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 a doctor if and only if x_4 will work. For all x_4, x_4 is not an artist. For all x_4, x_4 will work if and only if x_4 is an artist.
For all x_4, if x_4 works, then x_4 is an artist. There is at least one x_4 for which if x_4 were a doctor, then x_4 is working. For all x_4, if x_4 were an artist, then x_4 is working. There is at least one x_4 for which if x_4 works, then x_4 is a doctor. For all x_4, x_4 will not work.