# [A Counterexample to Wall's D(2) Problem](wall-d2-counterexample.pdf)

**Author:** OpenAI

**Date:** October 6, 2026

## Citation

```bibtex
@misc{OAI:A-Counterexample-to-Walls-D2-Problem-October-6-2026,
  author = {{OpenAI}},
  title = {{A Counterexample to Wall's $D(2)$ Problem}},
  howpublished = {OpenAI Math Release preprint
                  \href{https://github.com/openai/math/blob/main/preprints/A-Counterexample-to-Walls-D2-Problem-October-6-2026/wall-d2-counterexample.pdf}{OAI:A-Counterexample-to-Walls-D2-Problem-October-6-2026}},
  year = {2026}
}
```