GPT-6Astra and three researchers solved a 2017 math problem on FrontierMath proving the core always exists in approval-based committee elections. The AI invented a new voting rule using harmonic entropy and provided a polynomial-time algorithm. This marks the first time AI solved a major breakthrough math problem, shifting large models from problem-solving tools to collaborative pattern-discoverers. Epoch AI now recognizes Human+AI joint achievements, signaling a rewrite of scientific research methods where humans act as prompt engineers guiding AI-driven discovery.