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: It is not late. Robert is reading a book if and only if it is late. It is cold or Robert is not reading a book. If it is cold, then Robert is reading a book.
If Robert reads a book, then it is cold can be inferred via the rewriting rule. If Robert reads a book, then it is late can be inferred via the biconditional elimination rule. If it is late, then Robert is reading a book can be inferred via the biconditional elimination rule. Robert is not reading a book can be inferred via the biconditional elimination rule.