What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all y, y is not a soldier. For all y, y is a soldier or y will write a letter. For all y, y will write a letter if and only if y will read a book.
For all y, y will write a letter. For all y, if y writes a letter, then y is reading a book. For all y, if y reads a book, then y is writing a letter.