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_5, x_5 is a server if and only if x_5 is rich. For all x_5, if x_5 goes running, then x_5 is reading a book. There is at least one x_5 for which if x_5 were rich, then x_5 is running.
There is at least one x_5 for which if x_5 were rich, then x_5 is reading a book can be inferred via the existential transitivity rule. For all x_5, if x_5 were a server, then x_5 is rich can be inferred via the universal biconditional elimination rule. For all x_5, if x_5 were rich, then x_5 is a server can be inferred via the universal biconditional elimination rule.