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_6, if x_6 were a taxi driver, then x_6 is running. For all x_6, if x_6 goes running, then x_6 is driving a car. For all x_6, if x_6 drives a car, then x_6 is a mechanic. For all x_6, if x_6 were a mechanic, then x_6 is a taxi driver.
For all x_6, if x_6 were a taxi driver, then x_6 is driving a car can be inferred via the universal transitivity rule. For all x_6, if x_6 goes running, then x_6 is a mechanic can be inferred via the universal transitivity rule. For all x_6, if x_6 drives a car, then x_6 is a taxi driver can be inferred via the universal transitivity rule. For all x_6, if x_6 were a mechanic, then x_6 is running can be inferred via the universal transitivity rule.