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_4, x_4 is not a politician or x_4 is a soldier. For all x_4, x_4 is happy or x_4 is a politician. There is at least one x_4 for which x_4 will not take a plane or x_4 is excited. For all x_4, x_4 is not happy or x_4 will take a plane.
For all x_4, x_4 is a politician or x_4 will take a plane can be inferred via the universal resolution rule.