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 carpenter or z is a taxi driver. For all z, z is not a cashier. There is at least one z for which z is not a carpenter or z will go running. For all z, z is a cashier if and only if z is a taxi driver.
There is at least one z for which z is a taxi driver or z will go running can be inferred via the existential resolution rule. For all z, if z were a cashier, then z is a taxi driver can be inferred via the universal biconditional elimination rule. For all z, if z were a taxi driver, then z is a cashier can be inferred via the universal biconditional elimination rule. For all z, z is not a taxi driver can be inferred via the universal biconditional elimination rule.