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_8, x_8 is a police officer if and only if x_8 is a sailor. For all x_8, x_8 is a police officer or x_8 is not a sailor.
For all x_8, if x_8 were a sailor, then x_8 is a police officer can be inferred via the universal rewriting rule. For all x_8, if x_8 were a police officer, then x_8 is a sailor can be inferred via the universal biconditional elimination rule. For all x_8, if x_8 were a sailor, then x_8 is a police officer can be inferred via the universal biconditional elimination rule.