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_7, if x_7 plays tennis, then x_7 is a writer. For all x_7, x_7 will sleep or x_7 will play tennis. There is at least one x_7 for which if x_7 sleeps, then x_7 is a writer.
There is at least one x_7 for which x_7 is a writer can be inferred via the existential disjunction elimination rule.