But In copyedit, it had been determined that While appropriate, this was also alien for usual persons to immediately apprehend. So we adopted a courageous but unambiguous Conference that programmers would immediately apprehend: The natural quantities type a set, typically symbolized to be a bold N or blackboard bold ⁠ https://share.evernote.com/note/a8fd1cb2-5733-5366-f5df-7a36578ae666