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: q <-> q_4. q or ~q_4.
q_4 -> q can be inferred via the rewriting rule. q -> q_4 can be inferred via the biconditional elimination rule. q_4 -> q can be inferred via the biconditional elimination rule.