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: William is reading a book if and only if it is cloudy. William is not reading a book. It is cloudy or Elisabeth is drinking water.
If William reads a book, then it is cloudy can be inferred via the biconditional elimination rule. If it is cloudy, then William is reading a book can be inferred via the biconditional elimination rule. It is not cloudy can be inferred via the biconditional elimination rule.