What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_13, x_13 will read a book if and only if x_13 is happy. For all x_13, x_13 is not a janitor. There is at least one x_13 for which x_13 is a janitor if and only if x_13 will read a book. For all x_13, x_13 is happy if and only if x_13 is a server.
For all x_13, if x_13 reads a book, then x_13 is happy. For all x_13, if x_13 were happy, then x_13 is a server. There is at least one x_13 for which if x_13 were a janitor, then x_13 is reading a book. For all x_13, if x_13 were happy, then x_13 is reading a book. For all x_13, if x_13 were a server, then x_13 is happy. There is at least one x_13 for which if x_13 reads a book, then x_13 is a janitor. There is at least one x_13 for which x_13 will not read a book.