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_4, x_4 will not sleep. For all x_4, if x_4 were a carpenter, then x_4 is taking a plane. There is at least one x_4 for which x_4 will sleep or x_4 is a carpenter.
There is at least one x_4 for which x_4 is a carpenter can be inferred via the existential disjunctive syllogism rule.