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_16, if x_16 plays a game, then x_16 is poor. There is at least one x_16 for which x_16 will not play squash. For all x_16, if x_16 were poor, then x_16 is playing a game. For all x_16, x_16 is a doctor or x_16 will play squash. For all x_16, x_16 is not a doctor or x_16 will play a game.
For all x_16, x_16 will play squash or x_16 will play a game can be inferred via the universal resolution rule. For all x_16, x_16 will play a game if and only if x_16 is poor can be inferred via the universal biconditional introduction rule. For all x_16, x_16 is poor if and only if x_16 will play a game can be inferred via the universal biconditional introduction rule.