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_15, x_15 will not drink water. For all x_15, x_15 will drink water or x_15 is not a mechanic. Michael is a lawyer if and only if Barbara is sleeping. For all x_15, x_15 is a mechanic if and only if x_15 is a lawyer.
If Michael were a lawyer, then Barbara is sleeping can be inferred via the biconditional elimination rule. If Barbara sleeps, then Michael is a lawyer can be inferred via the biconditional elimination rule. For all x_15, if x_15 were a mechanic, then x_15 is drinking water can be inferred via the universal rewriting rule. For all x_15, if x_15 were a mechanic, then x_15 is a lawyer can be inferred via the universal biconditional elimination rule. For all x_15, if x_15 were a lawyer, then x_15 is a mechanic can be inferred via the universal biconditional elimination rule.