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: ~q_6. U_1(a_12) <-> p_6. p_6 -> q_6. forall y_3: U_2(y_3) <-> U_1(y_3).
~p_6 can be inferred via the modus tollens rule. U_1(a_12) -> p_6 can be inferred via the biconditional elimination rule. p_6 -> U_1(a_12) can be inferred via the biconditional elimination rule. forall y_3: U_2(y_3) -> U_1(y_3) can be inferred via the universal biconditional elimination rule. forall y_3: U_1(y_3) -> U_2(y_3) can be inferred via the universal biconditional elimination rule.