Efficient Symbolic Policy Learning with Differentiable Symbolic Expression - Guo, Jiaming; Zhang, Rui; Peng, Shaohui; Yi, Qi; Hu, Xing; Chen, Ruizhi; Du, Zidong; zhang, xishan; Li, Ling; Guo, Qi; Chen, Yunji (Advances in Neural Information Processing Systems, 2023)