Identifier
Values
[1,0,1,0] => [1,2] => ([(0,1)],2) => 1
[1,1,0,0] => [2,1] => ([],2) => 0
[1,0,1,0,1,0] => [1,2,3] => ([(0,2),(2,1)],3) => 2
[1,0,1,1,0,0] => [1,3,2] => ([(0,1),(0,2)],3) => 2
[1,1,0,0,1,0] => [2,1,3] => ([(0,2),(1,2)],3) => 2
[1,1,0,1,0,0] => [2,3,1] => ([(1,2)],3) => 1
[1,1,1,0,0,0] => [3,2,1] => ([],3) => 0
[1,0,1,0,1,0,1,0] => [1,2,3,4] => ([(0,3),(2,1),(3,2)],4) => 3
[1,0,1,0,1,1,0,0] => [1,2,4,3] => ([(0,3),(3,1),(3,2)],4) => 3
[1,0,1,1,0,0,1,0] => [1,3,2,4] => ([(0,1),(0,2),(1,3),(2,3)],4) => 4
[1,0,1,1,0,1,0,0] => [1,3,4,2] => ([(0,2),(0,3),(3,1)],4) => 3
[1,0,1,1,1,0,0,0] => [1,4,3,2] => ([(0,1),(0,2),(0,3)],4) => 3
[1,1,0,0,1,0,1,0] => [2,1,3,4] => ([(0,3),(1,3),(3,2)],4) => 3
[1,1,0,0,1,1,0,0] => [2,1,4,3] => ([(0,2),(0,3),(1,2),(1,3)],4) => 4
[1,1,0,1,0,0,1,0] => [2,3,1,4] => ([(0,3),(1,2),(2,3)],4) => 3
[1,1,0,1,0,1,0,0] => [2,3,4,1] => ([(1,2),(2,3)],4) => 2
[1,1,0,1,1,0,0,0] => [2,4,3,1] => ([(1,2),(1,3)],4) => 2
[1,1,1,0,0,0,1,0] => [3,2,1,4] => ([(0,3),(1,3),(2,3)],4) => 3
[1,1,1,0,0,1,0,0] => [3,2,4,1] => ([(1,3),(2,3)],4) => 2
[1,1,1,0,1,0,0,0] => [4,2,3,1] => ([(2,3)],4) => 1
[1,1,1,1,0,0,0,0] => [4,3,2,1] => ([],4) => 0
[1,0,1,0,1,0,1,0,1,0] => [1,2,3,4,5] => ([(0,4),(2,3),(3,1),(4,2)],5) => 4
[1,0,1,0,1,0,1,1,0,0] => [1,2,3,5,4] => ([(0,3),(3,4),(4,1),(4,2)],5) => 4
[1,0,1,0,1,1,0,0,1,0] => [1,2,4,3,5] => ([(0,3),(1,4),(2,4),(3,1),(3,2)],5) => 5
[1,0,1,0,1,1,0,1,0,0] => [1,2,4,5,3] => ([(0,4),(3,2),(4,1),(4,3)],5) => 4
[1,0,1,0,1,1,1,0,0,0] => [1,2,5,4,3] => ([(0,4),(4,1),(4,2),(4,3)],5) => 4
[1,0,1,1,0,0,1,0,1,0] => [1,3,2,4,5] => ([(0,2),(0,3),(2,4),(3,4),(4,1)],5) => 5
[1,0,1,1,0,0,1,1,0,0] => [1,3,2,5,4] => ([(0,1),(0,2),(1,3),(1,4),(2,3),(2,4)],5) => 6
[1,0,1,1,0,1,0,0,1,0] => [1,3,4,2,5] => ([(0,2),(0,3),(1,4),(2,4),(3,1)],5) => 5
[1,0,1,1,0,1,0,1,0,0] => [1,3,4,5,2] => ([(0,2),(0,4),(3,1),(4,3)],5) => 4
[1,0,1,1,0,1,1,0,0,0] => [1,3,5,4,2] => ([(0,3),(0,4),(4,1),(4,2)],5) => 4
[1,0,1,1,1,0,0,0,1,0] => [1,4,3,2,5] => ([(0,1),(0,2),(0,3),(1,4),(2,4),(3,4)],5) => 6
[1,0,1,1,1,0,0,1,0,0] => [1,4,3,5,2] => ([(0,1),(0,2),(0,3),(2,4),(3,4)],5) => 5
[1,0,1,1,1,0,1,0,0,0] => [1,5,3,4,2] => ([(0,2),(0,3),(0,4),(4,1)],5) => 4
[1,0,1,1,1,1,0,0,0,0] => [1,5,4,3,2] => ([(0,1),(0,2),(0,3),(0,4)],5) => 4
[1,1,0,0,1,0,1,0,1,0] => [2,1,3,4,5] => ([(0,4),(1,4),(2,3),(4,2)],5) => 4
[1,1,0,0,1,0,1,1,0,0] => [2,1,3,5,4] => ([(0,4),(1,4),(4,2),(4,3)],5) => 4
[1,1,0,0,1,1,0,0,1,0] => [2,1,4,3,5] => ([(0,3),(0,4),(1,3),(1,4),(3,2),(4,2)],5) => 6
[1,1,0,0,1,1,0,1,0,0] => [2,1,4,5,3] => ([(0,3),(0,4),(1,3),(1,4),(4,2)],5) => 5
[1,1,0,0,1,1,1,0,0,0] => [2,1,5,4,3] => ([(0,2),(0,3),(0,4),(1,2),(1,3),(1,4)],5) => 6
[1,1,0,1,0,0,1,0,1,0] => [2,3,1,4,5] => ([(0,4),(1,2),(2,4),(4,3)],5) => 4
[1,1,0,1,0,0,1,1,0,0] => [2,3,1,5,4] => ([(0,3),(0,4),(1,2),(2,3),(2,4)],5) => 5
[1,1,0,1,0,1,0,0,1,0] => [2,3,4,1,5] => ([(0,4),(1,2),(2,3),(3,4)],5) => 4
[1,1,0,1,0,1,0,1,0,0] => [2,3,4,5,1] => ([(1,4),(3,2),(4,3)],5) => 3
[1,1,0,1,0,1,1,0,0,0] => [2,3,5,4,1] => ([(1,4),(4,2),(4,3)],5) => 3
[1,1,0,1,1,0,0,0,1,0] => [2,4,3,1,5] => ([(0,4),(1,2),(1,3),(2,4),(3,4)],5) => 5
[1,1,0,1,1,0,0,1,0,0] => [2,4,3,5,1] => ([(1,2),(1,3),(2,4),(3,4)],5) => 4
[1,1,0,1,1,0,1,0,0,0] => [2,5,3,4,1] => ([(1,3),(1,4),(4,2)],5) => 3
[1,1,0,1,1,1,0,0,0,0] => [2,5,4,3,1] => ([(1,2),(1,3),(1,4)],5) => 3
[1,1,1,0,0,0,1,0,1,0] => [3,2,1,4,5] => ([(0,4),(1,4),(2,4),(4,3)],5) => 4
[1,1,1,0,0,0,1,1,0,0] => [3,2,1,5,4] => ([(0,3),(0,4),(1,3),(1,4),(2,3),(2,4)],5) => 6
[1,1,1,0,0,1,0,0,1,0] => [3,2,4,1,5] => ([(0,4),(1,3),(2,3),(3,4)],5) => 4
[1,1,1,0,0,1,0,1,0,0] => [3,2,4,5,1] => ([(1,4),(2,4),(4,3)],5) => 3
[1,1,1,0,0,1,1,0,0,0] => [3,2,5,4,1] => ([(1,3),(1,4),(2,3),(2,4)],5) => 4
[1,1,1,0,1,0,0,0,1,0] => [4,2,3,1,5] => ([(0,4),(1,4),(2,3),(3,4)],5) => 4
[1,1,1,0,1,0,0,1,0,0] => [4,2,3,5,1] => ([(1,4),(2,3),(3,4)],5) => 3
[1,1,1,0,1,0,1,0,0,0] => [5,2,3,4,1] => ([(2,3),(3,4)],5) => 2
[1,1,1,0,1,1,0,0,0,0] => [5,2,4,3,1] => ([(2,3),(2,4)],5) => 2
[1,1,1,1,0,0,0,0,1,0] => [4,3,2,1,5] => ([(0,4),(1,4),(2,4),(3,4)],5) => 4
[1,1,1,1,0,0,0,1,0,0] => [4,3,2,5,1] => ([(1,4),(2,4),(3,4)],5) => 3
[1,1,1,1,0,0,1,0,0,0] => [5,3,2,4,1] => ([(2,4),(3,4)],5) => 2
[1,1,1,1,0,1,0,0,0,0] => [5,3,4,2,1] => ([(3,4)],5) => 1
[1,1,1,1,1,0,0,0,0,0] => [5,4,3,2,1] => ([],5) => 0
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Description
The number of cover relations in a poset.
Equivalently, this is also the number of edges in the Hasse diagram [1].
Map
permutation poset
Description
Sends a permutation to its permutation poset.
For a permutation $\pi$ of length $n$, this poset has vertices
$$\{ (i,\pi(i))\ :\ 1 \leq i \leq n \}$$
and the cover relation is given by $(w, x) \leq (y, z)$ if $w \leq y$ and $x \leq z$.
For example, the permutation $[3,1,5,4,2]$ is mapped to the poset with cover relations
$$\{ (2, 1) \prec (5, 2),\ (2, 1) \prec (4, 4),\ (2, 1) \prec (3, 5),\ (1, 3) \prec (4, 4),\ (1, 3) \prec (3, 5) \}.$$
Map
to non-crossing permutation
Description
Sends a Dyck path $D$ with valley at positions $\{(i_1,j_1),\ldots,(i_k,j_k)\}$ to the unique non-crossing permutation $\pi$ having descents $\{i_1,\ldots,i_k\}$ and whose inverse has descents $\{j_1,\ldots,j_k\}$.
It sends the area St000012The area of a Dyck path. to the number of inversions St000018The number of inversions of a permutation. and the major index St000027The major index of a Dyck path. to $n(n-1)$ minus the sum of the major index St000004The major index of a permutation. and the inverse major index St000305The inverse major index of a permutation..