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_8, x_8 is a carpenter or x_8 is not a janitor. For all x_8, x_8 is a carpenter if and only if x_8 will sleep. There is at least one x_8 for which x_8 will sleep or x_8 is a janitor.
For all x_8, if x_8 were a janitor, then x_8 is a carpenter can be inferred via the universal rewriting rule. For all x_8, if x_8 were a carpenter, then x_8 is sleeping can be inferred via the universal biconditional elimination rule. For all x_8, if x_8 sleeps, then x_8 is a carpenter can be inferred via the universal biconditional elimination rule.