What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_6, if x_6 were a doctor, then x_6 is an astronaut. For all x_6, if x_6 were happy, then x_6 is an astronaut. For all x_6, if x_6 were an astronaut, then x_6 is a doctor. For all x_6, x_6 is not a doctor. There is at least one x_6 for which if x_6 were an astronaut, then x_6 is happy.
For all x_6, x_6 is not an astronaut. For all x_6, if x_6 were happy, then x_6 is a doctor. There is at least one x_6 for which if x_6 were a doctor, then x_6 is happy. For all x_6, x_6 is a doctor if and only if x_6 is an astronaut. For all x_6, x_6 is an astronaut if and only if x_6 is a doctor. There is at least one x_6 for which x_6 is an astronaut if and only if x_6 is happy. There is at least one x_6 for which x_6 is happy if and only if x_6 is an astronaut.