1) There is some order (lexicographic, colexicographic, minimal differences, gray code, etc.) that: The. incrementally add elements (an "n + 1" -th element) to the set (cardinality n) where the subsets and tuples are created B. and each new added element generates a new range (unranked) from "k" to "k" combinations or permutations (with or without repetition), as always larger layers?
2) If there is such a order , do you know your "rank", "unrank" algorithms, next?