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 poor if and only if John is happy. If John were happy, then Charles is poor. Thomas is reading a book. If John were happy, then Thomas is not reading a book.
John is not happy can be inferred via the modus tollens rule. If Charles were poor, then John is happy can be inferred via the biconditional elimination rule. If John were happy, then Charles is poor can be inferred via the biconditional elimination rule.