What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Robert is running or it is sunny. Sarah is playing tennis. Richard is rich if and only if Robert is running. Richard is not rich.
Sarah is playing tennis and Richard is not rich. Richard is not rich and Sarah is playing tennis. If Richard were rich, then Robert is running. If Robert goes running, then Richard is rich. Robert is not running.