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_3(y) -> P_3(y). forall y: P_3(y) -> R_3(y). exists y: P_3(y).
exists y: R_3(y) can be inferred via the existential modus ponens rule. forall y: R_3(y) <-> P_3(y) can be inferred via the universal biconditional introduction rule. forall y: P_3(y) <-> R_3(y) can be inferred via the universal biconditional introduction rule.