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: If Michael reads a book, then Michael is sad. If Michael were sad, then Michael is reading a book.
Michael is reading a book if and only if Michael is sad can be inferred via the biconditional introduction rule. Michael is sad if and only if Michael is reading a book can be inferred via the biconditional introduction rule.