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 it rains, then Susan is reading a book. Susan is reading a book if and only if it is late. Jessica is poor. It is not late.
Jessica is poor and it is not late can be inferred via the conjunction rule. It is not late and Jessica is poor can be inferred via the conjunction rule. If Susan reads a book, then it is late can be inferred via the biconditional elimination rule. If it is late, then Susan is reading a book can be inferred via the biconditional elimination rule. Susan is not reading a book can be inferred via the biconditional elimination rule.