We begin with some basic definitions. Definition 1.1. Let f, g ∈ F [x]. We say that f divides g, written f ∣∣g, if there exists an h ∈ F [x] such that g = fh, i.e. g is a multiple of f . Thus, for example, every f ∈ F [x] divides the zero polynomial 0, but g is divisible by 0 ⇐⇒ g = 0. By definition, f is a unit ⇐⇒ f ∣∣1. Recall also that the group of units (F [x])∗ of the ring F [x] is F ∗, th...