What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? p_8 -> p_1. ~p_8. p_1 -> p_8. p_8 -> p_1.
~p_1. p_8 <-> p_1. p_1 <-> p_8. p_1 <-> p_8. p_8 <-> p_1.