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: R_2(y) <-> W(y). forall y: U_1(y) <-> R_2(y). exists y: ~U_1(y).
forall y: R_2(y) -> W(y) can be inferred via the universal biconditional elimination rule. forall y: U_1(y) -> R_2(y) can be inferred via the universal biconditional elimination rule. forall y: W(y) -> R_2(y) can be inferred via the universal biconditional elimination rule. forall y: R_2(y) -> U_1(y) can be inferred via the universal biconditional elimination rule. exists y: ~R_2(y) can be inferred via the existential biconditional elimination rule.