RightDescents on SignedPermutation
Indices 0 <= k < n with s(k) > s(k+1), where s is the inverse of p and s(0) = 0.
FindStat's St001896: the left descents of the inverse. The inverse sends k to the position of k or -k, signed as the entry is.
Called as CombinatorialStat(x, "RightDescents"). The head's page has its examples.
Live
Distribution
Over SignedPermutations at each size, tallied here in your browser; sizes past 6 are not offered.
FindStat St001896
The number of right descents of a signed permutations.
| Object | Value |
|---|---|
[1] | 0 |
[-1] | 1 |
[1,2] | 0 |
[2,1] | 1 |
[-1,2] | 1 |
[-2,1] | 1 |
[1,-2] | 1 |
[2,-1] | 1 |
Data from FindStat, the combinatorial statistic finder; the page at findstat.org/St001896 has the rest.