What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If Robert plays a game, then it is sunny. It is not sunny. Richard is reading a book. If John were a musician, then Robert is playing a game. If it is sunny, then Robert is playing a game.
Robert is not playing a game. It is not sunny and Richard is reading a book. Richard is reading a book and it is not sunny. Robert is playing a game if and only if it is sunny. It is sunny if and only if Robert is playing a game.