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, y is a server if and only if y is an office clerk. William is a server.
There is at least one x for which x is a server can be inferred via the existential generalization rule. For all y, if y were a server, then y is an office clerk can be inferred via the universal biconditional elimination rule. For all y, if y were an office clerk, then y is a server can be inferred via the universal biconditional elimination rule.