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 x_16 for which x_16 is a mechanic. For all x_16, if x_16 sleeps, then x_16 is a sailor. For all x_16, x_16 is a sailor or x_16 is not a mechanic. For all x_16, if x_16 were a sailor, then x_16 is sleeping.
For all x_16, if x_16 were a mechanic, then x_16 is a sailor can be inferred via the universal rewriting rule. For all x_16, x_16 will sleep if and only if x_16 is a sailor can be inferred via the universal biconditional introduction rule. For all x_16, x_16 is a sailor if and only if x_16 will sleep can be inferred via the universal biconditional introduction rule.