SIT TechniqueEx[X]=Ey[E[X∣Y]]\mathbb{E}_x[X] = \mathbb{E}_y [\mathbb{E}[X|Y]]Ex[X]=Ey[E[X∣Y]] E[g(x, y, z)]=Ez[Ey∣z[Ex∣y,z[g(x, y, z)∣y, z]]]\mathbb{E}[g(x,~y,~z)] = \mathbb{E}_z [\mathbb{E}_{y|z}[ \mathbb{E}_{x|y,z}[g(x,~y,~z)|y,~z]]]E[g(x, y, z)]=Ez[Ey∣z[Ex∣y,z[g(x, y, z)∣y, z]]]