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_3, x_3 is a carpenter. For all x_3, if x_3 were a server, then x_3 is reading a book. For all x_3, if x_3 were a carpenter, then x_3 is a server. There is at least one x_3 for which if x_3 were an astronaut, then x_3 is reading a book.
For all x_3, x_3 is a server can be inferred via the universal modus ponens rule. For all x_3, if x_3 were a carpenter, then x_3 is reading a book can be inferred via the universal transitivity rule.