Math Behind GOSS (Gradient-Based One Side Sampling)?
Wang et al., (2019) have provided a nice and clear explanation. Please, check out their paper to find the answer you are looking for:
Part II. BAYESIAN OPTIMIZED LIGHTGBM
Section: A. The Principle of the LightGBM
Wang, R., Liu, Y., Ye, X., Tang, Q., Gou, J., Huang, M., &amp; Wen, Y. (2019). Power System Transient Stability Assessment Based on Bayesian Optimized LightGBM. 2019 IEEE 3Rd Conference On Energy Internet And Energy System Integration (EI2). doi: 10.1109/ei247390.2019.9062027