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: There is at least one y for which if y reads a book, then y is working. For all y, y will not work. For all y, if y works, then y is reading a book. For all y, y will read a book if and only if y is a lawyer.
There is at least one y for which y will not read a book can be inferred via the existential modus tollens rule. There is at least one y for which y will read a book if and only if y will work can be inferred via the existential biconditional introduction rule. There is at least one y for which y will work if and only if y will read a book can be inferred via the existential biconditional introduction rule. For all y, if y reads a book, then y is a lawyer can be inferred via the universal biconditional elimination rule. For all y, if y were a lawyer, then y is reading a book can be inferred via the universal biconditional elimination rule.