GeoRef: Referring Expressions in Geometry via Task Formulation, Synthetic Supervision, and Reinforced MLLM-based Solutions. - Bing Liu; Wenqiang Yv; Xuzheng Yang; Shichang Wang; Junzhuo Liu 002; Peng Wang 023; Guoqing Wang 001; Yang Yang 002; Heng Tao Shen (CoRR, 2025)