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 z, z is a lawyer or z will not go running. There is at least one z for which if z were a lawyer, then z is a server. For all z, if z were a server, then z is a lawyer. For all z, if z were a server, then z is rich.
There is at least one z for which if z were a lawyer, then z is rich can be inferred via the existential transitivity rule. For all z, if z goes running, then z is a lawyer can be inferred via the universal rewriting rule. There is at least one z for which z is a lawyer if and only if z is a server can be inferred via the existential biconditional introduction rule. There is at least one z for which z is a server if and only if z is a lawyer can be inferred via the existential biconditional introduction rule.