Translate the following inference to logic notation: For all x, x_21 will read a book if and only if x_21 is an astronaut. Elisabeth is not reading a book. Elisabeth is an astronaut if and only if Thomas is taking a plane. Therefore Thomas is not taking a plane or it is raining.
forall x: P(x) <-> Q(x). ~P(a). Q(a) <-> p. Therefore ~p or q.