Researcher

Fangyun Lin

Fangyun Lin is an AI researcher whose work with DeepSeek spans language models, reasoning and inference. They coauthored the 2024 DeepSeek LLM, DeepSeek-V2 and DeepSeek-V3 reports, including work on open-source model scaling and mixture-of-experts designs. In 2025, they coauthored DeepSeek-R1's reinforcement-learning research and DeepSeek-V3.2's sparse-attention work. As of October 2026, they are on DeepSeek's Research & Engineering team and coauthor DeepSeek-V4.1-Flash.

Timeline

  1. January 2024

    Open-source language models

    They coauthor the DeepSeek LLM report in January 2024, which uses scaling laws to study open-source 7B and 67B language models.

  2. May 2024

    DeepSeek-V2's mixture-of-experts model

    In May 2024, Lin coauthors DeepSeek-V2, a mixture-of-experts model with 236 billion total parameters and 21 billion activated per token.

  3. December 2024

    DeepSeek-V3's technical report

    The December 2024 DeepSeek-V3 report describes a 671-billion-parameter mixture-of-experts model with 37 billion active per token; Lin coauthors it.

  4. 2025

    DeepSeek-R1 and reinforcement learning

    In 2025, they coauthor the DeepSeek-R1 paper, which shows that pure reinforcement learning can elicit reasoning without human-labelled trajectories.

  5. December 2025

    DeepSeek Sparse Attention

    The DeepSeek-V3.2 report introduces DeepSeek Sparse Attention in December 2025, a mechanism that reduces computational complexity in long-context scenarios; Lin coauthors the report.

  6. As of October 2026

    Research and engineering at DeepSeek

    They work in DeepSeek's Research & Engineering team as of October 2026 and coauthor the group's V4.1-Flash report on KV-cache compression. The report describes a multimodal mixture-of-experts model with a Causal Encoder-Decoder architecture and up to one million tokens of context.

Sources and credits

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  1. [2401.02954] DeepSeek LLM: Scaling Open-Source Language Models with Longtermism arxiv.org. Checked 19 October 2026.
  2. [2405.04434] DeepSeek-V2: A Strong, Economical, and Efficient Mixture-of-Experts Language Model arxiv.org. Checked 19 October 2026.
  3. DeepSeek-V3 Technical Report | Cool Papers - Immersive Paper Discovery papers.cool. Checked 19 October 2026.
  4. DeepSeek-R1 incentivizes reasoning in LLMs through reinforcement learning | Nature nature.com. Checked 19 October 2026.
  5. [2512.02556] DeepSeek-V3.2: Pushing the Frontier of Open Large Language Models ar5iv.labs.arxiv.org. Checked 19 October 2026.
  6. [2609.19969] DeepSeek-V4.1-Flash: Pushing the Limits of KV Cache Compression ar5iv.labs.arxiv.org. Checked 19 October 2026.