InternalPoints on SetPartition
Elements with an earlier and a later element whose blocks open after theirs does.
An element e is internal when some f < e < g have blocks with larger least element than e's block (Mansour, Section 5.5).
Called as CombinatorialStat(x, "InternalPoints"). The head's page has its examples.
Live
FindStat St000562
The number of internal points of a set partition.
| Object | Value |
|---|---|
{{1,2}} | 0 |
{{1,2,3}} | 0 |
{{1},{2}} | 0 |
{{1,2,3,4}} | 0 |
{{1,2},{3}} | 0 |
{{1,3},{2}} | 0 |
{{1},{2,3}} | 0 |
{{1,2,3,4,5}} | 0 |
Data from FindStat, the combinatorial statistic finder; the page at findstat.org/St000562 has the rest.