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_5 for which if x_5 were a server, then x_5 is playing squash. For all x_5, x_5 will not play squash. For all x_5, x_5 is a server or x_5 is not a sailor.
There is at least one x_5 for which x_5 is not a server can be inferred via the existential modus tollens rule. For all x_5, if x_5 were a sailor, then x_5 is a server can be inferred via the universal rewriting rule.