Machine learning

Fri, Oct 309 papers

arXiv

Training Foundation Models with a Single Algorithm

Yuda Song, Alvin Zhang, Fahim Tajwar et al.

Foundation models are typically trained in stages: pretraining, midtraining, supervised fine-tuning (SFT), and reinforcement learning (RL), with changes in both data and…Foundation models are typically trained in stages: pretraining, midtraining, supervised fine-tuning (SFT), and reinforcement learning (RL), with changes in both data and learning algorithms.

Accuracy and coverage across training compute budgets.
Preprint: method
arXiv

Closing the Log Gap: Minimax-Optimal Regret for Episodic RL

Guy Zamir, Victor Boone, Matthew Zurek et al.

In this paper, we study the regret minimization problem in episodic tabular MDPs. Our algorithm achieves the first expected regret bound scaling as √H³ S A K for…In this paper, we study the regret minimization problem in episodic tabular MDPs. Our algorithm achieves the first expected regret bound scaling as √H³ S A K for sufficiently large K, where H is the episode length, K is the number…

Preprint: method
arXiv

DWISE: Denoising Workload-Informed Scheduling Engine

Lie Li, Wen Li, Junxiao Shen et al.

Unlike autoregressive large language models (AR-LLMs), diffusion LLMs (dLLMs) generate text by iteratively denoising many tokens in parallel, offering a promising path to…Unlike autoregressive large language models (AR-LLMs), diffusion LLMs (dLLMs) generate text by iteratively denoising many tokens in parallel, offering a promising path to efficient inference.

Preprint: system
arXiv

There Is No Free Lunch in RLVR: Every pass@1 Gain Has a pass@k Price

Yinuo Liu

Reinforcement learning with verifiable rewards (RLVR) makes a language model solve more problems on the first try and fewer when given many tries: it raises pass@1 while…Reinforcement learning with verifiable rewards (RLVR) makes a language model solve more problems on the first try and fewer when given many tries: it raises pass@1 while the base model overtakes it at large sampling budget k.

Per-prompt loss is inevitable under specialization, but the aggregate pass@ k crossover is conditional on Assumption 2.
Preprint: theory
arXiv

ParaTTT: Parallelizing Test-Time Training Layers with Deep Memories

Noel Loo, Neehal Tumma, T. Konstantin Rusch et al.

Test-time training (TTT) layers replace the linear fast-weight memory of modern recurrent architectures with a small neural network trained online by gradient descent.Test-time training (TTT) layers replace the linear fast-weight memory of modern recurrent architectures with a small neural network trained online by gradient descent.

Preprint: method
arXiv

Nearly Minimax Optimal Regret for Adversarial Linear Bandits with Strong Corruptions

Qiwei Di, Quanquan Gu

We study adversarial linear bandits with strong corruption, in which an adaptive adversary chooses the reward vectors and a strong adversary corrupts each observed reward…We study adversarial linear bandits with strong corruption, in which an adaptive adversary chooses the reward vectors and a strong adversary corrupts each observed reward after seeing the learner's action, subject to a known total…

Preprint: method
arXiv

Local search can match global methods on a noisy signal task

A proof showed that random search with cooling and averaging could recover a hidden vector above the same signal threshold as established global methods.A proof showed that random search with cooling and averaging could recover a hidden vector above the same signal threshold as established global methods.

A sphere holds a winding black path around a dark blue-green spindle, with a matching spindle outside and scattered gray and blue-green pieces nearby.
Preprint: theory
arXiv

Jailbreak Connectivity: Towards Diverse, Transferable, and Universal Multimodal Large Language Model Jailbreak

Xu Zhang, Ziqing Hu, Shuo Han et al.

Multimodal large language models (MLLMs) are vulnerable to visual jailbreak attacks that bypass safety safeguards.Multimodal large language models (MLLMs) are vulnerable to visual jailbreak attacks that bypass safety safeguards. Existing methods typically optimize isolated adversarial examples, limiting attack diversity, transferability, and…

Preprint: method
arXiv

What a Weight Update Buys: Leverage Across Training Stages

Shikhar Shiromani

Post-training moves a language model's weights by about a thousandth of their norm and changes its behavior sharply; pretraining moves them by a third and buys a slow…Post-training moves a language model's weights by about a thousandth of their norm and changes its behavior sharply; pretraining moves them by a third and buys a slow drift.

Preprint: method

Wed, Oct 2814 papers

arXiv

Heads of Security: Learned Attention Gates Improve Prompt Injection Robustness

Igor Shilov, Xiaoxue Yang, Alexander Panfilov et al.

We introduce Heads of Security (HoS), a prompt injection defense that enforces instruction-data separation via a small set of learned per-head attention gates.We introduce Heads of Security (HoS), a prompt injection defense that enforces instruction-data separation via a small set of learned per-head attention gates.

Learned attention gates for Llama-3.3-70B.
Preprint: method
arXiv

Gym-Anything-RT: Scaling Real-Time Environments for Vision-Language Agents

Pranjal Aggarwal, Sean Welleck

AI agents have made substantial progress in domains where they have a non-trivial amount of time to deliberate between actions, such as mathematics, software engineering…AI agents have made substantial progress in domains where they have a non-trivial amount of time to deliberate between actions, such as mathematics, software engineering, and performing tasks on desktop applications.

Preprint: benchmark or dataset
arXiv

Collective Dynamics of Self-Reinforcement: How Cross-Task Coupling Drives Policy Collapse in Unsupervised RLVR

Peize Ding

Label-free reinforcement learning with verifiable rewards (RLVR) rewards a language model for agreeing with its own majority vote.Label-free reinforcement learning with verifiable rewards (RLVR) rewards a language model for agreeing with its own majority vote. It improves reasoning at first but eventually collapses: the self-assessed reward goes to one while…

Preprint: theory
arXiv

GTFormer: A Syntax-Free Graph Network Alternative to Transformers for 8192× Length Extrapolation in Linear Time

Elisabeth Fink

Self-attention mechanisms have established the Transformer as the dominant backbone across natural language processing, source code intelligence, and automated theorem…Self-attention mechanisms have established the Transformer as the dominant backbone across natural language processing, source code intelligence, and automated theorem proving.

Preprint: new model
arXiv

Follow the Gradient: Tracing Safety Degradation Back to Training Data

Saket Reddy, Amro Abbas, Anshuman Suri et al.

Fine-tuning Large Language Models (LLMs) on instruction data can quietly erode their safety, even when no training example looks harmful.Fine-tuning Large Language Models (LLMs) on instruction data can quietly erode their safety, even when no training example looks harmful. Because this safety-degrading data looks benign, standard content filters struggle to catch…

Detection AUC against embedding wall-clock time for each optimization strategy.
Preprint: method
arXiv

LinMix: Data Mixing as Linear Domain Attribution

Hubert Baniecki, Przemyslaw Biecek, Martin Pawelczyk

Language model performance depends strongly on the mixture of domains in the pretraining data corpus. Popular data mixing methods select these domain weights by training…Language model performance depends strongly on the mixture of domains in the pretraining data corpus. Popular data mixing methods select these domain weights by training many small proxy models on random mixes and then fitting a…

Dirichlet sampling with default γ,τ hyperparameters does not converge for 288 domains.
Preprint: method
arXiv

Channel Selection for Mixture-of-Experts Decoding Needs No Calibration Data

Geunhyoung Kim, Sung Ju Hwang

Mixture-of-Experts (MoE) models are bottlenecked by loading routed-expert weights from memory during interactive decoding at small batch sizes.Mixture-of-Experts (MoE) models are bottlenecked by loading routed-expert weights from memory during interactive decoding at small batch sizes.

Preprint: method
arXiv

EmbeddingGemma 2: Unified and Efficient Multimodal Representations

Henrique Schechter Vera, Sahil Dua, Jovan Andonov et al.

We present EmbeddingGemma 2, an open multimodal embedding model which natively represents text, images, audio, video, and combinations thereof in a unified space.We present EmbeddingGemma 2, an open multimodal embedding model which natively represents text, images, audio, video, and combinations thereof in a unified space.

EmbeddingGemma 2 natively maps text, images, video, audio, and combinations thereof into a unified, semantically-aligned vector space.
Preprint: new model
arXiv

When Is a Relation Worth Trusting? Manipulation Costs, Exposure, and the Trust Trap in Multi-Relational Graph Learning

Vincess Dongmo, Astride Melvin Fokam Ninyim

Multi-relational graph detectors learn from clean data how much to trust each relation, but an adversary pays a different price to manipulate each relation and each…Multi-relational graph detectors learn from clean data how much to trust each relation, but an adversary pays a different price to manipulate each relation and each action; taking such costs as given, we ask when using a relation…

Preprint: theory
arXiv

Exploring the Limits of the Delta Learning Hypothesis: Single-Pair Generator Biases in Direct Preference Optimization

Giuseppe Curci, Stefano Simonazzi, Andrea Molinari et al.

Direct Preference Optimization (DPO) typically relies on preference pairs generated from diverse model pools and ranked by an external LLM judge.Direct Preference Optimization (DPO) typically relies on preference pairs generated from diverse model pools and ranked by an external LLM judge.

Preprint: empirical study
arXiv

Confidence Is Not a Promise: A Reference Audit of Typed Decision Models

Pedro Carvalho Brom

Typed decision models return a probability distribution over options supplied by the caller, and software tends to act on that number as if it were a guarantee.Typed decision models return a probability distribution over options supplied by the caller, and software tends to act on that number as if it were a guarantee.

Preprint: empirical study
arXiv

h1: A Taste of the Bitter Lesson in Automated Theorem Proving

Skander Moalla, Ahmad Rammal, Niket Patel et al.

While progress in informal mathematics has come largely from scaling the chain-of-thought and agentic reasoning of frontier language models, formal theorem proving has…While progress in informal mathematics has come largely from scaling the chain-of-thought and agentic reasoning of frontier language models, formal theorem proving has increasingly relied on human-designed workflows around these…

Preprint: system
arXiv

SEEK: Skill Extraction with Evolving Knowledge against Frontier Science Agents

Cheng Gui, Xiang Zheng, Yutao Wu et al.

Science agents increasingly package domain expertise as reusable skills that plan analyses, select tools, and execute workflows.Science agents increasingly package domain expertise as reusable skills that plan analyses, select tools, and execute workflows. This modularity creates a confidentiality risk: the interactions that deliver a skill's capability…

图 1. Overall framework of SEEK.
Preprint: new model

Tue, Oct 274 papers

arXiv

BellowsKV: One Latent for Many Layers, Expanded on Demand

Jiamu Zhang, Hanjie Chen

Large language models (LLMs) now serve as the backbone of agents that reason over many turns, call tools, and pursue long-horizon tasks.Large language models (LLMs) now serve as the backbone of agents that reason over many turns, call tools, and pursue long-horizon tasks. To avoid recomputation, a model stores the attention keys and values of all past tokens in a…

Preprint: method

Mon, Oct 266 papers

arXiv

Near-Optimal List Replicability from Littlestone Dimension

Ari Blondal, Pooya Hatami, Chavdar Lalov et al.

We study the list replicability number in the realizable PAC learning framework and prove that every concept class H over a countable domain with Littlestone dimension d…We study the list replicability number in the realizable PAC learning framework and prove that every concept class H over a countable domain with Littlestone dimension d and dual VC dimension v^(*) satisfies [ LR(H)≤ 2^{O(dmin{log…

Preprint: theory
arXiv

Optimal Multiclass Online Regret with Arbitrary Label Spaces

Sajad Ashkezari, Shai Ben-David

We determine the optimal regret in agnostic multiclass online learning with arbitrary, possibly infinite, label spaces.We determine the optimal regret in agnostic multiclass online learning with arbitrary, possibly infinite, label spaces. For every hypothesis class of multiclass Littlestone dimension d<∞, we prove a regret upper bound of…

Preprint: theory
arXiv

Putting Transformer Theories to the Test

Awni Altabaa, Tobias Schnabel, Kiran Tomlinson

Several formal theories have been developed to characterize the capabilities and limitations of the transformer architecture, each employing different abstractions that…Several formal theories have been developed to characterize the capabilities and limitations of the transformer architecture, each employing different abstractions that capture different features of the architecture.

Preprint: empirical study
arXiv

Sharp Bounds on the Winner's Bias under Independent and Nonnegatively Correlated Noise

Ivan Viakhirev, Kirill Borodin, Grach Mkrtchian

Reporting the best of M noisy, unbiased scores overstates the winner's value by up to c√V, where V is the total noise variance and the sharp constant c depends on how the…Reporting the best of M noisy, unbiased scores overstates the winner's value by up to c√V, where V is the total noise variance and the sharp constant c depends on how the noise is dependent.

Preprint: theory
arXiv

Forecasting Associations, Not Interventions: A Preregistered Causal Audit of Covariate-Aware Time Series Foundation Models

Zong-Han Bai

Covariate-aware time series foundation models (TSFMs) accept a future path for a control variable and return a forecast, inviting what-if queries.Covariate-aware time series foundation models (TSFMs) accept a future path for a control variable and return a forecast, inviting what-if queries. The query is interventional; the models are trained on observational data.

Preprint: empirical study
arXiv

Rewriting Scaling Laws for Synthetic Data with Compute and Data Constraints

Nicholas Roberts, Ahmed Ahmed, Suhas Kotha et al.

Synthetic rewrites, where a language model rewrites a natural document e.g. into a target style, are now a standard ingredient of pretraining corpora.Synthetic rewrites, where a language model rewrites a natural document e.g. into a target style, are now a standard ingredient of pretraining corpora.

Preprint: empirical study

Fri, Oct 23

arXiv

Efficient and Optimal Learning of Discrete Distributions with Person-Level Privacy

Gautam Kamath, Mahbod Majid, Ankur Moitra et al.

We study learning a discrete distribution under person-level differential privacy in the batched setting. Given n users, each contributing m i.i.d.We study learning a discrete distribution under person-level differential privacy in the batched setting. Given n users, each contributing m i.i.d.

Preprint: theory
arXiv

On the Token Collapse Phenomenon in Textual Graph Soft Prompting

Andrea Giuseppe Di Francesco, Rishabh Jain, Franco Maria Nardini et al.

Recent methods for injecting graph structure into LLM prompts include graph soft prompting, in which a graph neural network (GNN) learns graph-specific tokens that…Recent methods for injecting graph structure into LLM prompts include graph soft prompting, in which a graph neural network (GNN) learns graph-specific tokens that capture relational information among entities in textual prompts.

Preprint: empirical study
arXiv

Training Small Language Models for Transferable Tool Selection

Zhaoyi Zhou, Akshayaa Magesh, Jeongyeol Kwon et al.

As LLM agents operate over corpora of more than ten thousand tools, selecting the right tool for a complex multi-step user instruction becomes a central bottleneck.As LLM agents operate over corpora of more than ten thousand tools, selecting the right tool for a complex multi-step user instruction becomes a central bottleneck.

Preprint: new model
arXiv

Extreme Compression of Per-Layer Embeddings via Cross-Layer Latent Vector Quantization

Jiacheng Liu, Yaxin Luo, Xiaohan Zhao et al.

Scaling embedding capacity alongside Transformer computation is an emerging trend in language models. This trend makes high compression rates increasingly useful.Scaling embedding capacity alongside Transformer computation is an emerging trend in language models. This trend makes high compression rates increasingly useful.

Preprint: method
arXiv

Same molecule, Different Knowledge: Cross-Identifier Binding Failures in LLMs For chemistry

Khouloud Saadi, Di Wang

Chemical AI workflows routinely represent the same molecule through multiple co-referring identifiers, including trivial names, IUPAC names, and SMILES, implicitly…Chemical AI workflows routinely represent the same molecule through multiple co-referring identifiers, including trivial names, IUPAC names, and SMILES, implicitly assuming that these representations provide interchangeable access…

Equivalent molecular identifiers expose different knowledge.
Preprint: method
arXiv

Inherited, Not Invented: Tracing the Provenance of Wait in Reasoning Models

Zhizhuo Kou, Sizai Hou, Long Chen et al.

Reinforcement learning (RL) is credited with teaching reasoning models to write {wait} before reconsidering a step, yet large RL accuracy gains do not require the word.Reinforcement learning (RL) is credited with teaching reasoning models to write {wait} before reconsidering a step, yet large RL accuracy gains do not require the word.

Preprint: empirical study
arXiv

A Computationally Efficient and Rate-Optimal Algorithm for Adversarial Linear MDPs with (Aggregate) Bandit Feedback

Haolin Liu, Chen-Yu Wei, Hanbin Zhou

We study episodic linear Markov decision processes with unknown transitions, adversarial losses, and bandit feedback.We study episodic linear Markov decision processes with unknown transitions, adversarial losses, and bandit feedback. The state-of-the-art result for this setting (Liu et al., 2024) either achieves √K regret with a computationally…

Preprint: method