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, x will not drink water. For all x, x will drink water if and only if x is sad. For all x, x is sad or x will not play tennis.
For all x, if x plays tennis, then x is sad can be inferred via the universal rewriting rule. For all x, if x drinks water, then x is sad can be inferred via the universal biconditional elimination rule. For all x, if x were sad, then x is drinking water can be inferred via the universal biconditional elimination rule. For all x, x is not sad can be inferred via the universal biconditional elimination rule.