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Identifier
Values
=>
[1]=>0 [-1]=>1 [1,2]=>0 [1,-2]=>3 [-1,2]=>1 [-1,-2]=>4 [2,1]=>1 [2,-1]=>2 [-2,1]=>3 [-2,-1]=>2 [1,2,3]=>0 [1,2,-3]=>5 [1,-2,3]=>3 [1,-2,-3]=>8 [-1,2,3]=>1 [-1,2,-3]=>6 [-1,-2,3]=>4 [-1,-2,-3]=>9 [1,3,2]=>1 [1,3,-2]=>4 [1,-3,2]=>7 [1,-3,-2]=>4 [-1,3,2]=>2 [-1,3,-2]=>5 [-1,-3,2]=>8 [-1,-3,-2]=>5 [2,1,3]=>1 [2,1,-3]=>6 [2,-1,3]=>2 [2,-1,-3]=>7 [-2,1,3]=>3 [-2,1,-3]=>8 [-2,-1,3]=>2 [-2,-1,-3]=>7 [2,3,1]=>2 [2,3,-1]=>3 [2,-3,1]=>6 [2,-3,-1]=>5 [-2,3,1]=>4 [-2,3,-1]=>3 [-2,-3,1]=>6 [-2,-3,-1]=>7 [3,1,2]=>3 [3,1,-2]=>5 [3,-1,2]=>4 [3,-1,-2]=>4 [-3,1,2]=>6 [-3,1,-2]=>4 [-3,-1,2]=>5 [-3,-1,-2]=>5 [3,2,1]=>2 [3,2,-1]=>3 [3,-2,1]=>5 [3,-2,-1]=>6 [-3,2,1]=>4 [-3,2,-1]=>3 [-3,-2,1]=>7 [-3,-2,-1]=>6 [1,2,3,4]=>0 [1,2,3,-4]=>7 [1,2,-3,4]=>5 [1,2,-3,-4]=>12 [1,-2,3,4]=>3 [1,-2,3,-4]=>10 [1,-2,-3,4]=>8 [1,-2,-3,-4]=>15 [-1,2,3,4]=>1 [-1,2,3,-4]=>8 [-1,2,-3,4]=>6 [-1,2,-3,-4]=>13 [-1,-2,3,4]=>4 [-1,-2,3,-4]=>11 [-1,-2,-3,4]=>9 [-1,-2,-3,-4]=>16 [1,2,4,3]=>1 [1,2,4,-3]=>6 [1,2,-4,3]=>11 [1,2,-4,-3]=>6 [1,-2,4,3]=>4 [1,-2,4,-3]=>9 [1,-2,-4,3]=>14 [1,-2,-4,-3]=>9 [-1,2,4,3]=>2 [-1,2,4,-3]=>7 [-1,2,-4,3]=>12 [-1,2,-4,-3]=>7 [-1,-2,4,3]=>5 [-1,-2,4,-3]=>10 [-1,-2,-4,3]=>15 [-1,-2,-4,-3]=>10 [1,3,2,4]=>1 [1,3,2,-4]=>8 [1,3,-2,4]=>4 [1,3,-2,-4]=>11 [1,-3,2,4]=>7 [1,-3,2,-4]=>14 [1,-3,-2,4]=>4 [1,-3,-2,-4]=>11 [-1,3,2,4]=>2 [-1,3,2,-4]=>9 [-1,3,-2,4]=>5 [-1,3,-2,-4]=>12 [-1,-3,2,4]=>8 [-1,-3,2,-4]=>15 [-1,-3,-2,4]=>5 [-1,-3,-2,-4]=>12 [1,3,4,2]=>2 [1,3,4,-2]=>5 [1,3,-4,2]=>10 [1,3,-4,-2]=>7 [1,-3,4,2]=>8 [1,-3,4,-2]=>5 [1,-3,-4,2]=>10 [1,-3,-4,-2]=>13 [-1,3,4,2]=>3 [-1,3,4,-2]=>6 [-1,3,-4,2]=>11 [-1,3,-4,-2]=>8 [-1,-3,4,2]=>9 [-1,-3,4,-2]=>6 [-1,-3,-4,2]=>11 [-1,-3,-4,-2]=>14 [1,4,2,3]=>3 [1,4,2,-3]=>9 [1,4,-2,3]=>6 [1,4,-2,-3]=>6 [1,-4,2,3]=>12 [1,-4,2,-3]=>6 [1,-4,-2,3]=>9 [1,-4,-2,-3]=>9 [-1,4,2,3]=>4 [-1,4,2,-3]=>10 [-1,4,-2,3]=>7 [-1,4,-2,-3]=>7 [-1,-4,2,3]=>13 [-1,-4,2,-3]=>7 [-1,-4,-2,3]=>10 [-1,-4,-2,-3]=>10 [1,4,3,2]=>2 [1,4,3,-2]=>5 [1,4,-3,2]=>7 [1,4,-3,-2]=>10 [1,-4,3,2]=>8 [1,-4,3,-2]=>5 [1,-4,-3,2]=>13 [1,-4,-3,-2]=>10 [-1,4,3,2]=>3 [-1,4,3,-2]=>6 [-1,4,-3,2]=>8 [-1,4,-3,-2]=>11 [-1,-4,3,2]=>9 [-1,-4,3,-2]=>6 [-1,-4,-3,2]=>14 [-1,-4,-3,-2]=>11 [2,1,3,4]=>1 [2,1,3,-4]=>8 [2,1,-3,4]=>6 [2,1,-3,-4]=>13 [2,-1,3,4]=>2 [2,-1,3,-4]=>9 [2,-1,-3,4]=>7 [2,-1,-3,-4]=>14 [-2,1,3,4]=>3 [-2,1,3,-4]=>10 [-2,1,-3,4]=>8 [-2,1,-3,-4]=>15 [-2,-1,3,4]=>2 [-2,-1,3,-4]=>9 [-2,-1,-3,4]=>7 [-2,-1,-3,-4]=>14 [2,1,4,3]=>2 [2,1,4,-3]=>7 [2,1,-4,3]=>12 [2,1,-4,-3]=>7 [2,-1,4,3]=>3 [2,-1,4,-3]=>8 [2,-1,-4,3]=>13 [2,-1,-4,-3]=>8 [-2,1,4,3]=>4 [-2,1,4,-3]=>9 [-2,1,-4,3]=>14 [-2,1,-4,-3]=>9 [-2,-1,4,3]=>3 [-2,-1,4,-3]=>8 [-2,-1,-4,3]=>13 [-2,-1,-4,-3]=>8 [2,3,1,4]=>2 [2,3,1,-4]=>9 [2,3,-1,4]=>3 [2,3,-1,-4]=>10 [2,-3,1,4]=>6 [2,-3,1,-4]=>13 [2,-3,-1,4]=>5 [2,-3,-1,-4]=>12 [-2,3,1,4]=>4 [-2,3,1,-4]=>11 [-2,3,-1,4]=>3 [-2,3,-1,-4]=>10 [-2,-3,1,4]=>6 [-2,-3,1,-4]=>13 [-2,-3,-1,4]=>7 [-2,-3,-1,-4]=>14 [2,3,4,1]=>3 [2,3,4,-1]=>4 [2,3,-4,1]=>9 [2,3,-4,-1]=>8 [2,-3,4,1]=>7 [2,-3,4,-1]=>6 [2,-3,-4,1]=>11 [2,-3,-4,-1]=>12 [-2,3,4,1]=>5 [-2,3,4,-1]=>4 [-2,3,-4,1]=>9 [-2,3,-4,-1]=>10 [-2,-3,4,1]=>7 [-2,-3,4,-1]=>8 [-2,-3,-4,1]=>13 [-2,-3,-4,-1]=>12 [2,4,1,3]=>4 [2,4,1,-3]=>8 [2,4,-1,3]=>5 [2,4,-1,-3]=>7 [2,-4,1,3]=>11 [2,-4,1,-3]=>7 [2,-4,-1,3]=>10 [2,-4,-1,-3]=>8 [-2,4,1,3]=>6 [-2,4,1,-3]=>8 [-2,4,-1,3]=>5 [-2,4,-1,-3]=>9 [-2,-4,1,3]=>11 [-2,-4,1,-3]=>9 [-2,-4,-1,3]=>12 [-2,-4,-1,-3]=>8 [2,4,3,1]=>3 [2,4,3,-1]=>4 [2,4,-3,1]=>8 [2,4,-3,-1]=>9 [2,-4,3,1]=>7 [2,-4,3,-1]=>6 [2,-4,-3,1]=>12 [2,-4,-3,-1]=>11 [-2,4,3,1]=>5 [-2,4,3,-1]=>4 [-2,4,-3,1]=>10 [-2,4,-3,-1]=>9 [-2,-4,3,1]=>7 [-2,-4,3,-1]=>8 [-2,-4,-3,1]=>12 [-2,-4,-3,-1]=>13 [3,1,2,4]=>3 [3,1,2,-4]=>10 [3,1,-2,4]=>5 [3,1,-2,-4]=>12 [3,-1,2,4]=>4 [3,-1,2,-4]=>11 [3,-1,-2,4]=>4 [3,-1,-2,-4]=>11 [-3,1,2,4]=>6 [-3,1,2,-4]=>13 [-3,1,-2,4]=>4 [-3,1,-2,-4]=>11 [-3,-1,2,4]=>5 [-3,-1,2,-4]=>12 [-3,-1,-2,4]=>5 [-3,-1,-2,-4]=>12 [3,1,4,2]=>4 [3,1,4,-2]=>6 [3,1,-4,2]=>11 [3,1,-4,-2]=>9 [3,-1,4,2]=>5 [3,-1,4,-2]=>5 [3,-1,-4,2]=>10 [3,-1,-4,-2]=>10 [-3,1,4,2]=>7 [-3,1,4,-2]=>5 [-3,1,-4,2]=>10 [-3,1,-4,-2]=>12 [-3,-1,4,2]=>6 [-3,-1,4,-2]=>6 [-3,-1,-4,2]=>11 [-3,-1,-4,-2]=>11 [3,2,1,4]=>2 [3,2,1,-4]=>9 [3,2,-1,4]=>3 [3,2,-1,-4]=>10 [3,-2,1,4]=>5 [3,-2,1,-4]=>12 [3,-2,-1,4]=>6 [3,-2,-1,-4]=>13 [-3,2,1,4]=>4 [-3,2,1,-4]=>11 [-3,2,-1,4]=>3 [-3,2,-1,-4]=>10 [-3,-2,1,4]=>7 [-3,-2,1,-4]=>14 [-3,-2,-1,4]=>6 [-3,-2,-1,-4]=>13 [3,2,4,1]=>3 [3,2,4,-1]=>4 [3,2,-4,1]=>9 [3,2,-4,-1]=>8 [3,-2,4,1]=>6 [3,-2,4,-1]=>7 [3,-2,-4,1]=>12 [3,-2,-4,-1]=>11 [-3,2,4,1]=>5 [-3,2,4,-1]=>4 [-3,2,-4,1]=>9 [-3,2,-4,-1]=>10 [-3,-2,4,1]=>8 [-3,-2,4,-1]=>7 [-3,-2,-4,1]=>12 [-3,-2,-4,-1]=>13 [3,4,1,2]=>4 [3,4,1,-2]=>7 [3,4,-1,2]=>5 [3,4,-1,-2]=>8 [3,-4,1,2]=>10 [3,-4,1,-2]=>7 [3,-4,-1,2]=>11 [3,-4,-1,-2]=>8 [-3,4,1,2]=>6 [-3,4,1,-2]=>9 [-3,4,-1,2]=>5 [-3,4,-1,-2]=>8 [-3,-4,1,2]=>12 [-3,-4,1,-2]=>9 [-3,-4,-1,2]=>11 [-3,-4,-1,-2]=>8 [3,4,2,1]=>5 [3,4,2,-1]=>6 [3,4,-2,1]=>7 [3,4,-2,-1]=>6 [3,-4,2,1]=>9 [3,-4,2,-1]=>8 [3,-4,-2,1]=>9 [3,-4,-2,-1]=>10 [-3,4,2,1]=>8 [-3,4,2,-1]=>7 [-3,4,-2,1]=>6 [-3,4,-2,-1]=>7 [-3,-4,2,1]=>10 [-3,-4,2,-1]=>11 [-3,-4,-2,1]=>10 [-3,-4,-2,-1]=>9 [4,1,2,3]=>6 [4,1,2,-3]=>9 [4,1,-2,3]=>8 [4,1,-2,-3]=>7 [4,-1,2,3]=>7 [4,-1,2,-3]=>8 [4,-1,-2,3]=>7 [4,-1,-2,-3]=>8 [-4,1,2,3]=>10 [-4,1,2,-3]=>7 [-4,1,-2,3]=>8 [-4,1,-2,-3]=>9 [-4,-1,2,3]=>9 [-4,-1,2,-3]=>8 [-4,-1,-2,3]=>9 [-4,-1,-2,-3]=>8 [4,1,3,2]=>4 [4,1,3,-2]=>6 [4,1,-3,2]=>9 [4,1,-3,-2]=>11 [4,-1,3,2]=>5 [4,-1,3,-2]=>5 [4,-1,-3,2]=>10 [4,-1,-3,-2]=>10 [-4,1,3,2]=>7 [-4,1,3,-2]=>5 [-4,1,-3,2]=>12 [-4,1,-3,-2]=>10 [-4,-1,3,2]=>6 [-4,-1,3,-2]=>6 [-4,-1,-3,2]=>11 [-4,-1,-3,-2]=>11 [4,2,1,3]=>5 [4,2,1,-3]=>7 [4,2,-1,3]=>6 [4,2,-1,-3]=>6 [4,-2,1,3]=>8 [4,-2,1,-3]=>10 [4,-2,-1,3]=>9 [4,-2,-1,-3]=>9 [-4,2,1,3]=>8 [-4,2,1,-3]=>6 [-4,2,-1,3]=>7 [-4,2,-1,-3]=>7 [-4,-2,1,3]=>11 [-4,-2,1,-3]=>9 [-4,-2,-1,3]=>10 [-4,-2,-1,-3]=>10 [4,2,3,1]=>3 [4,2,3,-1]=>4 [4,2,-3,1]=>8 [4,2,-3,-1]=>9 [4,-2,3,1]=>6 [4,-2,3,-1]=>7 [4,-2,-3,1]=>11 [4,-2,-3,-1]=>12 [-4,2,3,1]=>5 [-4,2,3,-1]=>4 [-4,2,-3,1]=>10 [-4,2,-3,-1]=>9 [-4,-2,3,1]=>8 [-4,-2,3,-1]=>7 [-4,-2,-3,1]=>13 [-4,-2,-3,-1]=>12 [4,3,1,2]=>5 [4,3,1,-2]=>7 [4,3,-1,2]=>6 [4,3,-1,-2]=>6 [4,-3,1,2]=>9 [4,-3,1,-2]=>9 [4,-3,-1,2]=>8 [4,-3,-1,-2]=>10 [-4,3,1,2]=>8 [-4,3,1,-2]=>6 [-4,3,-1,2]=>7 [-4,3,-1,-2]=>7 [-4,-3,1,2]=>10 [-4,-3,1,-2]=>10 [-4,-3,-1,2]=>11 [-4,-3,-1,-2]=>9 [4,3,2,1]=>4 [4,3,2,-1]=>5 [4,3,-2,1]=>7 [4,3,-2,-1]=>8 [4,-3,2,1]=>10 [4,-3,2,-1]=>11 [4,-3,-2,1]=>7 [4,-3,-2,-1]=>8 [-4,3,2,1]=>6 [-4,3,2,-1]=>5 [-4,3,-2,1]=>9 [-4,3,-2,-1]=>8 [-4,-3,2,1]=>12 [-4,-3,2,-1]=>11 [-4,-3,-2,1]=>9 [-4,-3,-2,-1]=>8
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Description
The sorting index of a signed permutation.
A signed permutation $\sigma = [\sigma(1),\ldots,\sigma(n)]$ can be sorted $[1,\ldots,n]$ by signed transpositions in the following way:
First move $\pm n$ to its position and swap the sign if needed, then $\pm (n-1), \pm (n-2)$ and so on.
For example for $[2,-4,5,-1,-3]$ we have the swaps
$$ [2,-4,5,-1,-3] \rightarrow [2,-4,-3,-1,5] \rightarrow [2,1,-3,4,5] \rightarrow [2,1,3,4,5] \rightarrow [1,2,3,4,5] $$
given by the signed transpositions $(3,5), (-2,4), (-3,3), (1,2)$.
If $(i_1,j_1),\ldots,(i_n,j_n)$ is the decomposition of $\sigma$ obtained this way (including trivial transpositions) then the sorting index of $\sigma$ is defined as
$$ \operatorname{sor}_B(\sigma) = \sum_{k=1}^{n-1} j_k - i_k - \chi(i_k < 0), $$
where $\chi(i_k < 0)$ is 1 if $i_k$ is negative and 0 otherwise.
For $\sigma = [2,-4,5,-1,-3]$ we have
$$ \operatorname{sor}_B(\sigma) = (5-3) + (4-(-2)-1) + (3-(-3)-1) + (2-1) = 13. $$
References
[1] Petersen, T. K. The sorting index arXiv:1007.1207
Code
def statistic(pi):
    T = []
    n = pi.parent().rank()
    w = list(pi)
    iw = [abs(i) for i in w]
    
    for i in range(n):
        ind = iw.index(n - i)
        
        if ind + 1 < iw[ind]:
            T.append([sgn(w[ind]) * (ind+1), n-i])
            w[ind] = sgn(w[ind]) * w[n-i-1]
            w[n-i-1] = n-i
        
        if ind + 1 == iw[ind] and w[ind] < ind + 1:
            T.append([-(ind+1),ind+1])
            w[ind] = -w[ind]
        
        iw = [abs(x) for x in w]

    sort = 0
    for t in T:
        if t[0] > 0:
            sort += (t[1] - t[0])
        else:
            sort += (t[1] - t[0] - 1)
    
    return sort
Created
Jul 21, 2022 at 15:03 by Dennis Jahn
Updated
Jul 21, 2022 at 15:03 by Dennis Jahn