successful LLM-agents will need: \textbf{metacognition} (accurate self-assessment of skills), \textbf{competitive awareness} (modeling rivals and market dynamics), and \textbf{long-horizon strategic planning}. We illustrate our framework through a tractable simulated gig economy where agentic Large Language Models (LLMs) compete for jobs, develop skills, and adapt their strategies under competitive pressure. Our simulations illustrate how LLM agents explicitly prompted with reasoning capabilities learn to strategically self-improve and demonstrate superior adaptability to changing market conditions. At the market level, our simulations reproduce classic macroeconomic phenomena found in human labor markets, while controlled experiments reveal potential AI-driven economic trends, such as rapid monopolization and systemic price deflation. This work provides a foundation to further explore the economic properties of AI-driven labour markets, and a conceptual framework to study the strategic reasoning capabilities in agents competing in the emerging economy.
Nex-N1: Agentic Models Trained via a Unified Ecosystem for Large-Scale Environment Construction
AGI Team, null, Cai, Yuxuan, Chen, Lu, Chen, Qiaoling, Ding, Yuyang, Fan, Liwen, Fu, Wenjie, Gao, Yufei, Guo, Honglin, Guo, Pinxue, Han, Zhenhua, He, Zhengfu, Hu, Hanglei, Hu, Kai, Hua, Shengjia, Huai, Tianyu, Huang, Baodai, Ji, Li, Jiang, Zhen, Lei, Zhikai, Li, Bufan, Lin, Jiahang, Lin, Lizhi, Liu, Jinxiu, Liu, Shichun, Liu, Ziming, Ni, Yuchen, Qian, Pengfang, Shen, Yujiong, Shi, Qingyun, Shu, Wentao, Sun, Peng, Suo, Yiran, Tang, Tian, Tian, Boyu, Wang, Guoteng, Wang, Junzhe, Wang, Peixin, Xi, Zhiheng, Yan, Hang, Yang, Jie, Yang, Zhixiong, Yao, Tianchu, Ye, Guangze, Yu, Qianxi, Zhang, Shuo, Zhang, Xinyue, Zhang, Yiqi, Zhao, Jiarong, Zheng, Miao, Zheng, Rui, Zhou, Enyu, Zhou, Jiazheng, Zhou, Maosen, Zhou, Yuhao, Gui, Tao, Zheng, Yining, Chen, Xinchi, Zhou, Jie, Feng, Siyuan, Chen, Qin, He, Liang, Zhang, Qi, Huang, Xuanjing, Qiu, Xipeng
The evolution of Large Language Models (LLMs) from passive responders to autonomous agents necessitates a fundamental shift in learning paradigms -- from static imitation to incentive-driven decision making. However, this transition is significantly impeded by the lack of scalable infrastructure capable of constructing high-quality interaction signals for effective policy learning. To address this, we introduce a comprehensive method designed to systematically scale the diversity and complexity of interactive environments. Our method realizes this scaling by addressing three orthogonal dimensions: (1) Complexity: NexAU, a flexible agent framework that supports building complex agent hierarchies via simple configurations; (2) Diversity: NexA4A automatically generates diverse agent hierarchies from natural language to cover infinite domains; and (3) Fidelity: NexGAP bridges the simulation-reality gap by integrating dynamic real-world environment for grounded trajectories synthesis. We train Nex-N1 upon the diverse and complex interactive environments established by our infrastructure. Empirical results on benchmarks such as SWE-bench and tau2 demonstrate that Nex-N1 consistently outperforms SOTA open-source models and achieves competitive performance against frontier proprietary models on complex agentic tasks. We open-source the Nex ecosystem and model weights to facilitate further research.
GeoPE:A Unified Geometric Positional Embedding for Structured Tensors
Standard Vision Transformers flatten 2D images into 1D sequences, disrupting the natural spatial topology. While Rotary Positional Embedding (RoPE) excels in 1D, it inherits this limitation, often treating spatially distant patches (e.g., at row edges) as sequence neighbors. Existing 2D approaches typically treat spatial axes independently, failing to decouple this false sequential proximity from true spatial distance. To restore the 2D spatial manifold, we introduce Geometric Positional Embedding (GeoPE), a framework that extends rotations to 3D Euclidean space using quaternions. To overcome non-commutativity and ensure symmetry, GeoPE constructs a unified rotational operator by computing the geometric mean in the Lie algebra. This creates a geometrically coupled encoding that effectively separates spatial dimensions. Extensive experiments on image classification, object detection, and 3D semantic segmentation demonstrate that GeoPE consistently outperforms existing 2D RoPE variants and significantly enhances shape bias, confirming its ability to capture true geometric structure.
LLMs Know More Than Words: A Genre Study with Syntax, Metaphor & Phonetics
Shi, Weiye, Zhang, Zhaowei, Yan, Shaoheng, Yang, Yaodong
Large language models (LLMs) demonstrate remarkable potential across diverse language-related tasks, yet whether they capture deeper linguistic properties--such as syntactic structure, phonetic cues, and metrical patterns--from raw text remains unclear. To analysis whether LLMs can learn these features effectively and apply them to important nature language related tasks, we introduce a novel multilingual genre classification dataset derived from Project Gutenberg, a large-scale digital library offering free access to thousands of public domain literary works, comprising thousands of sentences per binary task (poetry vs. novel; drama vs. poetry; drama vs. novel) in six languages (English, French, German, Italian, Spanish, and Portuguese). We augment each with three explicit linguistic feature sets (syntactic tree structures, metaphor counts, and phonetic metrics) to evaluate their impact on classification performance. Experiments demonstrate that although LLM classifiers can learn latent linguistic structures either from raw text or from explicitly provided features, different features contribute unevenly across tasks, which underscores the importance of incorporating more complex linguistic signals during model training.
CARL: Critical Action Focused Reinforcement Learning for Multi-Step Agent
Shen, Leyang, Zhang, Yang, Ling, Chun Kai, Zhao, Xiaoyan, Chua, Tat-Seng
Agents capable of accomplishing complex tasks through multiple interactions with the environment have emerged as a popular research direction. However, in such multi-step settings, the conventional group-level policy optimization algorithm becomes suboptimal because of its underlying assumption that each action holds equal contribution, which deviates significantly from reality. Our analysis reveals that only a small fraction of actions are critical in determining the final outcome. Building on this insight, we propose CARL, a critical-action-focused reinforcement learning algorithm tailored for multi-step agents. CARL achieves focused training through providing action-level optimization signals for high-criticality actions while excluding low-criticality actions from model update. Extensive experiments demonstrate that CARL achieves both stronger performance and higher efficiency during training and inference across diverse evaluation settings.
Algorithmic Thinking Theory
Bateni, MohammadHossein, Cohen-Addad, Vincent, Gu, Yuzhou, Lattanzi, Silvio, Meierhans, Simon, Mohri, Christopher
Initial challenges, such as grade-school mathematics (GSM8K) and standard competition math (MATH dataset), have largely been surmounted, pushing the frontier of AI reasoning toward "grand challenge" problems, such as those found in the International Mathematical Olympiad (IMO). These problems, renowned for their demand for deep insight, creativity, and rigorous proof, expose a fascinating weakness in modern LLMs. While a model's performance on a single attempt (termed pass@1) may be very low, its ability to produce a correct answer within k attempts (pass@k) can be significantly higher. This pass@1 versus pass@k gap, especially pronounced when sampling with high temperature to produce diverse outputs, suggests that models possess a vast, latent capability that is not accessible in a single, high-confidence generation. Interestingly, to recover the full power of the model it is not sufficient to simply use multiple attempts. In fact, even the pass@k metric fails to capture the full story. On the most difficult problems, simply sampling k times and selecting the best answer (e.g., "best-of-32") still yields poor results. For instance, Huang and Yang (2025) report that a best-of-32 baseline on the IMO 2025 problems achieved an accuracy of only 31.6-38.1% for leading models [HY25]. This paradox lies at the heart of our work: the latent capability of LLMs is not merely a matter of selection (finding one correct needle in a haystack of k attempts), but one of synthesis.
STELLA: Guiding Large Language Models for Time Series Forecasting with Semantic Abstractions
Fan, Junjie, Zhao, Hongye, Wei, Linduo, Rao, Jiayu, Li, Guijia, Yuan, Jiaxin, Xu, Wenqi, Qi, Yong
Recent adaptations of Large Language Models (LLMs) for time series forecasting often fail to effectively enhance information for raw series, leaving LLM reasoning capabilities underutilized. Existing prompting strategies rely on static correlations rather than generative interpretations of dynamic behavior, lacking critical global and instance-specific context. To address this, we propose STELLA (Semantic-Temporal Alignment with Language Abstractions), a framework that systematically mines and injects structured supplementary and complementary information. STELLA employs a dynamic semantic abstraction mechanism that decouples input series into trend, seasonality, and residual components. It then translates intrinsic behavioral features of these components into Hierarchical Semantic Anchors: a Corpus-level Semantic Prior (CSP) for global context and a Fine-grained Behavioral Prompt (FBP) for instance-level patterns. Using these anchors as prefix-prompts, STELLA guides the LLM to model intrinsic dynamics. Experiments on eight benchmark datasets demonstrate that STELLA outperforms state-of-the-art methods in long- and short-term forecasting, showing superior generalization in zero-shot and few-shot settings. Ablation studies further validate the effectiveness of our dynamically generated semantic anchors.