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Identifier
Values
[1] => [1,0] => [1,0] => [1,0] => 0
[1,1] => [1,0,1,0] => [1,1,0,0] => [1,0,1,0] => 1
[2] => [1,1,0,0] => [1,0,1,0] => [1,1,0,0] => 0
[1,1,1] => [1,0,1,0,1,0] => [1,1,1,0,0,0] => [1,1,0,1,0,0] => 2
[1,2] => [1,0,1,1,0,0] => [1,0,1,1,0,0] => [1,1,0,0,1,0] => 1
[3] => [1,1,1,0,0,0] => [1,0,1,0,1,0] => [1,1,1,0,0,0] => 0
[1,1,1,1] => [1,0,1,0,1,0,1,0] => [1,1,1,1,0,0,0,0] => [1,1,1,0,1,0,0,0] => 3
[1,1,2] => [1,0,1,0,1,1,0,0] => [1,0,1,1,1,0,0,0] => [1,1,1,0,0,1,0,0] => 2
[1,3] => [1,0,1,1,1,0,0,0] => [1,0,1,0,1,1,0,0] => [1,1,1,0,0,0,1,0] => 1
[4] => [1,1,1,1,0,0,0,0] => [1,0,1,0,1,0,1,0] => [1,1,1,1,0,0,0,0] => 0
[1,1,1,1,1] => [1,0,1,0,1,0,1,0,1,0] => [1,1,1,1,1,0,0,0,0,0] => [1,1,1,1,0,1,0,0,0,0] => 4
[1,1,1,2] => [1,0,1,0,1,0,1,1,0,0] => [1,0,1,1,1,1,0,0,0,0] => [1,1,1,1,0,0,1,0,0,0] => 3
[1,1,3] => [1,0,1,0,1,1,1,0,0,0] => [1,0,1,0,1,1,1,0,0,0] => [1,1,1,1,0,0,0,1,0,0] => 2
[1,4] => [1,0,1,1,1,1,0,0,0,0] => [1,0,1,0,1,0,1,1,0,0] => [1,1,1,1,0,0,0,0,1,0] => 1
[5] => [1,1,1,1,1,0,0,0,0,0] => [1,0,1,0,1,0,1,0,1,0] => [1,1,1,1,1,0,0,0,0,0] => 0
[1,1,1,1,1,1] => [1,0,1,0,1,0,1,0,1,0,1,0] => [1,1,1,1,1,1,0,0,0,0,0,0] => [1,1,1,1,1,0,1,0,0,0,0,0] => 5
[1,1,1,1,2] => [1,0,1,0,1,0,1,0,1,1,0,0] => [1,0,1,1,1,1,1,0,0,0,0,0] => [1,1,1,1,1,0,0,1,0,0,0,0] => 4
[1,1,1,3] => [1,0,1,0,1,0,1,1,1,0,0,0] => [1,0,1,0,1,1,1,1,0,0,0,0] => [1,1,1,1,1,0,0,0,1,0,0,0] => 3
[1,1,4] => [1,0,1,0,1,1,1,1,0,0,0,0] => [1,0,1,0,1,0,1,1,1,0,0,0] => [1,1,1,1,1,0,0,0,0,1,0,0] => 2
[1,5] => [1,0,1,1,1,1,1,0,0,0,0,0] => [1,0,1,0,1,0,1,0,1,1,0,0] => [1,1,1,1,1,0,0,0,0,0,1,0] => 1
[6] => [1,1,1,1,1,1,0,0,0,0,0,0] => [1,0,1,0,1,0,1,0,1,0,1,0] => [1,1,1,1,1,1,0,0,0,0,0,0] => 0
[1,1,1,1,1,1,1] => [1,0,1,0,1,0,1,0,1,0,1,0,1,0] => [1,1,1,1,1,1,1,0,0,0,0,0,0,0] => [1,1,1,1,1,1,0,1,0,0,0,0,0,0] => 6
[1,1,1,1,1,2] => [1,0,1,0,1,0,1,0,1,0,1,1,0,0] => [1,0,1,1,1,1,1,1,0,0,0,0,0,0] => [1,1,1,1,1,1,0,0,1,0,0,0,0,0] => 5
[1,1,1,1,3] => [1,0,1,0,1,0,1,0,1,1,1,0,0,0] => [1,0,1,0,1,1,1,1,1,0,0,0,0,0] => [1,1,1,1,1,1,0,0,0,1,0,0,0,0] => 4
[1,1,1,4] => [1,0,1,0,1,0,1,1,1,1,0,0,0,0] => [1,0,1,0,1,0,1,1,1,1,0,0,0,0] => [1,1,1,1,1,1,0,0,0,0,1,0,0,0] => 3
[1,1,5] => [1,0,1,0,1,1,1,1,1,0,0,0,0,0] => [1,0,1,0,1,0,1,0,1,1,1,0,0,0] => [1,1,1,1,1,1,0,0,0,0,0,1,0,0] => 2
[1,6] => [1,0,1,1,1,1,1,1,0,0,0,0,0,0] => [1,0,1,0,1,0,1,0,1,0,1,1,0,0] => [1,1,1,1,1,1,0,0,0,0,0,0,1,0] => 1
[7] => [1,1,1,1,1,1,1,0,0,0,0,0,0,0] => [1,0,1,0,1,0,1,0,1,0,1,0,1,0] => [1,1,1,1,1,1,1,0,0,0,0,0,0,0] => 0
search for individual values
searching the database for the individual values of this statistic
/ search for generating function
searching the database for statistics with the same generating function
Description
The number of indecomposable modules with projective dimension 2 for Nakayama algebras with global dimension at most 2.
Map
zeta map
Description
The zeta map on Dyck paths.
The zeta map ζ is a bijection on Dyck paths of semilength n.
It was defined in [1, Theorem 1], see also [2, Theorem 3.15] and sends the bistatistic (area, dinv) to the bistatistic (bounce, area). It is defined by sending a Dyck path D with corresponding area sequence a=(a1,,an) to a Dyck path as follows:
  • First, build an intermediate Dyck path consisting of d1 north steps, followed by d1 east steps, followed by d2 north steps and d2 east steps, and so on, where di is the number of i1's within the sequence a.
    For example, given a=(0,1,2,2,2,3,1,2), we build the path
    NE NNEE NNNNEEEE NE.
  • Next, the rectangles between two consecutive peaks are filled. Observe that such the rectangle between the kth and the (k+1)st peak must be filled by dk east steps and dk+1 north steps. In the above example, the rectangle between the second and the third peak must be filled by 2 east and 4 north steps, the 2 being the number of 1's in a, and 4 being the number of 2's. To fill such a rectangle, scan through the sequence a from left to right, and add east or north steps whenever you see a k1 or k, respectively. So to fill the 2×4 rectangle, we look for 1's and 2's in the sequence and see 122212, so this rectangle gets filled with ENNNEN.
    The complete path we obtain in thus
    NENNENNNENEEENEE.
Map
peaks-to-valleys
Description
Return the path that has a valley wherever the original path has a peak of height at least one.
More precisely, the height of a valley in the image is the height of the corresponding peak minus 2.
This is also (the inverse of) rowmotion on Dyck paths regarded as order ideals in the triangular poset.
Map
bounce path
Description
The bounce path determined by an integer composition.