What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: Charles is playing a game if and only if Joseph is reading a book. For all x, x will not sleep. Joseph is reading a book if and only if Richard is sleeping.
If Charles plays a game, then Joseph is reading a book can be inferred via the biconditional elimination rule. If Joseph reads a book, then Richard is sleeping can be inferred via the biconditional elimination rule. If Joseph reads a book, then Charles is playing a game can be inferred via the biconditional elimination rule. If Richard sleeps, then Joseph is reading a book can be inferred via the biconditional elimination rule.