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: There is at least one z for which if z writes a letter, then z is curious. For all z, if z reads a book, then z is writing a letter. For all z, if z were curious, then z is reading a book.
For all z, if z were curious, then z is writing a letter can be inferred via the universal transitivity rule. There is at least one z for which if z writes a letter, then z is reading a book can be inferred via the existential transitivity rule. There is at least one z for which if z reads a book, then z is curious can be inferred via the existential transitivity rule.