What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Richard is not sleeping. Joseph is happy if and only if John is a server. It is snowing if and only if John is a server. Joseph is happy if and only if Richard is sleeping. It is snowing if and only if Susan is climbing a mountain.
If Joseph were happy, then John is a server. If it snows, then John is a server. If Joseph were happy, then Richard is sleeping. If it snows, then Susan is climbing a mountain. If John were a server, then Joseph is happy. If John were a server, then it is snowing. If Richard sleeps, then Joseph is happy. If Susan climbs a mountain, then it is snowing. Joseph is not happy.