What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_11, x_11 is happy if and only if x_11 will play squash. There is at least one x_11 for which x_11 will play squash. For all x_11, x_11 is not happy.
Since the premises are contradictory, we can infer anything from them.