RAIN-Merging: A Gradient-Free Method to Enhance Instruction Following in Large Reasoning Models with Preserved Thinking Format - Huang, Zhehao; Liu, Yuhang; Lin, Baijiong; Lou, Yixin; He, Zhengbao; Tian, Hanling; Li, Tao; Huang, Xiaolin (International Conference on Learning Representations, 2026)