Translate the following inference to logic notation: There is at least one x for which x_13 will sleep if and only if x_13 is happy. For all x, x_13 will sleep. Therefore there is at least one x for which x_13 is happy or x_13 is a musician.
exists x: P(x) <-> Q(x). forall x: P(x). Therefore exists x: Q(x) or R(x).