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: exists y: P_1(y) -> T(y). forall y: T(y) -> P_1(y). forall y: T(y) -> P_1(y).
exists y: P_1(y) <-> T(y) can be inferred via the existential biconditional introduction rule. exists y: P_1(y) <-> T(y) can be inferred via the existential biconditional introduction rule. exists y: T(y) <-> P_1(y) can be inferred via the existential biconditional introduction rule. exists y: T(y) <-> P_1(y) can be inferred via the existential biconditional introduction rule.