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: For all x, if x works, then x is reading a book. There is at least one x for which x is a doctor or x will not read a book. For all x, if x were a doctor, then x is working.
For all x, if x were a doctor, then x is reading a book can be inferred via the universal transitivity rule. There is at least one x for which if x reads a book, then x is a doctor can be inferred via the existential rewriting rule.