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: For all x_8, x_8 will play a game if and only if x_8 will sleep. There is at least one x_8 for which x_8 is a taxi driver or x_8 is poor. For all x_8, if x_8 were poor, then x_8 is playing a game. For all x_8, if x_8 were a taxi driver, then x_8 is sleeping.
For all x_8, if x_8 plays a game, then x_8 is sleeping can be inferred via the universal biconditional elimination rule. For all x_8, if x_8 sleeps, then x_8 is playing a game can be inferred via the universal biconditional elimination rule.