What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? There is at least one x_4 for which x_4 is an artist or x_4 will play tennis. For all x_4, x_4 is not an artist. For all x_4, if x_4 plays tennis, then x_4 is writing a letter.
There is at least one x_4 for which x_4 will play tennis.