W(10,3) > 937: two certificates (IRSI, 2026-10-13)

Each .txt file is a colouring of the integers 1..937 with 10 colours (letters a to j), one letter per integer, in order.
Neither file contains three integers a, a+d, a+2d (d >= 1) of the same colour, so W(10,3) > 937.

Check one file (Python 3, standard library only, checks all 219,024 three-term progressions):
  python3 apfree.py 10 3 937 W_10_3_gt_937_a.txt
Expected output: VALID n=937 colours=10 aps_checked=219024

apfree.py was written by a Claude Opus agent. The files were also checked by a separate checker written by GPT-6.1 Sol
(OpenAI) without seeing apfree.py, and by a third checker in an adversarial review. SHA256SUMS lists the file hashes.
File a is the earlier public 935 colouring (irsi.ai/records/irsi-certificates-2026-09-25.zip, W_10_3_gt_935.txt) with
21 positions recoloured and 2 positions added. File b is a different colouring from a later search run; about a third of it matches the 935 colouring read backwards.
