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. ~r. s <-> p. s <-> r.
q and ~r can be inferred via the conjunction rule. ~r and q can be inferred via the conjunction rule. s -> p can be inferred via the biconditional elimination rule. s -> r can be inferred via the biconditional elimination rule. p -> s can be inferred via the biconditional elimination rule. r -> s can be inferred via the biconditional elimination rule. ~s can be inferred via the biconditional elimination rule.