title: Alloy specifications
body: <p>I'm a beginner learning Alloy, I want to know what means this n.^address (maybe with an example)? because logically if we consider address as a set of pairs like (A0,A1), then how we can join n which is for example N0 with this set?! since the left most element of pairs in address are not the same nature with n, I supposed that it would not possible.
  I'd really appreciate if anyone can guide me</p>