What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all y_4, if y_4 reads a book, then y_4 is playing tennis. For all y_4, y_4 will play tennis if and only if y_4 will read a book.
For all y_4, if y_4 plays tennis, then y_4 is reading a book. For all y_4, if y_4 reads a book, then y_4 is playing tennis.