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_12, if x_12 were a bartender, then x_12 is a musician. For all x_12, x_12 will sleep if and only if x_12 is a musician. There is at least one x_12 for which x_12 is a bartender or x_12 will sleep.
For all x_12, if x_12 sleeps, then x_12 is a musician can be inferred via the universal biconditional elimination rule. For all x_12, if x_12 were a musician, then x_12 is sleeping can be inferred via the universal biconditional elimination rule.