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_7, x_7 is an electrician or x_7 is a writer. For all x_7, x_7 is an electrician if and only if x_7 will sleep. For all x_7, if x_7 plays tennis, then x_7 is not sleeping. For all x_7, if x_7 were a writer, then x_7 is sleeping.
For all x_7, if x_7 were an electrician, then x_7 is sleeping can be inferred via the universal biconditional elimination rule. For all x_7, if x_7 sleeps, then x_7 is an electrician can be inferred via the universal biconditional elimination rule.