# [A nonspectrahedral hyperbolicity cone](nonspectrahedral-hyperbolicity-cone.pdf)

**Author:** OpenAI

**Date:** September 24, 2026

## Citation

```bibtex
@misc{OAI:A-Nonspectrahedral-Hyperbolicity-Cone-September-24-2026,
  author = {{OpenAI}},
  title = {{A nonspectrahedral hyperbolicity cone}},
  howpublished = {OpenAI Math Release preprint
                  \href{https://github.com/openai/math/blob/main/preprints/A-Nonspectrahedral-Hyperbolicity-Cone-September-24-2026/nonspectrahedral-hyperbolicity-cone.pdf}{OAI:A-Nonspectrahedral-Hyperbolicity-Cone-September-24-2026}},
  year = {2026}
}
```