A curated collection of optimization constants
- Here is an initial blog post introducing the project: A crowdsourced repository for optimization constants?, 22 Terence Tao, January 2026.
We are arbitrarily numbering the constants as
| Number | Description | Best lower bound | Best upper bound |
|---|---|---|---|
| 1 | Sidon set autocorrelation constant | 1.2802 | 1.5029 |
| 2 | Erdős minimum overlap constant | 0.379005 | 0.380876 |
| 3 | A sum-difference constant | 1.173077 | 1.33333 |
| 4 | Cap set constant | 0.724851 | 0.782597 |
| 5 | A Sidon set constant | 0 | 0.97633 |
| 6 | Union-closed sets conjecture constant | 0.38271 | 0.5 |
| 7 | The irrationality measure of |
2 | 7.103205334137 |
| 8 | Classical zero-free region constant | 0.755106 | 5.558691 |
| 9 | Shannon capacity of the 7-cycle | 3.2578 | 3.3177 |
| 10 | The real Grothendieck constant | 1.67696 | 1.782214 |
This site is maintained by Paata Ivanisvili and Terence Tao.
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