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_11 <-> q. q <-> q_11.
q_11 -> q can be inferred via the biconditional elimination rule. q -> q_11 can be inferred via the biconditional elimination rule. q -> q_11 can be inferred via the biconditional elimination rule. q_11 -> q can be inferred via the biconditional elimination rule.