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: U_3(y) or ~T_3(y). forall y: T_3(y) <-> U_3(y).
exists y: T_3(y) -> U_3(y) can be inferred via the existential rewriting rule. forall y: T_3(y) -> U_3(y) can be inferred via the universal biconditional elimination rule. forall y: U_3(y) -> T_3(y) can be inferred via the universal biconditional elimination rule.