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_10, if x_10 sleeps, then x_10 is a doctor. For all x_10, x_10 is a doctor if and only if x_10 will sleep. For all x_10, if x_10 were a doctor, then x_10 is sleeping.
For all x_10, x_10 will sleep if and only if x_10 is a doctor can be inferred via the universal biconditional introduction rule. For all x_10, x_10 is a doctor if and only if x_10 will sleep can be inferred via the universal biconditional introduction rule. For all x_10, if x_10 were a doctor, then x_10 is sleeping can be inferred via the universal biconditional elimination rule. For all x_10, if x_10 sleeps, then x_10 is a doctor can be inferred via the universal biconditional elimination rule.