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: u <-> R_12(a_12). S_12(a_12) -> q. forall x_12: R_12(x_12) <-> S_12(x_12). ~q.
~S_12(a_12) can be inferred via the modus tollens rule. u -> R_12(a_12) can be inferred via the biconditional elimination rule. R_12(a_12) -> u can be inferred via the biconditional elimination rule. forall x_12: R_12(x_12) -> S_12(x_12) can be inferred via the universal biconditional elimination rule. forall x_12: S_12(x_12) -> R_12(x_12) can be inferred via the universal biconditional elimination rule.