Yes, I would agree. His logic is that we should cater to the empty sequence case, and it would be "unnatural" to write 2 <= x <= 1, so we have to write 2 <= x

Yes, I would agree. His logic is that we should cater to the empty sequence case, and it would be "unnatural" to write 2 <= x <= 1, so we have to write 2 <= x < 2. That is just not an improvement. Ask somebody to write down an empty sequence, starting at 2, they'll think you're crazy. The Common Case is give the First and Last. Option C is, to me, obviously best. How you can replace 2 .. 12 and not use 2 & 12 is beyond me. (/s Dijkstra's opinions considered harmful /s)