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: For all x_3, x_3 is an office clerk if and only if x_3 is a lawyer. For all x_3, x_3 is an office clerk.
For all x_3, if x_3 were an office clerk, then x_3 is a lawyer can be inferred via the universal biconditional elimination rule. For all x_3, if x_3 were a lawyer, then x_3 is an office clerk can be inferred via the universal biconditional elimination rule.