The rule is "Either P is an ingredient or Y is an ingredient, but not both." It's easy enough to see that both of them cannot be in, but does this rule mandate that AT LEAST one of them is in? If so, can you also point me to the lecture in the core curriculum where this is explained?

Thanks so much

Admin Note: https://classic.7sage.com/lsat_explanations/lsat-89-section-1-game-2/