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: forall y: P(y) or T_2(y). exists y: S_1(y) -> T_2(y). forall y: T_2(y) -> S_1(y). forall y: ~P(y).
forall y: T_2(y) can be inferred via the universal disjunctive syllogism rule. exists y: S_1(y) <-> T_2(y) can be inferred via the existential biconditional introduction rule. exists y: T_2(y) <-> S_1(y) can be inferred via the existential biconditional introduction rule.