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_1, x_1 will not write a letter. There is at least one x_1 for which if x_1 reads a book, then x_1 is writing a letter. For all x_1, if x_1 were a politician, then x_1 is reading a book.
There is at least one x_1 for which x_1 will not read a book can be inferred via the existential modus tollens rule. There is at least one x_1 for which if x_1 were a politician, then x_1 is writing a letter can be inferred via the existential transitivity rule.