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_15 -> r_22. q_22 -> r_22. r_22 -> q_15. w_1. r_4 -> r_22. r_4 or q_22.
q_22 -> q_15 can be inferred via the transitivity rule. r_4 -> q_15 can be inferred via the transitivity rule. r_22 can be inferred via the disjunction elimination rule. q_15 <-> r_22 can be inferred via the biconditional introduction rule. r_22 <-> q_15 can be inferred via the biconditional introduction rule.