Published October 29, 2026
| Version v1.0.0
Software
Open
R(12,12) ≥ 1642: a colouring of K_1641, a Lean proof and computer checks
Authors/Creators
Description
A red/blue colouring of the complete graph on 1641 vertices with no monochromatic K_12, so R(12,12) ≥ 1642. It adds one vertex to Tatarevic's two-parameter Ramsey increment applied to the Mathon colouring M(797). Includes a Lean 4 proof accepted by two independent kernels and an exhaustive computer search. The work was done with Claude (Claude Opus 5.5, Anthropic); see the README.
Notes
If you use this colouring or the Lean proof, please cite it as below, together with Tatarevic's paper.
Files
YueMa0/r1212-1642-v1.0.0.zip
Additional details
Related works
- Is supplement to
- Software: https://github.com/YueMa0/r1212-1642/tree/v1.0.0 (URL)
Software
- Repository URL
- https://github.com/YueMa0/r1212-1642