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_3, x_3 is not a scientist. There is at least one x_3 for which if x_3 were a musician, then x_3 is a scientist. For all x_3, x_3 is a musician or x_3 is not a scientist.
There is at least one x_3 for which x_3 is not a musician can be inferred via the existential modus tollens rule. For all x_3, if x_3 were a scientist, then x_3 is a musician can be inferred via the universal rewriting rule.