NonOverlappingDescents on Permutation
Descents taken greedily left to right, none starting where the last one ended.
Each maximal descending run of length m contributes floor(m / 2).
Called as CombinatorialStat(x, "NonOverlappingDescents"). The head's page has its examples.
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FindStat St001928
The number of non-overlapping descents in a permutation.
| Object | Value |
|---|---|
[1] | 0 |
[1,2] | 0 |
[2,1] | 1 |
[1,2,3] | 0 |
[1,3,2] | 1 |
[2,1,3] | 1 |
[2,3,1] | 1 |
[3,1,2] | 1 |
Data from FindStat, the combinatorial statistic finder; the page at findstat.org/St001928 has the rest.