collaborators

10 papers

cs.AI2025

OpenApps: Simulating Environment Variations to Measure UI-Agent Reliability

Karen Ullrich, Jingtong Su, Claudia Shi +7

Reliability is key to realizing the promise of autonomous UI-Agents, multimodal agents that directly interact with apps in the same manner as humans, as users must be able to trust…

cs.LG2025

Don't Waste Mistakes: Leveraging Negative RL-Groups via Confidence Reweighting

Yunzhen Feng, Parag Jain, Anthony Hartshorn +2

Reinforcement learning with verifiable rewards (RLVR) has become a standard recipe for improving large language models (LLMs) on reasoning tasks, with Group Relative Policy Optimiz…

cs.LG2025

How Reinforcement Learning After Next-Token Prediction Facilitates Learning

Nikolaos Tsilivis, Eran Malach, Karen Ullrich +1

Recent advances in reasoning domains with neural networks have primarily been enabled by a training recipe that optimizes Large Language Models, previously trained to predict the n…

cs.LG2025

What Characterizes Effective Reasoning? Revisiting Length, Review, and Structure of CoT

Yunzhen Feng, Julia Kempe, Cheng Zhang +2

Large reasoning models (LRMs) spend substantial test-time compute on long chain-of-thought (CoT) traces, but what *characterizes* an effective CoT remains unclear. While prior work…

cs.LG2025

From Concepts to Components: Concept-Agnostic Attention Module Discovery in Transformers

Jingtong Su, Julia Kempe, Karen Ullrich

Transformers have achieved state-of-the-art performance across language and vision tasks. This success drives the imperative to interpret their internal mechanisms with the dual go…

cs.LG2025

Asymmetric REINFORCE for off-Policy Reinforcement Learning: Balancing positive and negative rewards

Charles Arnal, Gaëtan Narozniak, Vivien Cabannes +3

Reinforcement learning (RL) is increasingly used to align large language models (LLMs). Off-policy methods offer greater implementation simplicity and data efficiency than on-polic…