**[OpenAI: GPT-5.6 Sol Ultra Solves 50-Year Graph Theory Problem in 1 Hour]** Odaily Planet Daily News – OpenAI researcher Ethan Knight stated on social platform X on the 12th that GPT-5.6 Sol Ultra has generated a proof paper and prompt for the representative unsolved problem in graph theory, the "Cycle Double Cover Conjecture." The model, configured with up to 64 parallel sub-agents, completed the result generation in approximately 1 hour without using internet searches. The publicly released paper by OpenAI spans 3 pages, first reducing the problem to cubic regular graphs, then applying the 8-flow theorem and GF(3) labeling, and finally constructing a structure where each edge is contained in exactly two cycles using linear algebra methods. The result has not yet been published in academic journals, undergone peer review, or been verified through formal systems like Lean or Coq. Thomas Bloom, a mathematician at the University of Manchester in the UK, praised the proof as "extremely impressive" but noted its lack of sufficient references. (ZDNet Korea Semiconductor).