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 y_2, y_2 will work if and only if y_2 is a server. For all y_2, y_2 will sleep if and only if y_2 will work. There is at least one y_2 for which y_2 will not sleep.
For all y_2, if y_2 works, then y_2 is a server can be inferred via the universal biconditional elimination rule. For all y_2, if y_2 sleeps, then y_2 is working can be inferred via the universal biconditional elimination rule. For all y_2, if y_2 were a server, then y_2 is working can be inferred via the universal biconditional elimination rule. For all y_2, if y_2 works, then y_2 is sleeping can be inferred via the universal biconditional elimination rule. There is at least one y_2 for which y_2 will not work can be inferred via the existential biconditional elimination rule.