RL-10-TD算法-ActorCritic02-离线算法02-赵：重要性采样【E_{X~p₀}[X]=∑p₀(x)x=∑p₁(x)·[p₀(x)/p₁(x)]x=E_{X~p₁}[f(X)]】

2、重要性采样（Importance sampling）最核心的公式：EX∼p0[X]=∑xp0(x)x=∑xp1(x)p0(x)p1(x)x⏟f(x)=EX∼p1[f(X)]\color{red}{\mathbb{E}_{X \sim p_{0}}[X]