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, if x_13 were a lawyer, then x_13 is a soldier. For all x_13, if x_13 were a soldier, then x_13 is a lawyer. David is a soldier or David is not a lawyer.
If David were a lawyer, then David is a soldier. For all x_13, x_13 is a lawyer if and only if x_13 is a soldier. For all x_13, x_13 is a soldier if and only if x_13 is a lawyer.