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Lifan Yuan

23 accepted papers

2026

Do We Need Adam? Surprisingly Strong and Sparse Reinforcement Learning with SGD in LLMs

ICML 2026oral

Reinforcement learning (RL), particularly RL from verifiable reward (RLVR), has become a crucial phase of training large language models (LLMs) and a key focus of current scaling efforts. However, optimization practices in RL largely follow those of next-token-prediction stages (e.g., pretraining an…

Cited by 0SourceScholar
2026

From f(x) and g(x) to f(g(x)): LLMs Learn New Skills in RL by Composing Old Ones

ICLR 2026poster

Does reinforcement learning (RL) teach large language models (LLMs) genuinely new skills, or does it merely activate existing ones? This question lies at the core of ongoing debates about the role of RL in LLM post-training. On one side, strong empirical results can be achieved with RL alone even wi…

Cited by 0SourcecodeScholar
2026

How Far Can Unsupervised RLVR Scale LLM Training?

ICLR 2026poster

Unsupervised Reinforcement Learning with Verifiable Rewards (URLVR) offers a pathway for Large Language Models (LLMs) to improve without human supervision. Particularly, many works use model intrinsic information as rewards for URLVR, showing promising improvements, yet their potential and limitatio…

Cited by 0SourceScholar
2026

RLVE: Scaling Up Reinforcement Learning for Language Models with Adaptive Verifiable Environments

ICML 2026poster

We introduce Reinforcement Learning (RL) with Adaptive Verifiable Environments (RLVE), an approach using verifiable environments that procedurally generate problems and provide algorithmically verifiable rewards, to scale up RL for language models (LMs). RLVE enables each verifiable environment to d…

Cited by 0SourceScholar
2025

Advancing LLM Reasoning Generalists with Preference Trees

ICLR 2025poster

We introduce EURUS, a suite of large language models (LLMs) optimized for reasoning. Finetuned from Mistral-7B, Llama-3-8B, and Mixtral-8x22B, EURUS models achieve state-of-the-art results among open-source models on a diverse set of benchmarks covering mathematics, code generation, and logical reas…

2025

Free Process Rewards without Process Labels

ICML 2025poster

Different from its counterpart outcome reward models (ORMs), which evaluate the entire responses, a process reward model (PRM) scores a reasoning trajectory step by step, providing denser and more fine-grained rewards. However, training a PRM requires labels annotated at every intermediate step, pre…

2025

Reinforcement Learning Finetunes Small Subnetworks in Large Language Models

NeurIPS 2025poster

Reinforcement learning (RL) yields substantial improvements in large language models’ (LLMs) downstream task performance and alignment with human values. Surprisingly, such large gains result from updating only a small subnetwork comprising just 5%-30% of the parameters, with the rest effectively un…

Cited by 0SourceScholar
2025

The Right Time Matters: Data Arrangement Affects Zero-Shot Generalization in Instruction Tuning

ACL 2025finding

Understanding alignment techniques begins with comprehending zero-shot generalization brought by instruction tuning, but little of the mechanism has been understood. Existing work has largely been confined to the task level, without considering that tasks are artificially defined and, to LLMs, merel…

2025

The Unreasonable Effectiveness of Entropy Minimization in LLM Reasoning

NeurIPS 2025poster

Entropy minimization (EM) trains the model to concentrate even more probability mass on its most confident outputs. We show that this simple objective alone, without any labeled data, can substantially improve large language models’ (LLMs) performance on challenging math, physics, and coding tasks.…

Cited by 0SourcecodeScholar
2024

CRAFT: Customizing LLMs by Creating and Retrieving from Specialized Toolsets

ICLR 2024poster

Large language models (LLMs) are often augmented with tools to solve complex tasks. By generating code snippets and executing them through task-specific Application Programming Interfaces (APIs), they can offload certain functions to dedicated external modules, such as image encoding and performing…

2024

Controllable Preference Optimization: Toward Controllable Multi-Objective Alignment

EMNLP 2024main

Alignment in artificial intelligence pursues the consistency between model responses and human preferences as well as values. In practice, the multifaceted nature of human preferences inadvertently introduces what is known as the ”alignment tax”–a compromise where enhancements in alignment within on…

2024

Executable Code Actions Elicit Better LLM Agents

ICML 2024poster

Large Language Model (LLM) agents, capable of performing a broad range of actions, such as invoking tools and controlling robots, show great potential in tackling real-world challenges. LLM agents are typically prompted to produce actions by generating JSON or text in a pre-defined format, which is…

Cited by 154SourcePDFScholar
2024

MINT: Evaluating LLMs in Multi-turn Interaction with Tools and Language Feedback

ICLR 2024poster

To solve complex tasks, large language models (LLMs) often require multiple rounds of interactions with the user, sometimes assisted by external tools. However, current evaluation protocols often emphasize benchmark performance with single-turn exchanges, neglecting the nuanced interactions among th…

Cited by 135SourcePDFScholar
2024

Noise Contrastive Alignment of Language Models with Explicit Rewards

NeurIPS 2024poster

User intentions are typically formalized as evaluation rewards to be maximized when fine-tuning language models (LMs). Existing alignment methods, such as Direct Preference Optimization (DPO), are mainly tailored for pairwise preference data where rewards are implicitly defined rather than explicitl…

2024

ULTRAFEEDBACK: Boosting Language Models with Scaled AI Feedback

ICML 2024poster

Learning from human feedback has become a pivot technique in aligning large language models (LLMs) with human preferences. However, acquiring vast and premium human feedback is bottlenecked by time, labor, and human capability, resulting in small sizes or limited topics of current datasets. This fur…

2023

A Close Look into the Calibration of Pre-trained Language Models

ACL 2023long

Pre-trained language models (PLMs) may fail in giving reliable estimates of their predictive uncertainty. We take a close look into this problem, aiming to answer two questions: (1) Do PLMs learn to become calibrated in the training process? (2) How effective are existing calibration methods? For th…

2023

Beat LLMs at Their Own Game: Zero-Shot LLM-Generated Text Detection via Querying ChatGPT

EMNLP 2023short main

Large language models (LLMs), e.g., ChatGPT, have revolutionized the domain of natural language processing because of their excellent performance on various tasks. Despite their great potential, LLMs also incur serious concerns as they are likely to be misused. There are already reported cases of ac…

Cited by 0SourcecodeScholar
2023

Bridge the Gap Between CV and NLP! A Gradient-based Textual Adversarial Attack Framework

ACL 2023findings

Despite recent success on various tasks, deep learning techniques still perform poorly on adversarial examples with small perturbations. While optimization-based methods for adversarial attacks are well-explored in the field of computer vision, it is impractical to directly apply them in natural lan…

2023

From Adversarial Arms Race to Model-centric Evaluation: Motivating a Unified Automatic Robustness Evaluation Framework

ACL 2023findings

Textual adversarial attacks can discover models’ weaknesses by adding semantic-preserved but misleading perturbations to the inputs. The long-lasting adversarial attack-and-defense arms race in Natural Language Processing (NLP) is algorithm-centric, providing valuable techniques for automatic robust…

2023

Revisiting Out-of-distribution Robustness in NLP: Benchmarks, Analysis, and LLMs Evaluations

NeurIPS 2023poster

This paper reexamines the research on out-of-distribution (OOD) robustness in the field of NLP. We find that the distribution shift settings in previous studies commonly lack adequate challenges, hindering the accurate evaluation of OOD robustness. To address these issues, we propose a benchmark con…

2022

A Unified Evaluation of Textual Backdoor Learning: Frameworks and Benchmarks

NeurIPS 2022accept

Textual backdoor attacks are a kind of practical threat to NLP systems. By injecting a backdoor in the training phase, the adversary could control model predictions via predefined triggers. As various attack and defense models have been proposed, it is of great significance to perform rigorous evalu…

2022

FactMix: Using a Few Labeled In-domain Examples to Generalize to Cross-domain Named Entity Recognition

COLING 2022main

Few-shot Named Entity Recognition (NER) is imperative for entity tagging in limited resource domains and thus received proper attention in recent years. Existing approaches for few-shot NER are evaluated mainly under in-domain settings. In contrast, little is known about how these inherently faithfu…