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_4, if x_4 cooks, then x_4 is a bartender. There is at least one x_4 for which x_4 will cook if and only if x_4 is a bartender.
There is at least one x_4 for which if x_4 cooks, then x_4 is a bartender can be inferred via the existential biconditional elimination rule. There is at least one x_4 for which if x_4 were a bartender, then x_4 is cooking can be inferred via the existential biconditional elimination rule.