@article{whendoesgeneratingmorehelpdisentanglingf,
  title = {When Does Generating More Help? Disentangling Fixed-Source Synthesis from Source Expansion in Synthetic Data Scaling},
  author = {Xu Guo and Jian Tong and Zhihui Lu and Qipeng Guo},
  year = {2026},
  eprint = {2607.01727},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2607.01727},
}