I wonder if doing the intersections first would be an optimisation? ie S_1, S_1 \cap S_2, S_2, S_1 \cap S_2 \cap S_3, S_1 \cap S_3, S_2 \cap S_3, S_3
I wonder if doing the intersections first would be an optimisation? ie S_1, S_1 \cap S_2, S_2, S_1 \cap S_2 \cap S_3, S_1 \cap S_3, S_2 \cap S_3, S_3