The Prosocial Ranking Challenge: Reducing Polarization on Social Media without Sacrificing Engagement. - Jonathan Stray; Ian Baker; George Beknazar-Yuzbashev; Ceren Budak; Julia Kamin; Kylan Rutherford; Mateusz Stalinski; Tin Acosta; Chris Bailey 001; Michael S. Bernstein; Mark Brandt; Amy Bruckman; et al. (CoRR, 2026)