What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? There is at least one y_4 for which y_4 is poor if and only if y_4 is happy. For all y_4, y_4 is happy if and only if y_4 is poor.
For all y_4, if y_4 were happy, then y_4 is poor. There is at least one y_4 for which if y_4 were poor, then y_4 is happy. For all y_4, if y_4 were poor, then y_4 is happy. There is at least one y_4 for which if y_4 were happy, then y_4 is poor.