What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? There is at least one y for which if y reads a book, then y is sleeping. For all y, y will sleep if and only if y will write a letter. For all y, if y writes a letter, then y is sleeping. For all y, y will not write a letter.
For all y, if y sleeps, then y is writing a letter. For all y, if y writes a letter, then y is sleeping. For all y, y will not sleep.