“…At the most basic level, one might take this to mean 'prime natural numbers'. But it is not clear whether these are numbers in the structure (N, ×, 1), (N, ×, 1, <), (N , +, ×, 0, 1), or many other choices including (N , |, 1, S, <); see Arana (2011) for a number of variants. A natural response from a mathematician might be, 'In what ring?…”