What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_13, x_13 is a doctor if and only if x_13 is a carpenter. For all x_13, x_13 is a scientist. There is at least one x_13 for which x_13 is a carpenter.
Some carpenters are scientists. Some scientists are carpenters. For all x_13, if x_13 were a doctor, then x_13 is a carpenter. For all x_13, if x_13 were a carpenter, then x_13 is a doctor.