Translate the following inference to logic notation: Patricia is not fast. For all x, x_9 is fast if and only if x_9 will drink water. If William were a soldier, then Patricia is drinking water. If Patricia drinks water, then William is a soldier. Therefore William is not a soldier.
~P(a). forall x: P(x) <-> Q(x). p -> Q(a). Q(a) -> p. Therefore ~p.