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_7 for which x_7 is rich. For all x_7, if x_7 were rich, then x_7 is a musician. For all x_7, x_7 is a janitor if and only if x_7 is a musician.
There is at least one x_7 for which x_7 is a musician. For all x_7, if x_7 were a janitor, then x_7 is a musician. For all x_7, if x_7 were a musician, then x_7 is a janitor.