Used as a key in MaxBetti with value being a VerticalList. Each item in the list is a set of total Betti numbers that are maximal. In other words, no ideal has total Betti numbers that are simultaneously greater than or equal, and there is an ideal with these total Betti numbers. See maxBettiNumbers(..., ResultsCount => ...) for more details.
The object MaximalBettiNumbers is a symbol.