What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: If Susan were a janitor, then Susan is reading a book. For all x_11, x_11 is a janitor if and only if x_11 will read a book.
For all x_11, if x_11 were a janitor, then x_11 is reading a book can be inferred via the universal biconditional elimination rule. For all x_11, if x_11 reads a book, then x_11 is a janitor can be inferred via the universal biconditional elimination rule.