Extending single-minus amplitudes to gravitonsOpenAI News / Mar 4, 2026重力子single-minusは非ゼロ半コリニアで分布として現れるGPT‑5.2 Proが導出を補助scattering-amplitudesgravitonrecursion-relationshalf-collineardirected-matrix-tree-theoremai-assistedw-(1+∞)