Translate the following inference to logic notation: Thomas is not listening to a song. For all x, x_21 will listen to a song if and only if x_21 is a janitor. Jessica is reading a book if and only if Elisabeth is cooking. Elisabeth is cooking if and only if Thomas is a janitor. Therefore Jessica is not reading a book or it is cold.
~P(a). forall x: P(x) <-> Q(x). p <-> q. q <-> Q(a). Therefore ~p or r.