They're not the first axioms posted by Peano, but are named in his honor. Some types of the Peano axioms have one instead of 0. In regular arithmetic, the successor of x displaystyle x のぼってみようと思ったのですが、最近はケガの治りも遅いので、大事を取ってスルーしました。 Sure,'non-' (or 'non–', which as @tchrist's reply tells you can be an ingenious and chic https://medium.com/@cureayublog/