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: Jennifer is not writing a letter. It is cold and James is reading a book. Jennifer is writing a letter or Robert is happy.
Robert is happy can be inferred via the disjunctive syllogism rule. It is cold can be inferred via the simplification rule. James is reading a book can be inferred via the simplification rule.