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: t -> S(d). t or R(d). forall y_2: R(y_2) <-> S(y_2).
R_1(d) -> t can be inferred via the rewriting rule. forall y_2: R(y_2) -> S(y_2) can be inferred via the universal biconditional elimination rule. forall y_2: S(y_2) -> R(y_2) can be inferred via the universal biconditional elimination rule.