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: There is at least one y_4 for which y_4 will drink water if and only if y_4 will play a game. For all y_4, y_4 will drink water if and only if y_4 will play a game.
For all y_4, if y_4 drinks water, then y_4 is playing a game can be inferred via the universal biconditional elimination rule. There is at least one y_4 for which if y_4 drinks water, then y_4 is playing a game can be inferred via the existential biconditional elimination rule. For all y_4, if y_4 plays a game, then y_4 is drinking water can be inferred via the universal biconditional elimination rule. There is at least one y_4 for which if y_4 plays a game, then y_4 is drinking water can be inferred via the existential biconditional elimination rule.