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: There is at least one x_13 for which x_13 is a soldier. For all x_13, x_13 will not climb a mountain or x_13 will play squash. For all x_13, x_13 is not a soldier.
Nothing can be inferred from these premises.