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_17, x_17 is a police officer. For all x_17, x_17 is a sailor if and only if x_17 is a police officer.
For all x_17, if x_17 were a sailor, then x_17 is a police officer can be inferred via the universal biconditional elimination rule. For all x_17, if x_17 were a police officer, then x_17 is a sailor can be inferred via the universal biconditional elimination rule.