Claims

../

2006_09_19_parrilo_robertson_saracino: Theorems 4 and 5 of Parrilo, Robertson and Saracino (J. Combin. Theory Ser. A 2008) bound delta_3 between 1675/32768 and 117/2192, refuting the guess delta_3 = 1/16; refereed; the case k = 3 only.

2026_10_05_toledo: Carlos Toledo's partial proof claim of 2026-10-05 that delta_3 = 117/2192, so the upper bound of Parrilo, Robertson and Saracino is exact, by a reduction to a quadratic-form inequality closed with five exact certificates.

---