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_6, if x_6 sleeps, then x_6 is taking a plane. For all x_6, x_6 will sleep and x_6 is a sailor. There is at least one x_6 for which if x_6 takes a plane, then x_6 is an artist.
There is at least one x_6 for which if x_6 sleeps, then x_6 is an artist can be inferred via the existential transitivity rule. For all x_6, x_6 will sleep can be inferred via the universal simplification rule. For all x_6, x_6 is a sailor can be inferred via the universal simplification rule.