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_12, x_12 will play tennis if and only if x_12 will sleep. For all x_12, x_12 is a politician or x_12 will play tennis. For all x_12, if x_12 drinks water, then x_12 is playing squash. For all x_12, x_12 is not a politician. For all x_12, if x_12 sleeps, then x_12 is playing squash.
For all x_12, x_12 will play tennis can be inferred via the universal disjunctive syllogism rule. For all x_12, if x_12 plays tennis, then x_12 is sleeping can be inferred via the universal biconditional elimination rule. For all x_12, if x_12 sleeps, then x_12 is playing tennis can be inferred via the universal biconditional elimination rule.