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 y, if y plays tennis, then y is drinking water. For all y, if y drinks water, then y is a politician. There is at least one y for which y will play tennis or y is not a politician. For all y, if y drinks water, then y is playing tennis.
For all y, if y plays tennis, then y is a politician can be inferred via the universal transitivity rule. There is at least one y for which if y were a politician, then y is playing tennis can be inferred via the existential rewriting rule. For all y, y will play tennis if and only if y will drink water can be inferred via the universal biconditional introduction rule. For all y, y will drink water if and only if y will play tennis can be inferred via the universal biconditional introduction rule.