collaborators

5 papers

cs.CL2026

A Unified Definition of Hallucination: It's The World Model, Stupid!

Emmy Liu, Varun Gangal, Chelsea Zou +7

Despite numerous attempts at mitigation since the inception of language models, hallucinations remain a persistent problem even in today's frontier LLMs. Why is this? We review exi…

cs.CL2026

HalluWorld: A Controlled Benchmark for Hallucination via Reference World Models

Emmy Liu, Varun Gangal, Michael Yu +4

Hallucination remains a central failure mode of large language models, but existing benchmarks operationalize it inconsistently across summarization, question answering, retrieval-…

cs.CL2026

To Memorize or to Retrieve: Scaling the Interaction Between Pretraining and Retrieval

Karan Singh, Michael Yu, Varun Gangal +4

Retrieval-augmented generation (RAG) improves language model (LM) performance by providing relevant context at test time for knowledge-intensive situations. In this work, we system…

cs.LG2026

Humanity's Last Exam

Long Phan, Alice Gatti, Ziwen Han +1144

Benchmarks are important tools for tracking the rapid advancements in large language model (LLM) capabilities. However, benchmarks are not keeping pace in difficulty: LLMs now achi…

cs.CL2024

Maximize Your Data's Potential: Enhancing LLM Accuracy with Two-Phase Pretraining

Steven Feng, Shrimai Prabhumoye, Kezhi Kong +4

Pretraining large language models effectively requires strategic data selection, blending and ordering. However, key details about data mixtures especially their scalability to lon…